Merge pull request #907 from heroku/refactor-sqlite

Bug fix: fragile sqlite install

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @heroku/languages

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,8 @@
+<!-- Hi and welcome to the Heroku Python buildpack repository!
+
+If you meant to open a PR against a fork instead of upstream, please adjust the base branch:
+https://help.github.com/articles/changing-the-base-branch-of-a-pull-request/
+
+Otherwise thank you in advance for your Pull Request - just remember to
+include as much information as possible to help the reviewers :-)
+-->

.github/workflows/check_changelog.yml

@@ -0,0 +1,12 @@
+name: Check Changelog
+
+on: [pull_request]
+
+jobs:
+ build:
+   runs-on: ubuntu-latest
+   steps:
+   - uses: actions/checkout@v1
+   - name: Check that CHANGELOG is touched
+     run: |
+       cat $GITHUB_EVENT_PATH | jq .pull_request.title |  grep -i '\[\(\(changelog skip\)\|\(ci skip\)\)\]' ||  git diff remotes/origin/${{ github.base_ref }} --name-only | grep CHANGELOG.md

.gitignore

@@ -1,3 +1,12 @@
 *.pyc
 site
 .DS_Store
+
+/.envrc
+repos/*
+
+#Venv
+buildpack/*
+
+builds/dockerenv.staging*
+builds/dockerenv.production

.pre-commit-config.yaml

@@ -0,0 +1,7 @@
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.3.0
+    hooks:
+    -   id: check-yaml
+    -   id: end-of-file-fixer
+    -   id: trailing-whitespace

.travis.yml

@@ -1,9 +1,39 @@
-language: bash
+language: ruby
+dist: trusty
 sudo: required
-services:
-  - docker
-# install: docker pull heroku/cedar:14
-script: ./tests.sh
+
+rvm:
+- 2.4.4
+before_script:
+  - gem install bundler -v 1.16.2
+  - bundle exec hatchet ci:setup
+
+script:
+  - docker build --pull --tag travis-build-cedar-14 --file $(pwd)/builds/cedar-14.Dockerfile .
+  - docker run --rm -e "STACK=cedar-14" -e "USE_STAGING_BINARIES=$USE_STAGING_BINARIES" travis-build-cedar-14 bash $TESTFOLDER
+  - docker build --pull --tag travis-build-heroku-16 --file $(pwd)/builds/heroku-16.Dockerfile .
+  - docker run --rm -e "STACK=heroku-16" -e "USE_STAGING_BINARIES=$USE_STAGING_BINARIES" travis-build-heroku-16 bash $TESTFOLDER
+  - docker build --pull --tag travis-build-heroku-18 --file $(pwd)/builds/heroku-18.Dockerfile .
+  - docker run --rm -e "STACK=heroku-18" -e "USE_STAGING_BINARIES=$USE_STAGING_BINARIES" travis-build-heroku-18 bash $TESTFOLDER
+
+jobs:
+  include:
+  - stage: Bash linting (shellcheck)
+    sudo: false
+    script: make check
+  - stage: Hatchet Integration
+    if: branch = master
+    name: Run Hatchet
+    script: "bundle exec rspec"
 env:
-  - STACK=heroku-16
-  - STACK=cedar-14
+  matrix:
+    - TESTFOLDER=test/run-deps
+    - TESTFOLDER=test/run-versions
+    - TESTFOLDER=test/run-features
+  global:
+    - HATCHET_RETRIES=3
+    - IS_RUNNING_ON_CI=true
+    - HATCHET_APP_LIMIT=5
+    - HATCHET_DEPLOY_STRATEGY=git
+    - secure: yjtlPE5FbVxTKnjUy/tZUBgSEf4qADD3QOxtgziuid73S0U/1IEXlMGFULsQzIjtlHKmHeywZqpVVEpthIH4RuT7uoX1Pb7SSM/g0T8fT3VoEFbFK1uYl0oZQbUS4Klxv9tPiumj8if3m6ULEGIz1X0wZcMOC0tMLwVCnwmap0E=
+    - secure: ZeFTHWwnpIKE9nAqs88ocmiQh7bKce84lilGm5J23nf3N6V4wNyLwqlkvsM008WGBCaOg9AUx7ZunasT0ANsR5gLP3eV2UUg7ILdRgV2Gy13eNRFheC4PHdN92RqQ3aKoqlIv2K999xlhVjod0NzhkQQXB6PddfQINbuU7ks6As=

CHANGELOG.md

@@ -1,18 +1,247 @@
 # Python Buildpack Changelog
 
+# Master
+
+- Bug fix: fragile sqlite3 install
+
+--------------------------------------------------------------------------------
+
+# 161 (2019-12-2)
+
+- Bug fix: Sqlite3 version bump
+
+# 160 (2019-10-23)
+
+- Bugfix: Pipenv no longer installs twice in CI
+
+# 159 (2019-10-22)
+
+- Python 2.7.17 now available on Heroku 18 and 16.
+
+# 158 (2019-10-21)
+
+- Python 3.7.5 and 3.8.0 now available on Heroku 18 and 16.
+- Add support for Python 3.8 branch
+- Sqlite3 Update:
+  - Test Improvements
+- Add support for staging binary testing
+
+# 157 (2019-09-18)
+
+- Typo fixes
+
+# 156 (2019-09-12)
+
+- Python 3.6.9 and 3.7.4 now available.
+
+- Move get-pip utility to S3
+- Build utility and documentation updates
+- Bump Hatchet tests to point at new default python version.
+
+# 155 (2019-08-22)
+
+add docs and make target for heroku-18 bob builds
+
+# 154 (2019-07-17)
+
+Fix python 3.5.7 formula actually building 3.7.2
+
+# 153 (2019-06-21)
+
+Hotfix for broken heroku-16 deploys
+
+# 152 (2019-04-04)
+
+Python 3.7.3 now available.
+
+# 151 (2019-03-21)
+
+Python 3.5.7 and 3.4.10 now available on all Heroku stacks.
+
+# 150 (2019-03-13)
+
+Python 2.7.16 now available on all Heroku stacks.
+
+# 149 (2019-03-04)
+
+Hotfix for broken Cedar 14 deploys
+
+# 148 (2019-02-21)
+
+No user facing changes, improving internal metrics
+
+# 147 (2019-02-07)
+
+Python 3.7.2 and 3.6.8 now available on all Heroku stacks.
+
+# 146 (2018-11-11)
+
+Python 3.7.1, 3.6.7, 3.5.6 and 3.4.9 now available on all Heroku stacks.
+
+# 145 (2018-11-08)
+
+Testing and tooling expanded to better support new runtimes
+
+# 144 (2018-10-10)
+
+Switch to cautious upgrade for Pipenv install to ensure the pinned pip version
+is used with Pipenv
+
+# 143 (2018-10-09)
+
+Add support for detecting SLUGIFY_USES_TEXT_UNIDECODE, which is required to
+install Apache Airflow version 1.10 or higher.
+
+# 142 (2018-10-08)
+
+Improvements to Python install messaging
+
+# 139, 140, 141
+
+No user-facing changes, documenting for version clarity
+
+# 138 (2018-08-01)
+
+Use stack image SQLite3 instead of vendoring
+
+# 137 (2018-07-17)
+
+Prevent 3.7.0 from appearing as unsupported in buildpack messaging.
+
+# 136 (2018-06-28)
+
+Upgrade to 3.6.6 and support 3.7.0 on all runtimes.
+
+# 135 (2018-05-29)
+
+Upgrade Pipenv to v2018.5.18.
+
+# 134 (2018-05-02)
+
+Default to 3.6.5, bugfixes.
+
+# 133
+
+Fixes for Pip 10 release.
+
+# 132
+
+Improve pip installation, with the release of v9.0.2.
+
+# 131
+
+Fix bug with pip.
+
+# 130
+
+Better upgrade strategy for pip.
+
+# 129
+
+Don't upgrade pip (from v128).
+
+# 128
+
+Upgrade pip, pin to Pipenv v11.8.2.
+
+# 127
+
+Pin to Pipenv v11.7.1.
+
+# 126
+
+Bugfixes.
+
+# 125
+
+Bugfixes.
+
+# 124
+
+Update buildpack to automatically install `[dev-packages]` during Heroku CI Pipenv builds.
+
+- Skip installs if Pipfile.lock hasn't changed, and uninstall stale dependencies with Pipenv.
+- Set `PYTHONPATH` during collectstatic runs.
+- No longer warn if there is no `Procfile`.
+- Update Pipenv's "3.6" runtime specifier to point to "3.6.4".
+
+# 123
+
+Update gunicorn `init.d` script to allow overrides.
+
+# 122
+
+Update default Python to v3.6.4.
+
+# 121
+
+Update default Python to v3.6.3.
+
+# 120
+
+Use `$ pipenv --deploy`.
+
+# 119
+
+Improvements to Pipenv support, warning on unsupported Python versions.
+
+- We now warn when a user is not using latest 2.x or 3.x Python.
+- Heroku now supports `[requires]` `python_full_version` in addition to `python_version`.
+
+# 118
+
+Improvements to Pipenv support.
+
+# 117
+
+Bug fix.
+
+# 116
+
+Vendoring improvements.
+
+- Geos libraries should work on Heroku-16 now.
+- The libffi/libmemcached vendoring step is now skipped on Heroku-16 (since they are installed in the base image).
+
+# 115
+
+Revert a pull request.
+
+- No longer using `sub_env` for `pip install` step.
+
+# 114
+
+- Bugfixes.
+
+Blacklisting `PYTHONHOME` and `PYTHONPATH` for older apps. Upgrades to nltk support.
+
+# 113
+
+Updates to Pipenv support.
+
+# 112
+
+Bugfix.
+
+- Fixed grep output bug.
+
+# 111
+
+Linting, bugfixes.
+
 # 110
 
+Update default Python to 3.6.2.
+
+# 109
+
 Update Default Python to 3.6.1, bugfixes.
 
 - Fixed automatic pip uninstall of dependencies removed from requirements.txt.
 
-# 109
-
-Fix output for collectstatic step.
-
 # 108
 
-Updated setuptools.
+Fix output for collectstatic step.
 
 # 107
 

Gemfile

@@ -0,0 +1,6 @@
+source "https://rubygems.org"
+
+gem "rspec"
+gem "heroku_hatchet"
+gem "rspec-retry"
+gem "rake"

Gemfile.lock

@@ -0,0 +1,71 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    activesupport (5.2.1)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
+      minitest (~> 5.1)
+      tzinfo (~> 1.1)
+    concurrent-ruby (1.1.3)
+    diff-lcs (1.3)
+    erubis (2.7.0)
+    excon (0.62.0)
+    heroics (0.0.25)
+      erubis (~> 2.0)
+      excon
+      moneta
+      multi_json (>= 1.9.2)
+    heroku_hatchet (4.0.6)
+      excon (~> 0)
+      minitest-retry (~> 0.1.9)
+      platform-api (~> 2)
+      repl_runner (~> 0.0.3)
+      rrrretry (~> 1)
+      thor (~> 0)
+      threaded (~> 0)
+    i18n (1.1.1)
+      concurrent-ruby (~> 1.0)
+    minitest (5.11.3)
+    minitest-retry (0.1.9)
+      minitest (>= 5.0)
+    moneta (1.0.0)
+    multi_json (1.13.1)
+    platform-api (2.2.0)
+      heroics (~> 0.0.25)
+      moneta (~> 1.0.0)
+    rake (12.3.1)
+    repl_runner (0.0.3)
+      activesupport
+    rrrretry (1.0.0)
+    rspec (3.8.0)
+      rspec-core (~> 3.8.0)
+      rspec-expectations (~> 3.8.0)
+      rspec-mocks (~> 3.8.0)
+    rspec-core (3.8.0)
+      rspec-support (~> 3.8.0)
+    rspec-expectations (3.8.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.8.0)
+    rspec-mocks (3.8.0)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.8.0)
+    rspec-retry (0.6.1)
+      rspec-core (> 3.3)
+    rspec-support (3.8.0)
+    thor (0.20.3)
+    thread_safe (0.3.6)
+    threaded (0.0.4)
+    tzinfo (1.2.5)
+      thread_safe (~> 0.1)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  heroku_hatchet
+  rake
+  rspec
+  rspec-retry
+
+BUNDLED WITH
+   1.16.3

Makefile

@@ -1,22 +1,32 @@
 # These targets are not files
 .PHONY: tests
 
-test: test-cedar-14
+test: test-heroku-18 test-heroku-16 test-cedar-14
+
+check:
+	@shellcheck -x bin/compile bin/detect bin/release bin/test-compile bin/utils bin/warnings bin/default_pythons
+	@shellcheck -x bin/steps/collectstatic bin/steps/eggpath-fix  bin/steps/eggpath-fix2 bin/steps/gdal bin/steps/geo-libs bin/steps/mercurial bin/steps/nltk bin/steps/pip-install bin/steps/pip-uninstall bin/steps/pipenv bin/steps/pipenv-python-version bin/steps/pylibmc bin/steps/python
+	@shellcheck -x bin/steps/hooks/*
 
 test-cedar-14:
 	@echo "Running tests in docker (cedar-14)..."
-	@docker run -v $(shell pwd):/buildpack:ro --rm -it -e "STACK=cedar-14" heroku/cedar:14 bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
+	@docker run -v $(shell pwd):/buildpack:ro --rm -it -e "STACK=cedar-14" heroku/cedar:14 bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run-deps; test/run-features; test/run-versions;'
 	@echo ""
 
 test-heroku-16:
 	@echo "Running tests in docker (heroku-16)..."
-	@docker run -v $(shell pwd):/buildpack:ro --rm -it -e "STACK=heroku-16" heroku/heroku:16-build bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
+	@docker run -v $(shell pwd):/buildpack:ro --rm -it -e "STACK=heroku-16" heroku/heroku:16-build bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run-deps; test/run-features; test/run-versions;'
+	@echo ""
+
+test-heroku-18:
+	@echo "Running tests in docker (heroku-18)..."
+	@docker run -v $(shell pwd):/buildpack:ro --rm -it -e "STACK=heroku-18" heroku/heroku:18-build bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run-deps; test/run-features; test/run-versions;'
 	@echo ""
 
 buildenv-heroku-16:
 	@echo "Creating build environment (heroku-16)..."
 	@echo
-	@docker build --pull -t python-buildenv-heroku-16 .
+	@docker build --pull -f $(shell pwd)/builds/heroku-16.Dockerfile -t python-buildenv-heroku-16 .
 	@echo
 	@echo "Usage..."
 	@echo
@@ -26,6 +36,19 @@ buildenv-heroku-16:
 	@echo
 	@docker run -it --rm python-buildenv-heroku-16
 
+buildenv-heroku-18:
+	@echo "Creating build environment (heroku-18)..."
+	@echo
+	@docker build --pull -f $(shell pwd)/builds/heroku-18.Dockerfile -t python-buildenv-heroku-18 .
+	@echo
+	@echo "Usage..."
+	@echo
+	@echo "  $$ export AWS_ACCESS_KEY_ID=foo AWS_SECRET_ACCESS_KEY=bar  # Optional unless deploying"
+	@echo "  $$ bob build runtimes/python-2.7.13"
+	@echo "  $$ bob deploy runtimes/python-2.7.13"
+	@echo
+	@docker run -it --rm python-buildenv-heroku-18
+
 tools:
 	git clone https://github.com/kennethreitz/pip-pop.git
 	mv pip-pop/bin/* vendor/pip-pop/

Pipfile

@@ -0,0 +1,9 @@
+[[source]]
+url = "https://pypi.python.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[dev-packages]
+
+[packages]
+"bob-builder" = "==0.0.13"

Pipfile.lock

@@ -0,0 +1,52 @@
+{
+    "_meta": {
+        "hash": {
+            "sha256": "36d17c46a8b1b844b3cae475f6f42d6c0a9e59b2a9685cbcdc0985656a7a129f"
+        },
+        "host-environment-markers": {
+            "implementation_name": "cpython",
+            "implementation_version": "3.6.3",
+            "os_name": "posix",
+            "platform_machine": "x86_64",
+            "platform_python_implementation": "CPython",
+            "platform_release": "16.7.0",
+            "platform_system": "Darwin",
+            "platform_version": "Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64",
+            "python_full_version": "3.6.3",
+            "python_version": "3.6",
+            "sys_platform": "darwin"
+        },
+        "pipfile-spec": 6,
+        "requires": {},
+        "sources": [
+            {
+                "name": "pypi",
+                "url": "https://pypi.python.org/simple",
+                "verify_ssl": true
+            }
+        ]
+    },
+    "default": {
+        "bob-builder": {
+            "hashes": [
+                "sha256:b4de49a8e436fcaf82236ea43f78413b4a4c92100726e382ab57b6bdfb38fe64",
+                "sha256:288e3e765c4890fe9a63ae52ac6b4a963c13fe508482c70ff701a5ae21b9a673"
+            ],
+            "version": "==0.0.13"
+        },
+        "boto": {
+            "hashes": [
+                "sha256:13be844158d1bd80a94c972c806ec8381b9ea72035aa06123c5db6bc6a6f3ead",
+                "sha256:deb8925b734b109679e3de65856018996338758f4b916ff4fe7bb62b6d7000d1"
+            ],
+            "version": "==2.48.0"
+        },
+        "docopt": {
+            "hashes": [
+                "sha256:49b3a825280bd66b3aa83585ef59c4a8c82f2c8a522dbe754a8bc8d08c85c491"
+            ],
+            "version": "==0.6.2"
+        }
+    },
+    "develop": {}
+}

README.md

@@ -4,38 +4,54 @@
 
 [![Build Status](https://travis-ci.org/heroku/heroku-buildpack-python.svg?branch=master)](https://travis-ci.org/heroku/heroku-buildpack-python)
 
-This is the official [Heroku buildpack](https://devcenter.heroku.com/articles/buildpacks) for Python apps, powered by [pip](https://pip.pypa.io/) and other excellent software.
+This is the official [Heroku buildpack](https://devcenter.heroku.com/articles/buildpacks) for Python apps.
 
-Recommended web frameworks include **Django** and **Flask**. The recommended webserver is **Gunicorn**. There are no restrictions around what software can be used (as long as it's pip-installable). Web processes must bind to `$PORT`, and only the HTTP protocol is permitted for incoming connections.
+Recommended web frameworks include **Django** and **Flask**, among others. The recommended webserver is **Gunicorn**. There are no restrictions around what software can be used (as long as it's pip-installable). Web processes must bind to `$PORT`, and only the HTTP protocol is permitted for incoming connections.
 
-Some Python packages with obscure C dependencies are [not compatible](https://devcenter.heroku.com/articles/python-c-deps).
+Python packages with C dependencies that are not [available on the stack image](https://devcenter.heroku.com/articles/stack-packages) are generally not supported, unless `manylinux` wheels are provided by the package maintainers (common). For recommended solutions, check out [this article](https://devcenter.heroku.com/articles/python-c-deps) for more information.
 
 See it in Action
 ----------------
+```
+$ ls
+my-application		requirements.txt	runtime.txt
 
-Deploying a Python application couldn't be easier:
+$ git push heroku master
+Counting objects: 4, done.
+Delta compression using up to 8 threads.
+Compressing objects: 100% (2/2), done.
+Writing objects: 100% (4/4), 276 bytes | 276.00 KiB/s, done.
+Total 4 (delta 0), reused 0 (delta 0)
+remote: Compressing source files... done.
+remote: Building source:
+remote:
+remote: -----> Python app detected
+remote: -----> Installing python-3.7.4
+remote: -----> Installing pip
+remote: -----> Installing SQLite3
+remote: -----> Installing requirements with pip
+remote:        Collecting flask (from -r /tmp/build_c2c067ef79ff14c9bf1aed6796f9ed1f/requirements.txt (line 1))
+remote:          Downloading ...
+remote:        Installing collected packages: Werkzeug, click, MarkupSafe, Jinja2, itsdangerous, flask
+remote:        Successfully installed Jinja2-2.10 MarkupSafe-1.1.0 Werkzeug-0.14.1 click-7.0 flask-1.0.2 itsdangerous-1.1.0
+remote:
+remote: -----> Discovering process types
+remote:        Procfile declares types -> (none)
+remote:
+```
 
-    $ ls
-    Procfile  requirements.txt  web.py
+A `requirements.txt` must be present at the root of your application's repository to deploy.
 
-    $ heroku create --buildpack heroku/python
+To specify your python version, you also need a `runtime.txt` file - unless you are using the default Python runtime version.
 
-    $ git push heroku master
-    ...
-    -----> Python app detected
-    -----> Installing python-3.6.2
-         $ pip install -r requirements.txt
-           Collecting requests (from -r requirements.txt (line 1))
-             Downloading requests-2.12.4-py2.py3-none-any.whl (576KB)
-           Installing collected packages: requests
-           Successfully installed requests-2.12.4
+Current default Python Runtime: Python 3.6.9
 
-    -----> Discovering process types
-           Procfile declares types -> (none)
+Alternatively, you can provide a `setup.py` file, or a `Pipfile`. Using `Pipenv` will generate `runtime.txt` based on `python-version` at build time.
 
-A `requirements.txt` file must be present at the root of your application's repository.
+Specify a Buildpack Version
+---------------------------
 
-You can also specify the latest production release of this buildpack for upcoming builds of an existing application:
+You can specify the latest production release of this buildpack for upcoming builds of an existing application:
 
     $ heroku buildpacks:set heroku/python
 
@@ -43,14 +59,30 @@ You can also specify the latest production release of this buildpack for upcomin
 Specify a Python Runtime
 ------------------------
 
-Specific versions of the Python runtime can be specified with a `runtime.txt` file:
+Supported runtime options include:
 
-    $ cat runtime.txt
-    python-2.7.13
+- `python-3.7.4`
+- `python-3.6.9`
+- `python-2.7.17`
 
-Runtime options include:
+## Tests
 
-- `python-3.6.2`
-- `python-2.7.13`
-- `pypy-5.7.1` (unsupported, experimental)
-- `pypy3-5.5.1` (unsupported, experimental)
+The buildpack tests use [Docker](https://www.docker.com/) to simulate
+Heroku's [stack images.](https://devcenter.heroku.com/articles/stack)
+
+To run the test suite:
+
+```
+make test
+```
+
+Or to test in a particular stack:
+
+```
+make test-heroku-18
+make test-heroku-16
+```
+
+The tests are run via the vendored
+[shunit2](https://github.com/kward/shunit2)
+test framework.

Rakefile

@@ -0,0 +1 @@
+require 'hatchet/tasks'

bin/compile

@@ -15,55 +15,103 @@
 # Fail fast and fail hard.
 set -eo pipefail
 
-# Standard Library.
+# Boostrap the Buildpack Standard Library.
 export BPLOG_PREFIX="buildpack.python"
 export BUILDPACK_LOG_FILE=${BUILDPACK_LOG_FILE:-/dev/null}
 
 [ "$BUILDPACK_XTRACE" ] && set -o xtrace
 
-# Prepend proper path for virtualenv hackery. This will be deprecated soon.
+# Prepend proper path for old-school virtualenv hackery.
+# This may not be neccessary.
 export PATH=:/usr/local/bin:$PATH
 
-# Paths.
-BIN_DIR=$(cd $(dirname $0); pwd) # absolute path
-ROOT_DIR=$(dirname $BIN_DIR)
+# Setup Path variables, for later use in the Buildpack.
+BIN_DIR=$(cd "$(dirname "$0")"; pwd) # absolute path
+ROOT_DIR=$(dirname "$BIN_DIR")
 BUILD_DIR=$1
 CACHE_DIR=$2
 ENV_DIR=$3
 
-# Python defaults
-DEFAULT_PYTHON_VERSION="python-3.6.2"
-DEFAULT_PYTHON_STACK="cedar-14"
-PYTHON_EXE="/app/.heroku/python/bin/python"
-PIP_VERSION="9.0.1"
+# Export Path variables, for use in sub-scripts.
+export BUILD_DIR CACHE_DIR ENV_DIR
 
-# Common Problem Warnings
-export WARNINGS_LOG=$(mktemp)
+# Set the Buildpack's internet target for downloading Python distributions.
+# The user can provide BUILDPACK_VENDOR_URL to specify a custom target.
+# Note: this is designed for non-Heroku use, as it does not use the user-provided
+# environment variable mechanism (the ENV_DIR).
+VENDOR_URL="https://lang-python.s3.amazonaws.com/$STACK"
+if [[ -n ${BUILDPACK_VENDOR_URL:-} ]]; then
+    VENDOR_URL="$BUILDPACK_VENDOR_URL"
+elif [[ -n ${USE_STAGING_BINARIES} ]]; then
+    VENDOR_URL="$USE_STAGING_BINARIES/$STACK"
+fi
+export VENDOR_URL
+
+# Default Python Versions
+# shellcheck source=bin/default_pythons
+source "$BIN_DIR/default_pythons"
+
+# Supported Python Branches
+PY38="python-3.8"
+PY37="python-3.7"
+PY36="python-3.6"
+PY35="python-3.5"
+PY34="python-3.4"
+PY27="python-2.7"
+
+# Which stack is used (for binary downloading), if none is provided (e.g. outside of Heroku)?
+DEFAULT_PYTHON_STACK="cedar-14"
+# If pip doesn't match this version (the version we install), run the installer.
+PIP_UPDATE="9.0.2"
+
+export DEFAULT_PYTHON_STACK PIP_UPDATE
+export PY37 PY36 PY35 PY27 PY34
+
+# Common Problem Warnings:
+# This section creates a temporary file in which to stick the output of `pip install`.
+# The `warnings` subscript then greps through this for common problems and guides
+# the user towards resolution of known issues.
+WARNINGS_LOG=$(mktemp)
+export WARNINGS_LOG
 export RECOMMENDED_PYTHON_VERSION=$DEFAULT_PYTHON_VERSION
 
-# Setup vendored tools and pip-pop (pip-diff)
+# The buildpack ships with a few executable tools (e.g. pip-grep, etc).
+# This installs them into the path, so we can execute them directly.
 export PATH=$PATH:$ROOT_DIR/vendor/:$ROOT_DIR/vendor/pip-pop
 
-# Support Anvil Build_IDs
+# Set environment variables if they weren't set by the platform.
+# Note: this is legacy, for a deprecated build system known as Anvil.
+# This can likely be removed, with caution.
 [ ! "$SLUG_ID" ] && SLUG_ID="defaultslug"
 [ ! "$REQUEST_ID" ] && REQUEST_ID=$SLUG_ID
 [ ! "$STACK" ] && STACK=$DEFAULT_PYTHON_STACK
 
-# Sanitizing environment variables.
+# Sanitize externally-provided environment variables:
+# The following environment variables are either problematic or simply unneccessary
+# for the buildpack to have knowledge of, so we unset them, to keep the environment
+# as clean and pristine as possible.
 unset GIT_DIR PYTHONHOME PYTHONPATH
 unset RECEIVE_DATA RUN_KEY BUILD_INFO DEPLOY LOG_TOKEN
 unset CYTOKINE_LOG_FILE GEM_PATH
 
-# Syntax sugar.
-source $BIN_DIR/utils
+# Import the utils script, which contains helper functions used throughout the buildpack.
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
 
-# Import collection of warnings.
-source $BIN_DIR/warnings
+# Import the warnings script, which contains the `pip install` user warning mechanisms
+# (mentioned and explained above)
+# shellcheck source=bin/warnings
+source "$BIN_DIR/warnings"
 
-# we need to put a bunch of symlinks in there later
+# Make the directory in which we will create symlinks from the temporary build directory
+# to `/app`.
+# Symlinks are required, since Python is not a portable installation.
+# More on this topic later.
 mkdir -p /app/.heroku
 
-# Set up outputs under new context
+# This buildpack programatically generates (or simply copies) a number of files for
+# buildpack machinery: an export script, and a number of `.profile.d` scripts. This
+# section declares the locations of those files and targets.
 PROFILE_PATH="$BUILD_DIR/.profile.d/python.sh"
 EXPORT_PATH="$BIN_DIR/../export"
 GUNICORN_PROFILE_PATH="$BUILD_DIR/.profile.d/python.gunicorn.sh"
@@ -72,169 +120,270 @@ WEB_CONCURRENCY_PROFILE_PATH="$BUILD_DIR/.profile.d/WEB_CONCURRENCY.sh"
 # We'll need to send these statics to other scripts we `source`.
 export BUILD_DIR CACHE_DIR BIN_DIR PROFILE_PATH EXPORT_PATH
 
-# Prepend proper environment variables for Python use.
+# Python Environment Variables
+# Set Python-specific environment variables, for running Python within the buildpack.
+# Notes on each variable included.
+
+# PATH is relatively obvious, we need to be able to execute 'python'.
 export PATH=/app/.heroku/python/bin:/app/.heroku/vendor/bin:$PATH
+# Tell Python to not buffer it's stdin/stdout.
 export PYTHONUNBUFFERED=1
+# Set the locale to a well-known and expected standard.
 export LANG=en_US.UTF-8
+# `~/.heroku/vendor` is an place where the buildpack may stick pre-build binaries for known
+# C dependencies (e.g. libmemcached on cedar-14). This section configures Python (GCC, more specifically)
+# and pip to automatically include these paths when building binaries.
 export C_INCLUDE_PATH=/app/.heroku/vendor/include:/app/.heroku/python/include:$C_INCLUDE_PATH
 export CPLUS_INCLUDE_PATH=/app/.heroku/vendor/include:/app/.heroku/python/include:$CPLUS_INCLUDE_PATH
 export LIBRARY_PATH=/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LIBRARY_PATH
 export LD_LIBRARY_PATH=/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LD_LIBRARY_PATH
 export PKG_CONFIG_PATH=/app/.heroku/vendor/lib/pkg-config:/app/.heroku/python/lib/pkg-config:$PKG_CONFIG_PATH
 
+# The Application Code
+# --------------------
+
 # Switch to the repo's context.
-cd $BUILD_DIR
+cd "$BUILD_DIR"
 
-# Warn for lack of Procfile.
-if [[ ! -f Procfile ]]; then
-  puts-warn 'Warning: Your application is missing a Procfile. This file tells Heroku how to run your application.'
-  puts-warn 'Learn more: https://devcenter.heroku.com/articles/procfile'
-fi
+# The Cache
+# ---------
 
-# Prepare the cache.
-mkdir -p $CACHE_DIR
+# The workflow for the Python Buildpack's cache is as follows:
+#
+# - `~/.heroku/{known-paths}` are copied from the cache into the slug.
+# - The build is executed, modifying `~/.heroku/{known-paths}`.
+# - Once the build is complete, `~/.heroku/{known-paths}` is copied back into the cache.
+
+# Create the cache directory, if it doesn't exist.
+mkdir -p "$CACHE_DIR"
 
 # Restore old artifacts from the cache.
 mkdir -p .heroku
 
-cp -R $CACHE_DIR/.heroku/python .heroku/ &> /dev/null || true
-cp -R $CACHE_DIR/.heroku/python-stack .heroku/ &> /dev/null || true
-cp -R $CACHE_DIR/.heroku/python-version .heroku/ &> /dev/null || true
-cp -R $CACHE_DIR/.heroku/vendor .heroku/ &> /dev/null || true
-if [[ -d $CACHE_DIR/.heroku/src ]]; then
-  cp -R $CACHE_DIR/.heroku/src .heroku/ &> /dev/null || true
+# The Python installation.
+cp -R "$CACHE_DIR/.heroku/python" .heroku/ &> /dev/null || true
+# A plain text file which contains the current stack being used (used for cache busting).
+cp -R "$CACHE_DIR/.heroku/python-stack" .heroku/ &> /dev/null || true
+# A plain text file which contains the current python version being used (used for cache busting).
+cp -R "$CACHE_DIR/.heroku/python-version" .heroku/ &> /dev/null || true
+# A plain text file which contains the current sqlite3 version being used (used for cache busting).
+cp -R "$CACHE_DIR/.heroku/python-sqlite3-version" .heroku/ &> /dev/null || true
+# Any pre-compiled binaries, provided by the buildpack.
+cp -R "$CACHE_DIR/.heroku/vendor" .heroku/ &> /dev/null || true
+# "editable" installations of code repositories, via pip or pipenv.
+if [[ -d "$CACHE_DIR/.heroku/src" ]]; then
+  cp -R "$CACHE_DIR/.heroku/src" .heroku/ &> /dev/null || true
 fi
 
-# Experimental pre_compile hook.
-source $BIN_DIR/steps/hooks/pre_compile
+# The pre_compile hook. Customers rely on this. Don't remove it.
+# This part of the code is used to allow users to customize their build experience
+# without forking the buildpack by providing a `bin/pre_compile` script, which gets
+# run inline with the buildpack automatically.
 
-# Sticky runtimes.
-if [ -f $CACHE_DIR/.heroku/python-version ]; then
-  DEFAULT_PYTHON_VERSION=$(cat $CACHE_DIR/.heroku/python-version)
+# shellcheck source=bin/steps/hooks/pre_compile
+source "$BIN_DIR/steps/hooks/pre_compile"
+
+# Sticky runtimes. If there was a previous build, and it used a given version of Python,
+# continue to use that version of Python in perpituity (warnings will be raised if
+# they are out–of–date).
+if [ -f "$CACHE_DIR/.heroku/python-version" ]; then
+  DEFAULT_PYTHON_VERSION=$(cat "$CACHE_DIR/.heroku/python-version")
 fi
 
-# Stack fallback for non-declared caches.
-if [ -f $CACHE_DIR/.heroku/python-stack ]; then
-  CACHED_PYTHON_STACK=$(cat $CACHE_DIR/.heroku/python-stack)
+# We didn't always record the stack version. This code is in place because of that.
+if [ -f "$CACHE_DIR/.heroku/python-stack" ]; then
+  CACHED_PYTHON_STACK=$(cat "$CACHE_DIR/.heroku/python-stack")
 else
   CACHED_PYTHON_STACK=$STACK
 fi
 
-# Pipenv Python version support.
-source $BIN_DIR/steps/pipenv-python-version
+export CACHED_PYTHON_STACK
 
-# If no runtime given, assume default version.
+# Pipenv Python version support.
+# Detect the version of Python requested from a Pipfile (e.g. python_version or python_full_version).
+# Convert it to a runtime.txt file.
+
+# shellcheck source=bin/steps/pipenv-python-version
+source "$BIN_DIR/steps/pipenv-python-version"
+
+# If no runtime was provided by the user, assume the default Python runtime version.
 if [ ! -f runtime.txt ]; then
-  echo $DEFAULT_PYTHON_VERSION > runtime.txt
+  echo "$DEFAULT_PYTHON_VERSION" > runtime.txt
 fi
 
-mkdir -p $(dirname $PROFILE_PATH)
+# Create the directory for .profile.d, if it doesn't exist.
+mkdir -p "$(dirname "$PROFILE_PATH")"
+# Create the directory for editable source code installation, if it doesn't exist.
 mkdir -p /app/.heroku/src
 
+# On Heroku CI, builds happen in `/app`. Otherwise, on the Heroku platform,
+# they occur in a temp directory. Beacuse Python is not portable, we must create
+# symlinks to emulate that we are operating in `/app` during the build process.
+# This is (hopefully obviously) because apps end up running from `/app` in production.
 if [[ $BUILD_DIR != '/app' ]]; then
     # python expects to reside in /app, so set up symlinks
     # we will not remove these later so subsequent buildpacks can still invoke it
-    ln -nsf $BUILD_DIR/.heroku/python /app/.heroku/python
-    ln -nsf $BUILD_DIR/.heroku/vendor /app/.heroku/vendor
+    ln -nsf "$BUILD_DIR/.heroku/python" /app/.heroku/python
+    ln -nsf "$BUILD_DIR/.heroku/vendor" /app/.heroku/vendor
     # Note: .heroku/src is copied in later.
 fi
 
-# Install Python.
-let start=$(nowms)
-source $BIN_DIR/steps/python
+# Download / Install Python, from pre-build binaries available on Amazon S3.
+# This step also bootstraps pip / setuptools.
+(( start=$(nowms) ))
+# shellcheck source=bin/steps/python
+source "$BIN_DIR/steps/python"
 mtime "python.install.time" "${start}"
 
-# Pipenv support.
-source $BIN_DIR/steps/pipenv
+# Install Pipenv dependencies, if a Pipfile was provided.
+# shellcheck source=bin/steps/pipenv
+source "$BIN_DIR/steps/pipenv"
+
+# Uninstall removed dependencies with Pip.
+# The buildpack will automatically remove any declared dependencies (in requirements.txt)
+# that were explicitly removed. This machinery is a bit complex, but it is not complicated.
+(( start=$(nowms) ))
+# shellcheck source=bin/steps/pip-uninstall
+source "$BIN_DIR/steps/pip-uninstall"
+mtime "pip.uninstall.time" "${start}"
 
 # If no requirements.txt file given, assume `setup.py develop` is intended.
+# This allows for people to ship a setup.py application to Heroku
+# (which is rare, but I vouch that it should work!)
+
 if [ ! -f requirements.txt ] && [ ! -f Pipfile ]; then
   echo "-e ." > requirements.txt
 fi
 
 # Fix egg-links.
-source $BIN_DIR/steps/eggpath-fix
+# Because we're installing things into a different path than we're running them (temp dir vs app dir),
+# We must re-write all of Python's eggpath links to target the proper directory.
+# shellcheck source=bin/steps/eggpath-fix
+source "$BIN_DIR/steps/eggpath-fix"
 
 # Mercurial support.
-source $BIN_DIR/steps/mercurial
+# If a customer appears to be using mercurial for dependency resolution, we install it first.
+# Note: this only applies to pip, not pipenv. This can likely be removed, over time. Measure it first.
+# shellcheck source=bin/steps/mercurial
+source "$BIN_DIR/steps/mercurial"
 
 # Pylibmc support.
-source $BIN_DIR/steps/pylibmc
+# On cedar-14, libmemcached was not available. The buildpack provides its own version, instead.
+# shellcheck source=bin/steps/pylibmc
+source "$BIN_DIR/steps/pylibmc"
 
-# Libffi support.
-source $BIN_DIR/steps/cryptography
-
-# Support for Geo libraries.
-sub-env $BIN_DIR/steps/geo-libs
+# Support for Geo libraries. This is deprecated functionality, only functional on cedar-14.
+# It is undocumented.
+# shellcheck source=bin/steps/geo-libs
+sub_env "$BIN_DIR/steps/geo-libs"
 
 # GDAL support.
-source $BIN_DIR/steps/gdal
+# This is part of the Geo support.
+# shellcheck source=bin/steps/gdal
+source "$BIN_DIR/steps/gdal"
 
-# Uninstall removed dependencies with Pip.
-let start=$(nowms)
-source $BIN_DIR/steps/pip-uninstall
-mtime "pip.uninstall.time" "${start}"
+# SQLite3 support.
+# This sets up and installs sqlite3 dev headers and the sqlite3 binary but not the
+# libsqlite3-0 library since that exists on the stack image.
+# Note: This only applies to Python 2.7.15+ and Python 3.6.6+
+(( start=$(nowms) ))
+# shellcheck source=bin/steps/sqlite3
+source "$BIN_DIR/steps/sqlite3"
+buildpack_sqlite3_install
+mtime "sqlite3.install.time" "${start}"
 
-# Install dependencies with Pip (where the magic happens).
-let start=$(nowms)
-source $BIN_DIR/steps/pip-install
+# pip install
+# -----------
+
+# Install dependencies with pip (where the magic happens).
+(( start=$(nowms) ))
+# shellcheck source=bin/steps/pip-install
+source "$BIN_DIR/steps/pip-install"
 mtime "pip.install.time" "${start}"
 
 # Support for NLTK corpora.
-let start=$(nowms)
-sub-env $BIN_DIR/steps/nltk
+# Note: this may only work on Python 2.7. I don't think many customers use this functionality,
+# and it should probably be undocumented.
+# (there's an import error on 3.6 that should hopefully be fixed upstream at some point)
+(( start=$(nowms) ))
+sub_env "$BIN_DIR/steps/nltk"
 mtime "nltk.download.time" "${start}"
 
-# Support for pip install -e.
+# Support for editable installations. Here, we are copying pip–created src directory,
+# and copying it into the proper place (the logical place to do this was early, but it must be done here).
 # In CI, $BUILD_DIR is /app.
 if [[ ! "$BUILD_DIR" == "/app" ]]; then
-  rm -fr $BUILD_DIR/.heroku/src
-  deep-cp /app/.heroku/src $BUILD_DIR/.heroku/src
+  rm -fr "$BUILD_DIR/.heroku/src"
+  deep-cp /app/.heroku/src "$BUILD_DIR/.heroku/src"
 fi
 
 
 # Django collectstatic support.
-let start=$(nowms)
-sub-env $BIN_DIR/steps/collectstatic
+# The buildpack automatically runs collectstatic for Django applications.
+# This is the cause for the majority of build failures on the Python platform.
+# These failures are intentional — if collectstatic (which can be tricky, at times) fails,
+# your build fails.
+(( start=$(nowms) ))
+sub_env "$BIN_DIR/steps/collectstatic"
 mtime "collectstatic.time" "${start}"
 
-# Create .profile script for application runtime environment variables.
-set-env PATH '$HOME/.heroku/python/bin:$PATH'
-set-env PYTHONUNBUFFERED true
-set-env PYTHONHOME /app/.heroku/python
-set-env LIBRARY_PATH '/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LIBRARY_PATH'
-set-env LD_LIBRARY_PATH '/app/.heroku/vendor/lib:/app/.heroku/python/lib:$LD_LIBRARY_PATH'
-set-default-env LANG en_US.UTF-8
-set-default-env PYTHONHASHSEED random
-set-default-env PYTHONPATH /app/
+
+# Progamatically create .profile.d script for application runtime environment variables.
+
+# Set the PATH to include Python / pip / pipenv / etc.
+set_env PATH "\$HOME/.heroku/python/bin:\$PATH"
+# Tell Python to run in unbuffered mode.
+set_env PYTHONUNBUFFERED true
+# Tell Python where it lives.
+set_env PYTHONHOME "\$HOME/.heroku/python"
+# Set variables for C libraries.
+set_env LIBRARY_PATH "\$HOME/.heroku/vendor/lib:\$HOME/.heroku/python/lib:\$LIBRARY_PATH"
+set_env LD_LIBRARY_PATH "\$HOME/.heroku/vendor/lib:\$HOME/.heroku/python/lib:\$LD_LIBRARY_PATH"
+# Locale.
+set_default_env LANG en_US.UTF-8
+# The Python hash seed is set to random.
+set_default_env PYTHONHASHSEED random
+# Tell Python to look for Python modules in the /app dir. Don't change this.
+set_default_env PYTHONPATH "\$HOME"
+
+# Python expects to be in /app, if at runtime, it is not, set
+# up symlinks… this can occur when the subdir buildpack is used.
+cat <<EOT >> "$PROFILE_PATH"
+if [[ \$HOME != "/app" ]]; then
+    mkdir -p /app/.heroku
+    ln -nsf "\$HOME/.heroku/python" /app/.heroku/python
+    ln -nsf "\$HOME/.heroku/vendor" /app/.heroku/vendor
+fi
+EOT
 
 # Install sane-default script for $WEB_CONCURRENCY and $FORWARDED_ALLOW_IPS.
-cp $ROOT_DIR/vendor/WEB_CONCURRENCY.sh $WEB_CONCURRENCY_PROFILE_PATH
-cp $ROOT_DIR/vendor/python.gunicorn.sh $GUNICORN_PROFILE_PATH
+cp "$ROOT_DIR/vendor/WEB_CONCURRENCY.sh" "$WEB_CONCURRENCY_PROFILE_PATH"
+cp "$ROOT_DIR/vendor/python.gunicorn.sh" "$GUNICORN_PROFILE_PATH"
 
-
-# Experimental post_compile hook.
-source $BIN_DIR/steps/hooks/post_compile
+# Experimental post_compile hook. Don't remove this.
+# shellcheck source=bin/steps/hooks/post_compile
+source "$BIN_DIR/steps/hooks/post_compile"
 
 # Fix egg-links, again.
-source $BIN_DIR/steps/eggpath-fix2
+# shellcheck source=bin/steps/eggpath-fix2
+source "$BIN_DIR/steps/eggpath-fix2"
 
-# Store new artifacts in cache.
+# Store new artifacts in the cache.
+rm -rf "$CACHE_DIR/.heroku/python"
+rm -rf "$CACHE_DIR/.heroku/python-version"
+rm -rf "$CACHE_DIR/.heroku/python-stack"
+rm -rf "$CACHE_DIR/.heroku/vendor"
+rm -rf "$CACHE_DIR/.heroku/src"
 
-rm -rf $CACHE_DIR/.heroku/python
-rm -rf $CACHE_DIR/.heroku/python-version
-rm -rf $CACHE_DIR/.heroku/python-stack
-rm -rf $CACHE_DIR/.heroku/vendor
-rm -rf $CACHE_DIR/.heroku/src
-
-mkdir -p $CACHE_DIR/.heroku
-cp -R .heroku/python $CACHE_DIR/.heroku/
-cp -R .heroku/python-version $CACHE_DIR/.heroku/
-cp -R .heroku/python-stack $CACHE_DIR/.heroku/ &> /dev/null || true
-cp -R .heroku/vendor $CACHE_DIR/.heroku/ &> /dev/null || true
+mkdir -p "$CACHE_DIR/.heroku"
+cp -R .heroku/python "$CACHE_DIR/.heroku/"
+cp -R .heroku/python-version "$CACHE_DIR/.heroku/"
+cp -R .heroku/python-stack "$CACHE_DIR/.heroku/" &> /dev/null || true
+cp -R .heroku/vendor "$CACHE_DIR/.heroku/" &> /dev/null || true
 if [[ -d .heroku/src ]]; then
-  cp -R .heroku/src $CACHE_DIR/.heroku/ &> /dev/null || true
+  cp -R .heroku/src "$CACHE_DIR/.heroku/" &> /dev/null || true
 fi
 
 # Measure the size of the Python installation.
+# shellcheck disable=SC2119
 mmeasure 'python.size' "$(measure-size)"

bin/default_pythons

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+DEFAULT_PYTHON_VERSION="python-3.6.9"
+LATEST_38="python-3.8.0"
+LATEST_37="python-3.7.5"
+LATEST_36="python-3.6.9"
+LATEST_35="python-3.5.7"
+LATEST_34="python-3.4.10"
+LATEST_27="python-2.7.17"
+
+export DEFAULT_PYTHON_VERSION LATEST_38 LATEST_37 LATEST_36 LATEST_35 LATEST_34 LATEST_27

bin/detect

@@ -15,7 +15,7 @@
 BUILD_DIR=$1
 
 # Exit early if app is clearly not Python.
-if [ ! -f $BUILD_DIR/requirements.txt ] && [ ! -f $BUILD_DIR/setup.py ] && [ ! -f $BUILD_DIR/Pipfile ]; then
+if [ ! -f "$BUILD_DIR/requirements.txt" ] && [ ! -f "$BUILD_DIR/setup.py" ] && [ ! -f "$BUILD_DIR/Pipfile" ]; then
   exit 1
 fi
 

bin/release

@@ -1,10 +1,9 @@
 #!/usr/bin/env bash
 # bin/release <build-dir>
 
-BIN_DIR=$(cd $(dirname $0); pwd) # absolute path
 BUILD_DIR=$1
 
-MANAGE_FILE=$(cd $BUILD_DIR && find . -maxdepth 3 -type f -name 'manage.py' | head -1)
+MANAGE_FILE=$(cd "$BUILD_DIR" && find . -maxdepth 3 -type f -name 'manage.py' | head -1)
 MANAGE_FILE=${MANAGE_FILE:2}
 
 cat <<EOF

bin/steps/collectstatic

@@ -10,7 +10,8 @@
 #   - $DISABLE_COLLECTSTATIC: disables this functionality.
 #   - $DEBUG_COLLECTSTATIC: upon failure, print out environment variables.
 
-source $BIN_DIR/utils
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
 
 # Location of 'manage.py', if it exists.
 MANAGE_FILE=$(find . -maxdepth 3 -type f -name 'manage.py' -printf '%d\t%P\n' | sort -nk1 | cut -f2 | head -1)
@@ -29,13 +30,35 @@ if [ ! "$DISABLE_COLLECTSTATIC" ] && [ -f "$MANAGE_FILE" ] && [ "$DJANGO_INSTALL
     puts-step "$ python $MANAGE_FILE collectstatic --noinput"
 
     # Run collectstatic, cleanup some of the noisy output.
-    python $MANAGE_FILE collectstatic --noinput --traceback 2>&1 | sed '/^Post-processed/d;/^Copying/d;/^$/d' | indent
+    PYTHONPATH=${PYTHONPATH:-.}
+    export PYTHONPATH
+
+    # Create a temporary file for collecting the collectstaic logs.
+    COLLECTSTATIC_LOG=$(mktemp)
+
+    python "$MANAGE_FILE" collectstatic --noinput --traceback 2>&1 | tee "$COLLECTSTATIC_LOG" | sed '/^Post-processed/d;/^Copying/d;/^$/d' | indent
     COLLECTSTATIC_STATUS="${PIPESTATUS[0]}"
 
     set -e
 
     # Display a warning if collectstatic failed.
-    [ $COLLECTSTATIC_STATUS -ne 0 ] && {
+    [ "$COLLECTSTATIC_STATUS" -ne 0 ] && {
+
+        if grep -q 'SyntaxError' "$COLLECTSTATIC_LOG"; then
+            mcount "failure.collectstatic.syntax-error"
+
+        elif grep -q 'ImproperlyConfigured' "$COLLECTSTATIC_LOG"; then
+            mcount "failure.collectstatic.improper-configuration"
+
+        elif grep -q 'The CSS file' "$COLLECTSTATIC_LOG"; then
+            mcount "failure.collectstatic.fancy-references"
+
+        elif grep -q 'OSError' "$COLLECTSTATIC_LOG"; then
+            mcount "failure.collectstatic.missing-file"
+
+        else
+            mcount "failure.collectstatic.other"
+        fi
 
         echo
         echo " !     Error while running '$ python $MANAGE_FILE collectstatic --noinput'."

bin/steps/cryptography

@@ -1,31 +0,0 @@
-#!/usr/bin/env bash
-
-# This script serves as the Cryptography build step of the
-# [**Python Buildpack**](https://github.com/heroku/heroku-buildpack-python)
-# compiler.
-#
-# A [buildpack](https://devcenter.heroku.com/articles/buildpacks) is an
-# adapter between a Python application and Heroku's runtime.
-#
-# This script is invoked by [`bin/compile`](/).
-
-# The location of the pre-compiled libffi binary.
-VENDORED_LIBFFI="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/libffi.tar.gz"
-
-PKG_CONFIG_PATH="/app/.heroku/vendor/lib/pkgconfig:$PKG_CONFIG_PATH"
-
-# Syntax sugar.
-source $BIN_DIR/utils
-
-# If a package using cffi exists within requirements, use vendored libffi.
-if (pip-grep -s requirements.txt argon2-cffi bcrypt cffi cryptography django[argon2] Django[argon2] django[bcrypt] Django[bcrypt] PyNaCl pyOpenSSL PyOpenSSL requests[security] misaka &> /dev/null) then
-
-  if [ ! -d ".heroku/vendor/lib/libffi-3.1" ]; then
-    echo "-----> Noticed cffi. Bootstrapping libffi."
-    mkdir -p .heroku/vendor
-    # Download and extract libffi into target vendor directory.
-    curl $VENDORED_LIBFFI -s | tar zxv -C .heroku/vendor &> /dev/null
-  fi
-
-  export LIBFFI=$(pwd)/vendor
-fi

bin/steps/eggpath-fix

@@ -1,3 +1,5 @@
+#!/usr/bin/env bash
+
 set +e
 # delete any existing egg links, to uninstall exisisting installations.
 find .heroku/python/lib/python*/site-packages/ -name "*.egg-link" -delete 2> /dev/null

bin/steps/eggpath-fix2

@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 set +e
 # rewrite build dir in egg links to /app so things are found at runtime
 find .heroku/python/lib/python*/site-packages/ -name "*.pth" -print0 2> /dev/null | xargs -r -0 -n 1 sed -i -e "s#$(pwd)#/app#" &> /dev/null

bin/steps/gdal

@@ -10,12 +10,13 @@
 # This script is invoked by [`bin/compile`](/).
 
 # The location of the pre-compiled cryptography binary.
-VENDORED_GDAL="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/gdal.tar.gz"
+VENDORED_GDAL="${VENDOR_URL}/libraries/vendor/gdal.tar.gz"
 
 PKG_CONFIG_PATH="/app/.heroku/vendor/lib/pkgconfig:$PKG_CONFIG_PATH"
 
 # Syntax sugar.
-source $BIN_DIR/utils
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
 
 # If GDAL exists within requirements, use vendored gdal.
 if (pip-grep -s requirements.txt GDAL gdal pygdal &> /dev/null) then
@@ -24,9 +25,10 @@ if (pip-grep -s requirements.txt GDAL gdal pygdal &> /dev/null) then
     echo "-----> Noticed GDAL. Bootstrapping gdal."
     mkdir -p .heroku/vendor
     # Download and extract cryptography into target vendor directory.
-    curl $VENDORED_GDAL -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$VENDORED_GDAL" -s | tar zxv -C .heroku/vendor &> /dev/null
+    mcount "steps.vendor.gdal"
   fi
 
-  export GDAL=$(pwd)/vendor
+  GDAL=$(pwd)/vendor
+  export GDAL
 fi
-

bin/steps/geo-libs

@@ -10,27 +10,43 @@
 # This script is invoked by [`bin/compile`](/).
 
 # The location of the pre-compiled cryptography binary.
-VENDORED_GDAL="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/gdal.tar.gz"
-VENDORED_GEOS="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/geos.tar.gz"
-VENDORED_PROJ="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/proj.tar.gz"
+VENDORED_GDAL="${VENDOR_URL}/libraries/vendor/gdal.tar.gz"
+VENDORED_GEOS="${VENDOR_URL}/libraries/vendor/geos.tar.gz"
+VENDORED_PROJ="${VENDOR_URL}/libraries/vendor/proj.tar.gz"
 
 PKG_CONFIG_PATH="/app/.heroku/vendor/lib/pkgconfig:$PKG_CONFIG_PATH"
 
 # Syntax sugar.
-source $BIN_DIR/utils
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
 
 # If GDAL exists within requirements, use vendored gdal.
 if [[ "$BUILD_WITH_GEO_LIBRARIES" ]]; then
+  mcount "buildvar.BUILD_WITH_GEO_LIBRARIES"
 
   if [ ! -f ".heroku/vendor/bin/proj" ]; then
     echo "-----> Bootstrapping gdal, geos, proj."
     mkdir -p .heroku/vendor
     # Download and extract cryptography into target vendor directory.
-    curl $VENDORED_GDAL -s | tar zxv -C .heroku/vendor &> /dev/null
-    curl $VENDORED_GEOS -s | tar zxv -C .heroku/vendor &> /dev/null
-    curl $VENDORED_PROJ -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$VENDORED_GDAL" -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$VENDORED_GEOS" -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$VENDORED_PROJ" -s | tar zxv -C .heroku/vendor &> /dev/null
+
+    mcount "steps.vendor.geo_libs"
+    # Copy libjasper from build image to slug.
+    if [[ "$STACK" == "heroku-16" ]]; then
+      cp /usr/lib/x86_64-linux-gnu/libjasper.so* ".heroku/vendor/lib/."
+      mcount "steps.vendor.libjasper"
+    fi
+
   fi
 
-  export GDAL=$(pwd)/vendor
+  GDAL=$(pwd)/vendor
+  export GDAL
+  # set path for post_compile hooks
+  export GDAL_LIBRARY_PATH="$BUILD_DIR/.heroku/vendor/lib/libgdal.so"
+  export GEOS_LIBRARY_PATH="$BUILD_DIR/.heroku/vendor/lib/libgeos_c.so"
+  # set path for runtime environmeht
+  set_env GDAL_LIBRARY_PATH "/app/.heroku/vendor/lib/libgdal.so"
+  set_env GEOS_LIBRARY_PATH "/app/.heroku/vendor/lib/libgeos_c.so"
 fi
-

bin/steps/hooks/post_compile

@@ -3,5 +3,5 @@
 if [ -f bin/post_compile ]; then
     echo "-----> Running post-compile hook"
     chmod +x bin/post_compile
-    sub-env bin/post_compile
+    sub_env bin/post_compile
 fi

bin/steps/hooks/pre_compile

@@ -3,5 +3,5 @@
 if [ -f bin/pre_compile ]; then
     echo "-----> Running pre-compile hook"
     chmod +x bin/pre_compile
-    sub-env bin/pre_compile
+    sub_env bin/pre_compile
 fi

bin/steps/mercurial

@@ -1,4 +1,9 @@
+#!/usr/bin/env bash
+
 # Install Mercurial if it appears to be required.
-if (grep -Fiq "hg+" requirements.txt) then
-    /app/.heroku/python/bin/pip install  mercurial | cleanup | indent
+if [[ -f "requirements.txt" ]]; then
+	if (grep -Fiq "hg+" requirements.txt) then
+		/app/.heroku/python/bin/pip install  mercurial | cleanup | indent
+		mcount "steps.mercurial"
+	fi
 fi

bin/steps/nltk

@@ -10,21 +10,27 @@
 # This script is invoked by [`bin/compile`](/).
 
 # Syntax sugar.
-source $BIN_DIR/utils
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
 
 # Check that nltk was installed by pip, otherwise obviously not needed
-python -m nltk.downloader -h >/dev/null 2>&1
-if [ $? -eq 0 ]; then
-    puts-step "Downloading NLTK corpora..."
+if sp-grep -s nltk; then
+    puts-step "Downloading NLTK corpora…"
+
     nltk_packages_definition="$BUILD_DIR/nltk.txt"
+
     if [ -f "$nltk_packages_definition" ]; then
-        nltk_packages=$(tr "\n" " " < "$nltk_packages_definition")
-        puts-step "Downloading NLTK packages: $nltk_packages"
-        python -m nltk.downloader -d $BUILD_DIR/.heroku/python/nltk_data $nltk_packages  | indent
-        set-env NLTK_DATA "/app/.heroku/python/nltk_data"
+
+        readarray -t nltk_packages < "$nltk_packages_definition"
+        puts-step "Downloading NLTK packages: ${nltk_packages[*]}"
+
+        python -m nltk.downloader -d "$BUILD_DIR/.heroku/python/nltk_data" "${nltk_packages[@]}" | indent
+        set_env NLTK_DATA "/app/.heroku/python/nltk_data"
+
+        mcount "buildvar.NLTK_PACKAGES_DEFINITION"
+        mcount "steps.nltk"
     else
         puts-warn "'nltk.txt' not found, not downloading any corpora"
         puts-warn "Learn more: https://devcenter.heroku.com/articles/python-nltk"
     fi
 fi
-

bin/steps/pip-install

@@ -1,23 +1,68 @@
+#!/usr/bin/env bash
+
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
+
 if [ ! "$SKIP_PIP_INSTALL" ]; then
 
     # Install dependencies with Pip.
     puts-step "Installing requirements with pip"
 
+    # Set Pip env vars
+    # This reads certain environment variables set on the Heroku app config
+    # and makes them accessible to the pip install process.
+    #
+    # PIP_EXTRA_INDEX_URL allows for an alternate pypi URL to be used.
+    if [[ -r "$ENV_DIR/PIP_EXTRA_INDEX_URL" ]]; then
+        PIP_EXTRA_INDEX_URL="$(cat "$ENV_DIR/PIP_EXTRA_INDEX_URL")"
+        export PIP_EXTRA_INDEX_URL
+        mcount "buildvar.PIP_EXTRA_INDEX_URL"
+    fi
+
     set +e
-    /app/.heroku/python/bin/pip install -r $BUILD_DIR/requirements.txt --exists-action=w --src=/app/.heroku/src --disable-pip-version-check --no-cache-dir 2>&1 | tee $WARNINGS_LOG | cleanup | indent
+
+    # Set SLUGIFY_USES_TEXT_UNIDECODE, required for Airflow versions >=1.10
+    if [[ -r "$ENV_DIR/SLUGIFY_USES_TEXT_UNIDECODE" ]]; then
+        SLUGIFY_USES_TEXT_UNIDECODE="$(cat "$ENV_DIR/SLUGIFY_USES_TEXT_UNIDECODE")"
+        export SLUGIFY_USES_TEXT_UNIDECODE
+        mcount "buildvar.SLUGIFY_USES_TEXT_UNIDECODE"
+    fi
+
+    set +e
+
+    # Measure that we're using pip.
+    mcount "tool.pip"
+
+    # Count expected build failures.
+    if grep -q '==0.0.0' requirements.txt; then
+        mcount "failure.none-version"
+    fi
+
+    if [ ! -f "$BUILD_DIR/.heroku/python/bin/pip" ]; then
+        exit 1
+    fi
+    /app/.heroku/python/bin/pip install -r "$BUILD_DIR/requirements.txt" --exists-action=w --src=/app/.heroku/src --disable-pip-version-check --no-cache-dir 2>&1 | tee "$WARNINGS_LOG" | cleanup | indent
     PIP_STATUS="${PIPESTATUS[0]}"
     set -e
 
     show-warnings
 
     if [[ ! $PIP_STATUS -eq 0 ]]; then
+        mcount "failure.pip-install"
         exit 1
     fi
 
-
     # Smart Requirements handling
     cp requirements.txt .heroku/python/requirements-declared.txt
     /app/.heroku/python/bin/pip freeze --disable-pip-version-check > .heroku/python/requirements-installed.txt
 
     echo
-fi
+
+    # Install test dependencies, for CI.
+    if [ "$INSTALL_TEST" ]; then
+        if [[ -f "$1/requirements-test.txt" ]]; then
+            puts-step "Installing test dependencies…"
+            /app/.heroku/python/bin/pip install -r "$1/requirements-test.txt" --exists-action=w --src=./.heroku/src --disable-pip-version-check --no-cache-dir 2>&1 | cleanup | indent
+        fi
+    fi
+fi

bin/steps/pip-uninstall

@@ -1,18 +1,28 @@
+#!/usr/bin/env bash
+
 set +e
 # Install dependencies with Pip.
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
 
-if [[ -f .heroku/python/requirements-declared.txt ]]; then
+if [ ! "$SKIP_PIP_INSTALL" ]; then
 
-  cp .heroku/python/requirements-declared.txt requirements-declared.txt
+  if [[ -f .heroku/python/requirements-declared.txt ]]; then
 
-  pip-diff --stale requirements-declared.txt requirements.txt --exclude setuptools pip wheel > .heroku/python/requirements-stale.txt
+    cp .heroku/python/requirements-declared.txt requirements-declared.txt
 
-  rm -fr requirements-declared.txt
 
-  if [[ -s .heroku/python/requirements-stale.txt ]]; then
-    puts-step "Uninstalling stale dependencies"
-    /app/.heroku/python/bin/pip uninstall -r .heroku/python/requirements-stale.txt -y --exists-action=w | cleanup | indent
+    if ! pip-diff --stale requirements-declared.txt requirements.txt --exclude setuptools pip wheel > .heroku/python/requirements-stale.txt; then
+      mcount "failure.bad-requirements"
+    fi
+
+    rm -fr requirements-declared.txt
+
+    if [[ -s .heroku/python/requirements-stale.txt ]]; then
+      puts-step "Uninstalling stale dependencies"
+      /app/.heroku/python/bin/pip uninstall -r .heroku/python/requirements-stale.txt -y --exists-action=w --disable-pip-version-check | cleanup | indent
+    fi
   fi
-fi
 
+fi
 set -e

bin/steps/pipenv

@@ -1,19 +1,86 @@
-# Pipenv support (Generate requriements.txt with pipenv).
-if [[ -f Pipfile ]]; then
-    if [[ ! -f requirements.txt ]]; then
-        puts-step "Installing requirements with latest pipenv..."
+#!/usr/bin/env bash
 
-        # Install pipenv.
-        /app/.heroku/python/bin/pip install pipenv --upgrade &> /dev/null
+# export CLINT_FORCE_COLOR=1
+# export PIPENV_FORCE_COLOR=1
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
+set -e
 
-        # Install the dependencies.
-        /app/.heroku/python/bin/pipenv install --system 2>&1 | indent
+if [[ -f Pipfile.lock ]]; then
+    if [[ -f .heroku/python/Pipfile.lock.sha256 ]]; then
+        if [[ $(openssl dgst -sha256 Pipfile.lock) == $(cat .heroku/python/Pipfile.lock.sha256) ]]; then
+            # Measure that we're using Pipenv.
+            mcount "tool.pipenv"
+
+            # Don't skip installation of there are git deps.
+            if ! grep -q 'git' Pipfile.lock; then
+                echo "Skipping installation, as Pipfile.lock hasn't changed since last deploy." | indent
+
+                mcount "tool.pipenv"
+                export SKIP_PIPENV_INSTALL=1
+                export SKIP_PIP_INSTALL=1
+            fi
+        fi
+    fi
+fi
+
+
+if [ ! "$SKIP_PIPENV_INSTALL" ]; then
+    # Pipenv support (Generate requirements.txt with pipenv).
+    if [[ -f Pipfile ]]; then
+        # Measure that we're using Pipenv.
+        mcount "tool.pipenv"
 
         # Skip pip install, later.
         export SKIP_PIP_INSTALL=1
 
-        # Pip freeze, for compatibility.
-        /app/.heroku/python/bin/pip freeze > requirements.txt
+        # Set Pip env vars
+        # This reads certain environment variables set on the Heroku app config
+        # and makes them accessible to the pip install process.
+        #
+        # PIP_EXTRA_INDEX_URL allows for an alternate pypi URL to be used.
+        if [[ -r "$ENV_DIR/PIP_EXTRA_INDEX_URL" ]]; then
+            PIP_EXTRA_INDEX_URL="$(cat "$ENV_DIR/PIP_EXTRA_INDEX_URL")"
+            export PIP_EXTRA_INDEX_URL
+            mcount "buildvar.PIP_EXTRA_INDEX_URL"
+        fi
 
+        # Set SLUGIFY_USES_TEXT_UNIDECODE, required for Airflow versions >=1.10
+        if [[ -r "$ENV_DIR/SLUGIFY_USES_TEXT_UNIDECODE" ]]; then
+            SLUGIFY_USES_TEXT_UNIDECODE="$(cat "$ENV_DIR/SLUGIFY_USES_TEXT_UNIDECODE")"
+            export SLUGIFY_USES_TEXT_UNIDECODE
+            mcount "buildvar.SLUGIFY_USES_TEXT_UNIDECODE"
+        fi
+
+        export PIPENV_VERSION="2018.5.18"
+
+        # Install pipenv.
+        # Due to weird old pip behavior and pipenv behavior, pipenv upgrades pip
+        # to latest if only --upgrade is specified. Specify upgrade strategy to
+        # avoid this eager behavior.
+        /app/.heroku/python/bin/pip install pipenv==$PIPENV_VERSION --upgrade --upgrade-strategy only-if-needed &> /dev/null
+
+        # Install the test dependencies, for CI.
+        if [ "$INSTALL_TEST" ]; then
+            puts-step "Installing test dependencies…"
+            /app/.heroku/python/bin/pipenv install --dev --system --deploy 2>&1 | cleanup | indent
+
+        # Install the dependencies.
+        elif [[ ! -f Pipfile.lock ]]; then
+            puts-step "Installing dependencies with Pipenv $PIPENV_VERSION…"
+            /app/.heroku/python/bin/pipenv install --system --skip-lock 2>&1 | indent
+
+        else
+            pipenv-to-pip Pipfile.lock > requirements.txt
+            "$BIN_DIR/steps/pip-uninstall"
+            cp requirements.txt .heroku/python/requirements-declared.txt
+            openssl dgst -sha256 Pipfile.lock > .heroku/python/Pipfile.lock.sha256
+
+            puts-step "Installing dependencies with Pipenv $PIPENV_VERSION…"
+            /app/.heroku/python/bin/pipenv install --system --deploy 2>&1 | indent
+        fi
     fi
-fi
+else
+    export SKIP_PIP_INSTALL=1
+    pipenv-to-pip Pipfile.lock > requirements.txt
+fi

bin/steps/pipenv-python-version

@@ -1,23 +1,35 @@
+#!/usr/bin/env bash
+
 # Detect Python-version with Pipenv.
 
-if [[ -f $BUILD_DIR/Pipfile.lock ]]; then
+if [[ -f $BUILD_DIR/Pipfile ]]; then
 
     if [[ ! -f $BUILD_DIR/runtime.txt ]]; then
         if [[ ! -f $BUILD_DIR/Pipfile.lock ]]; then
-            puts-warn "No 'pipfile.lock' found! We recommend you commit this into your repository."
+            puts-warn "No 'Pipfile.lock' found! We recommend you commit this into your repository."
         fi
         if [[ -f $BUILD_DIR/Pipfile.lock ]]; then
             set +e
-            PYTHON=$(cat $BUILD_DIR/Pipfile.lock | jq '._meta.requires.python_version' -r)
+            PYTHON=$(jq -r '._meta.requires.python_full_version' "$BUILD_DIR/Pipfile.lock")
+            if [[ "$PYTHON" != "null" ]]; then
+                echo "python-$PYTHON" > "$BUILD_DIR/runtime.txt"
+            fi
             set -e
 
-            if [ "$PYTHON" = 2.7 ]; then
-                echo "python-2.7.13" > $BUILD_DIR/runtime.txt
-            fi
-            if [ "$PYTHON" = 3.6 ]; then
-                echo "python-3.6.0" > $BUILD_DIR/runtime.txt
+            if [[ "$PYTHON" == "null" ]]; then
+                PYTHON=$(jq -r '._meta.requires.python_version' "$BUILD_DIR/Pipfile.lock")
+                if [ "$PYTHON" = 2.7 ]; then
+                    echo "$LATEST_27" > "$BUILD_DIR/runtime.txt"
+                fi
+                if [ "$PYTHON" = 3.6 ]; then
+                    echo "$LATEST_36" > "$BUILD_DIR/runtime.txt"
+                fi
+                if [ "$PYTHON" = 3.7 ]; then
+                    echo "$LATEST_37" > "$BUILD_DIR/runtime.txt"
+                fi
             fi
+
+
         fi
     fi
 fi
-

bin/steps/pylibmc

@@ -9,12 +9,17 @@
 #
 # This script is invoked by [`bin/compile`](/).
 
+if [[ "$STACK" != "cedar-14" ]]; then
+    # libmemcached is pre-installed in the stack image so there is no need to vendor it.
+    return 0
+fi
+
 # The location of the pre-compiled libmemcached binary.
-VENDORED_MEMCACHED="https://lang-python.s3.amazonaws.com/$STACK/libraries/vendor/libmemcache.tar.gz"
+VENDORED_MEMCACHED="${VENDOR_URL}/libraries/vendor/libmemcache.tar.gz"
 
 # Syntax sugar.
-source $BIN_DIR/utils
-
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
 
 # If pylibmc exists within requirements, use vendored libmemcached.
 if (pip-grep -s requirements.txt pylibmc &> /dev/null) then
@@ -23,8 +28,10 @@ if (pip-grep -s requirements.txt pylibmc &> /dev/null) then
     echo "-----> Noticed pylibmc. Bootstrapping libmemcached."
     mkdir -p .heroku/vendor
     # Download and extract libmemcached into target vendor directory.
-    curl $VENDORED_MEMCACHED -s | tar zxv -C .heroku/vendor &> /dev/null
+    curl "$VENDORED_MEMCACHED" -s | tar zxv -C .heroku/vendor &> /dev/null
+    mcount "steps.vendor.pylibmc"
   fi
 
-  export LIBMEMCACHED=$(pwd)/vendor
+  LIBMEMCACHED=$(pwd)/vendor
+  export LIBMEMCACHED
 fi

bin/steps/python

@@ -1,10 +1,79 @@
+#!/usr/bin/env bash
+
 set +e
 runtime-fixer runtime.txt
 PYTHON_VERSION=$(cat runtime.txt)
 
-# Install Python.
+# The location of the pre-compiled python binary.
+VENDORED_PYTHON="${VENDOR_URL}/runtimes/$PYTHON_VERSION.tar.gz"
+
+SECURITY_UPDATE="Python has released a security update! Please consider upgrading to"
+
+# check if runtime exists
+if curl --output /dev/null --silent --head --fail "$VENDORED_PYTHON"; then
+  if [[ "$PYTHON_VERSION" == $PY38* ]]; then
+    # do things to alert the user of security release available
+    if [ "$PYTHON_VERSION" != "$LATEST_38" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_38"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY37* ]]; then
+    # do things to alert the user of security release available
+    if [ "$PYTHON_VERSION" != "$LATEST_37" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_37"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY36* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_36" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_36"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY35* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_35" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_35"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY34* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_34" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_34"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+  if [[ "$PYTHON_VERSION" == $PY27* ]]; then
+    # security update note
+    if [ "$PYTHON_VERSION" != "$LATEST_27" ]; then
+      puts-warn "$SECURITY_UPDATE" "$LATEST_27"
+      echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
+    fi
+  fi
+else
+  puts-warn "Requested runtime ($PYTHON_VERSION) is not available for this stack ($STACK)."
+  puts-warn "Aborting.  More info: https://devcenter.heroku.com/articles/python-support"
+  exit 1
+fi
+
+if [[ "$STACK" != "$CACHED_PYTHON_STACK" ]]; then
+    puts-step "Stack has changed from $CACHED_PYTHON_STACK to $STACK, clearing cache"
+    rm -fr .heroku/python-stack .heroku/python-version .heroku/python .heroku/vendor .heroku/python .heroku/python-sqlite3-version
+fi
+
+# need to clear the cache for first time installing SQLite3,
+# since the version is changing and could lead to runtime errors
+# with compiled extensions.
+if [ -d .heroku/python ] && [ ! -f .heroku/python-sqlite3-version ] && python_sqlite3_check "$PYTHON_VERSION"; then
+  puts-step "Need to update SQLite3, clearing cache"
+  rm -fr .heroku/python-stack .heroku/python-version .heroku/python .heroku/vendor
+fi
+
 if [ -f .heroku/python-version ]; then
-  if [ ! $(cat .heroku/python-version) = $PYTHON_VERSION ]; then
+  if [ ! "$(cat .heroku/python-version)" = "$PYTHON_VERSION" ]; then
       puts-step "Found $(cat .heroku/python-version), removing"
       rm -fr .heroku/python
   else
@@ -12,11 +81,6 @@ if [ -f .heroku/python-version ]; then
   fi
 fi
 
-if [ ! $STACK = $CACHED_PYTHON_STACK ]; then
-    rm -fr .heroku/python .heroku/python-stack .heroku/vendor
-    unset SKIP_INSTALL
-fi
-
 
 if [ ! "$SKIP_INSTALL" ]; then
     puts-step "Installing $PYTHON_VERSION"
@@ -24,38 +88,43 @@ if [ ! "$SKIP_INSTALL" ]; then
     # Prepare destination directory.
     mkdir -p .heroku/python
 
-    curl https://lang-python.s3.amazonaws.com/$STACK/runtimes/$PYTHON_VERSION.tar.gz -s | tar zxv -C .heroku/python &> /dev/null
     mcount "version.python.$PYTHON_VERSION"
 
-    if [[ $? != 0 ]] ; then
+    if ! curl "${VENDORED_PYTHON}" -s | tar zxv -C .heroku/python &> /dev/null; then
       puts-warn "Requested runtime ($PYTHON_VERSION) is not available for this stack ($STACK)."
       puts-warn "Aborting.  More info: https://devcenter.heroku.com/articles/python-support"
       exit 1
     fi
 
   # Record for future reference.
-  echo $PYTHON_VERSION > .heroku/python-version
-  echo $STACK > .heroku/python-stack
+  echo "$PYTHON_VERSION" > .heroku/python-version
+  echo "$STACK" > .heroku/python-stack
   FRESH_PYTHON=true
 
   hash -r
 fi
 
-# If Pip isn't up to date:
-if [ "$FRESH_PYTHON" ] || [[ ! $(pip --version) == *$PIP_VERSION* ]]; then
-  WORKING_DIR=$(pwd)
+# Heroku uses the get-pip utility maintained by the Python community to vendor Pip.
+# https://github.com/pypa/get-pip
+GETPIP="https://lang-python.s3.amazonaws.com/etc/get-pip.py"
 
-  TMPTARDIR=$(mktemp -d)
-  trap "rm -rf $TMPTARDIR" RETURN
+if ! curl -s "${GETPIP}" -o "$ROOT_DIR/get-pip.py" &> /dev/null; then
+    mcount "failure.python.get-pip"
+    echo "Failed to pull down get-pip"
+    exit 1
+fi
+
+# If Pip isn't up to date:
+if [ "$FRESH_PYTHON" ] || [[ ! $(pip --version) == *$PIP_UPDATE* ]]; then
 
   puts-step "Installing pip"
 
   # Remove old installations.
-  rm -fr /app/.heroku/python/lib/python2.7/site-packages/pip-*
-  rm -fr /app/.heroku/python/lib/python2.7/site-packages/setuptools-*
-
-  /app/.heroku/python/bin/python $ROOT_DIR/vendor/get-pip.py &> /dev/null
+  rm -fr /app/.heroku/python/lib/python*/site-packages/pip-*
+  rm -fr /app/.heroku/python/lib/python*/site-packages/setuptools-*
 
+  /app/.heroku/python/bin/python "$ROOT_DIR/get-pip.py" pip=="$PIP_UPDATE" &> /dev/null
+  /app/.heroku/python/bin/pip install "$ROOT_DIR/vendor/setuptools-39.0.1-py2.py3-none-any.whl" &> /dev/null
 fi
 
 set -e

bin/steps/sqlite3

@@ -0,0 +1,78 @@
+#!/usr/bin/env bash
+
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
+
+sqlite3_install() {
+  HEROKU_PYTHON_DIR="$1"
+  HEADERS_ONLY="$3"
+
+  mkdir -p "$HEROKU_PYTHON_DIR"
+
+  APT_CACHE_DIR="$HEROKU_PYTHON_DIR/apt/cache"
+  APT_STATE_DIR="$HEROKU_PYTHON_DIR/apt/state"
+
+  mkdir -p "$APT_CACHE_DIR/archives/partial"
+  mkdir -p "$APT_STATE_DIR/lists/partial"
+
+  APT_OPTIONS="-o debug::nolocking=true"
+  APT_OPTIONS="$APT_OPTIONS -o dir::cache=$APT_CACHE_DIR"
+  APT_OPTIONS="$APT_OPTIONS -o dir::state=$APT_STATE_DIR"
+  APT_OPTIONS="$APT_OPTIONS -o dir::etc::sourcelist=/etc/apt/sources.list"
+
+  apt-get $APT_OPTIONS update > /dev/null 2>&1
+  if [ -z "$HEADERS_ONLY" ]; then
+    apt-get $APT_OPTIONS -y -d --reinstall install libsqlite3-dev sqlite3 > /dev/null 2>&1
+  else
+    apt-get $APT_OPTIONS -y -d --reinstall install libsqlite3-dev
+  fi
+
+  find "$APT_CACHE_DIR/archives/" -name "*.deb" -exec dpkg -x {} "$HEROKU_PYTHON_DIR/sqlite3/" \;
+
+  mkdir -p "$HEROKU_PYTHON_DIR/include"
+  mkdir -p "$HEROKU_PYTHON_DIR/lib"
+
+  # remove old sqlite3 libraries/binaries
+  find "$HEROKU_PYTHON_DIR/include/" -name "sqlite3*.h" -exec rm -f {} \;
+  find "$HEROKU_PYTHON_DIR/lib/" -name "libsqlite3.*" -exec rm -f {} \;
+  rm -f "$HEROKU_PYTHON_DIR/lib/pkgconfig/sqlite3.pc"
+  rm -f "$HEROKU_PYTHON_DIR/bin/sqlite3"
+
+  # copy over sqlite3 headers & bins and setup linking against the stack image library
+  mv "$HEROKU_PYTHON_DIR/sqlite3/usr/include/"* "$HEROKU_PYTHON_DIR/include/"
+  mv "$HEROKU_PYTHON_DIR/sqlite3/usr/lib/x86_64-linux-gnu"/libsqlite3.*a "$HEROKU_PYTHON_DIR/lib/"
+  mkdir -p "$HEROKU_PYTHON_DIR/lib/pkgconfig"
+  # set the right prefix/lib directories
+  sed -e 's/prefix=\/usr/prefix=\/app\/.heroku\/python/' -e 's/\/x86_64-linux-gnu//' "$HEROKU_PYTHON_DIR/sqlite3/usr/lib/x86_64-linux-gnu/pkgconfig/sqlite3.pc" > "$HEROKU_PYTHON_DIR/lib/pkgconfig/sqlite3.pc"
+  # need to point the libsqlite3.so to the stack image library for /usr/bin/ld -lsqlite3
+  SQLITE3_LIBFILE="/usr/lib/x86_64-linux-gnu/$(readlink -n "$HEROKU_PYTHON_DIR/sqlite3/usr/lib/x86_64-linux-gnu/libsqlite3.so")"
+  ln -s "$SQLITE3_LIBFILE" "$HEROKU_PYTHON_DIR/lib/libsqlite3.so"
+  if [ -z "$HEADERS_ONLY" ]; then
+    mv "$HEROKU_PYTHON_DIR/sqlite3/usr/bin"/* "$HEROKU_PYTHON_DIR/bin/"
+  fi
+
+  # cleanup
+  rm -rf "$HEROKU_PYTHON_DIR/sqlite3/"
+  rm -rf "$HEROKU_PYTHON_DIR/apt/"
+}
+
+buildpack_sqlite3_install() {
+  HEROKU_PYTHON_DIR="$BUILD_DIR/.heroku/python"
+
+  SQLITE3_VERSION_FILE="$BUILD_DIR/.heroku/python-sqlite3-version"
+  if [ -f "$SQLITE3_VERSION_FILE" ]; then
+    INSTALLED_SQLITE3_VERSION=$(cat "$SQLITE3_VERSION_FILE")
+  fi
+
+  puts-step "Installing SQLite3"
+
+  if sqlite3_install "$BUILD_DIR/.heroku/python" ; then
+    echo "Sqlite3 successfully installed."
+    mcount "success.python.sqlite3"
+  else
+    echo "Sqlite3 failed to install."
+    mcount "failure.python.sqlite3"
+  fi
+
+  mkdir -p "$CACHE_DIR/.heroku/"
+}

bin/test-compile

@@ -1,11 +1,13 @@
 #!/usr/bin/env bash
 
 # Syntax sugar.
-BIN_DIR=$(cd $(dirname $0); pwd) # absolute path
-source $BIN_DIR/utils
+BIN_DIR=$(cd "$(dirname "$0")" || return; pwd) # absolute path
 
-DISABLE_COLLECTSTATIC=1 "$(dirname ${0:-})/compile" "$1" "$2" "$3"
+# shellcheck source=bin/utils
+source "$BIN_DIR/utils"
 
-if [[ -f "$1/requirements-test.txt" ]]; then
-    /app/.heroku/python/bin/pip install -r "$1/requirements-test.txt" --exists-action=w --src=./.heroku/src --disable-pip-version-check --no-cache-dir 2>&1 | cleanup | indent
-fi
+# Locale support for Pipenv.
+export LC_ALL=C.UTF-8
+export LANG=C.UTF-8
+
+DISABLE_COLLECTSTATIC=1 INSTALL_TEST=1 "$(dirname "${0:-}")/compile" "$1" "$2" "$3"

bin/utils

@@ -1,13 +1,15 @@
 #!/usr/bin/env bash
 shopt -s extglob
+shopt -s nullglob
 
 # The standard library.
 if [[ ! -f  /tmp/stdlib.sh ]]; then
-  curl --retry 3 -s https://lang-common.s3.amazonaws.com/buildpack-stdlib/v2/stdlib.sh > /tmp/stdlib.sh
+  curl --retry 3 -s https://lang-common.s3.amazonaws.com/buildpack-stdlib/v8/stdlib.sh > /tmp/stdlib.sh
 fi
+# shellcheck source=/dev/null
 source /tmp/stdlib.sh
 
-if [ $(uname) == Darwin ]; then
+if [ "$(uname)" == Darwin ]; then
     sed() { command sed -l "$@"; }
 else
     sed() { command sed -u "$@"; }
@@ -26,12 +28,12 @@ cleanup() {
 
 # Buildpack Steps.
 puts-step() {
-  echo "-----> $@"
+  echo "-----> $*"
 }
 
 # Buildpack Warnings.
 puts-warn() {
-  echo " !     $@"
+  echo " !     $*"
 }
 
 # Does some serious copying.
@@ -51,31 +53,45 @@ deep-cp() {
 }
 
 
-sub-env() {
-
-  WHITELIST=${2:-''}
-  BLACKLIST=${3:-'^(GIT_DIR|STACK|PYTHONHOME|LD_LIBRARY_PATH|LIBRARY_PATH|PATH)$'}
-
-  # Python-specific variables.
-  export PYHONHOME=$BUILD_DIR/.heroku/python
-  export PYTHONPATH=$BUILD_DIR/
-
-  (
-    if [ -d "$ENV_DIR" ]; then
-      for e in $(ls $ENV_DIR); do
-        echo "$e" | grep -E "$WHITELIST" | grep -qvE "$BLACKLIST" &&
-        export "$e=$(cat $ENV_DIR/$e)"
-        :
-      done
-    fi
-
-    $1
-
-  )
-}
-
 # Measure the size of the Python installation.
 measure-size() {
-  echo "$((du -s .heroku/python 2>/dev/null || echo 0) | awk '{print $1}')"
+  echo "$(du -s .heroku/python 2>/dev/null || echo 0) | awk '{print $1}')"
 }
 
+# Python version operator >
+version_gt() {
+  test "$(printf '%s\n' "$@" | sort -V | head -n 1)" != "$1";
+}
+
+# Python verison operator >=
+version_gte() {
+  if [ "$1" == "$2" ]; then
+    return 0
+  fi
+
+  version_gt "$1" "$2"
+}
+
+# Check if Python 2
+python2_check() {
+  VERSION="$1"
+
+  version_gte "$VERSION" "python-2.7.0" && version_gt "python-3.0.0" "$VERSION"
+}
+
+# Check if Python 3
+python3_check() {
+  VERSION="$1"
+
+  version_gte "$VERSION" "python-3.0.0" && version_gt "python-4.0.0" "$VERSION"
+}
+
+# Check if Python version needs to install SQLite3
+python_sqlite3_check() {
+  VERSION="$1"
+  MIN_PYTHON_3="python-3.5.6"
+  MIN_PYTHON_2="python-2.7.15"
+
+  ( python2_check "$VERSION" && version_gte "$VERSION" "$MIN_PYTHON_2" ) \
+    || ( python3_check "$VERSION" && version_gte "$VERSION" "$MIN_PYTHON_3" )
+}

bin/warnings

@@ -1,3 +1,4 @@
+#!/usr/bin/env bash
 shopt -s extglob
 
 old-platform() {

buildpack.toml

@@ -0,0 +1,13 @@
+[buildpack]
+name = "Python"
+
+  [publish.Ignore]
+  files = [
+    "test/",
+    ".gitignore",
+    ".dockerignore",
+    ".github/",
+    "Dockerfile",
+    "Pipfile",
+    "Pipfile.lock"
+  ]

builds/README.md

@@ -1,41 +1,57 @@
 # Python Buildpack Binaries
 
-For Cedar-14 stack
-------------------
+## Building the Docker Images
 
-To get started with it, create an app on Heroku inside a clone of this repository, and set your S3 config vars:
+**After every change to your formulae, perform the following** from the root of the Git repository (not from `builds/`) to rebuild the images for each stack:
 
-    $ heroku create --buildpack https://github.com/heroku/heroku-buildpack-python#not-heroku
-    $ heroku config:set WORKSPACE_DIR=builds
-    $ heroku config:set AWS_ACCESS_KEY_ID=<your_aws_key>
-    $ heroku config:set AWS_SECRET_ACCESS_KEY=<your_aws_secret>
-    $ heroku config:set S3_BUCKET=<your_s3_bucket_name>
+    $ docker build --pull --tag heroku-python-build-cedar-14 --file $(pwd)/builds/cedar-14.Dockerfile .
+    $ docker build --pull --tag heroku-python-build-heroku-16 --file $(pwd)/builds/heroku-16.Dockerfile .
+    $ docker build --pull --tag heroku-python-build-heroku-18 --file $(pwd)/builds/heroku-18.Dockerfile .
 
+## Using the Image
 
-Then, shell into an instance and run a build by giving the name of the formula inside `builds`:
+You can e.g. `bash` into each of the images you built using their tag:
 
-    $ heroku run bash
-    Running `bash` attached to terminal... up, run.6880
-    ~ $ bob build runtimes/python-2.7.6
+    docker run --rm -ti heroku-python-build-cedar-14 bash
+    docker run --rm -ti heroku-python-build-heroku-16 bash
+    docker run --rm -ti heroku-python-build-heroku-18 bash
 
-    Fetching dependencies... found 2:
-      - libraries/sqlite
+You then have a shell where you can run `bob build`, `bob deploy`, and so forth. You can of course also invoke these programs directly with `docker run`:
 
-    Building formula runtimes/python-2.7.6:
-        === Building Python 2.7.6
-        Fetching Python v2.7.6 source...
-        Compiling...
+    docker run --rm -ti heroku-python-build-heroku-18 bob build runtimes/python-2.7.15
 
-If this works, run `bob deploy` instead of `bob build` to have the result uploaded to S3 for you.
+In order to `bob deploy`, AWS credentials must be set up, as well as name and prefix of your custom S3 bucket (unless you're deploying to the Heroku production buckets that are pre-defined in each `Dockerfile`); see next section for details.
 
-To speed things up drastically, it'll usually be a good idea to `heroku run bash --size PX` instead.
+## Configuration
 
-For Heroku-16 stack
--------------------
+File `dockerenv.default` contains a list of required env vars; most of these have default values defined in `Dockerfile`. You can copy this file to a location outside the buildpack and modify it with the values you desire and pass its location with `--env-file`, or pass the env vars to `docker run` using `--env`.
 
-1. Ensure GNU Make and Docker are installed.
-2. From the root of the buildpack repository, run: `make buildenv-heroku-16`
-3. Follow the instructions displayed!
+Out of the box, each `Dockerfile` has the correct values predefined for `S3_BUCKET`, `S3_PREFIX`, and `S3_REGION`. If you're building your own packages, you'll likely want to change `S3_BUCKET` and `S3_PREFIX` to match your info. Instead of setting `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` into that file, you may also pass them to `docker run` through the environment, or explicitly using `--env`, in order to prevent accidental commits of credentials.
 
+### Passing AWS credentials to the container
 
-Enjoy :)
+If you want to deploy packages and thus need to pass `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY`, you can either pass them explicitly, through your environment, or through an env file.
+
+#### Passing credentials explicitly
+
+    docker run --rm -ti -e AWS_ACCESS_KEY_ID=... -e AWS_SECRET_ACCESS_KEY=... heroku-python-build-heroku-18 bash
+
+#### Passing credentials through  the environment
+
+The two environment variables `AWS_ACCESS_KEY_ID`and `AWS_SECRET_ACCESS_KEY` are defined in `builds/dockerenv.default`, without values. This will cause Docker to "forward" values for these variables from the current environment, so you can pass them in:
+
+    AWS_ACCESS_KEY_ID=... AWS_SECRET_ACCESS_KEY=... docker run --rm -ti --env-file=builds/dockerenv.default heroku-python-build-heroku-18 bash
+
+or
+
+    export AWS_ACCESS_KEY_ID=...
+    export AWS_SECRET_ACCESS_KEY=...
+    docker run --rm -ti --env-file=builds/dockerenv.default heroku-python-build-heroku-18 bash
+
+#### Passing credentials through a separate env file
+
+This method is the easiest for users who want to build packages in their own S3 bucket, as they will have to adjust the `S3_BUCKET` and `S3_PREFIX` environment variable values anyway from their default values.
+
+For this method, it is important to keep the credentials file in a location outside the buildpack, so that your credentials aren't accidentally committed. Copy `builds/dockerenv.default` **to a safe location outside the buildpack directory**, and insert your values for `AWS_ACCESS_KEY_ID`and `AWS_SECRET_ACCESS_KEY`.
+
+    docker run --rm -ti --env-file=../SOMEPATHOUTSIDE/s3.env heroku-python-build-heroku-18 bash

builds/cedar-14.Dockerfile

@@ -0,0 +1,15 @@
+FROM heroku/cedar:14
+
+WORKDIR /app
+ENV WORKSPACE_DIR="/app/builds" \
+    S3_BUCKET="lang-python" \
+    S3_PREFIX="cedar-14/" \
+    DEBIAN_FRONTEND=noninteractive \
+    STACK="cedar-14"
+
+RUN apt-get update && apt-get install -y python-pip libsqlite3-dev realpath && rm -rf /var/lib/apt/lists/*
+
+COPY requirements.txt /app/
+RUN pip install -r /app/requirements.txt
+
+COPY . /app

builds/dockerenv.default

@@ -0,0 +1,5 @@
+AWS_ACCESS_KEY_ID
+AWS_SECRET_ACCESS_KEY
+S3_BUCKET
+S3_PREFIX
+S3_REGION

builds/heroku-16.Dockerfile

@@ -3,9 +3,11 @@ FROM heroku/heroku:16-build
 WORKDIR /app
 ENV WORKSPACE_DIR="/app/builds" \
     S3_BUCKET="lang-python" \
-    S3_PREFIX="heroku-16/"
+    S3_PREFIX="heroku-16/" \
+    DEBIAN_FRONTEND=noninteractive \
+    STACK="heroku-16"
 
-RUN apt-get update && apt-get install -y python-pip && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y python-pip libsqlite3-dev && rm -rf /var/lib/apt/lists/*
 
 COPY requirements.txt /app/
 RUN pip install --disable-pip-version-check --no-cache-dir -r /app/requirements.txt

builds/heroku-18.Dockerfile

@@ -0,0 +1,15 @@
+FROM heroku/heroku:18-build.v16
+
+WORKDIR /app
+ENV WORKSPACE_DIR="/app/builds" \
+    S3_BUCKET="lang-python" \
+    S3_PREFIX="heroku-18/" \
+    DEBIAN_FRONTEND=noninteractive \
+    STACK="heroku-18"
+
+RUN apt-get update && apt-get install --no-install-recommends -y python-pip-whl=9.0.1-2 python-pip=9.0.1-2 python-setuptools python-wheel libsqlite3-dev && rm -rf /var/lib/apt/lists/*
+
+COPY requirements.txt /app/
+RUN pip install --disable-pip-version-check --no-cache-dir -r /app/requirements.txt
+
+COPY . /app

builds/libraries/sqlite

@@ -3,7 +3,7 @@
 
 OUT_PREFIX=$1
 
-echo "Building SQLite..."
+echo "Building SQLite…"
 
 
 SOURCE_TARBALL='https://www.sqlite.org/sqlite-autoconf-3070900.tar.gz'

builds/libraries/vendor/gdal

@@ -8,16 +8,17 @@ export PATH="/app/.heroku/python/bin/:$PATH"
 hash -r
 
 
-echo "Building gdal..."
+echo "Building gdal…"
 
-SOURCE_TARBALL='http://download.osgeo.org/gdal/1.11.1/gdal-1.11.1.tar.gz'
+VERSION="2.2.1"
+SOURCE_TARBALL="http://download.osgeo.org/gdal/${VERSION}/gdal-${VERSION}.tar.gz"
 
 curl -L $SOURCE_TARBALL | tar zx
 
-cd gdal-1.11.1
+pushd "gdal-${VERSION}"
 ./configure --prefix=$OUT_PREFIX --enable-static=no  &&
 make
 make install
 
 # Cleanup
-cd ..
+popd

builds/libraries/vendor/geos

@@ -8,16 +8,18 @@ export PATH="/app/.heroku/python/bin/:$PATH"
 hash -r
 
 
-echo "Building geos..."
+echo "Building geos…"
 
-SOURCE_TARBALL='http://download.osgeo.org/geos/geos-3.4.3.tar.bz2'
+VERSION=3.6.2
+
+SOURCE_TARBALL="http://download.osgeo.org/geos/geos-${VERSION}.tar.bz2"
 
 curl -L $SOURCE_TARBALL | tar xj
 
-cd geos-3.4.3
+pushd "geos-${VERSION}"
 ./configure --prefix=$OUT_PREFIX --enable-static=no &&
 make
 make install
 
 # Cleanup
-cd ..
+popd

builds/libraries/vendor/libffi

@@ -13,7 +13,7 @@ export PATH="/app/.heroku/python/bin/:$PATH"
 hash -r
 
 
-echo "Building libffi..."
+echo "Building libffi…"
 
 SOURCE_TARBALL='ftp://sourceware.org/pub/libffi/libffi-3.1.tar.gz'
 

builds/libraries/vendor/libmemcache

@@ -20,7 +20,7 @@ dep_archive_name=${dep_dirname}.tar.gz
 dep_url=https://launchpad.net/libmemcached/1.0/${dep_version}/+download/${dep_archive_name}
 
 # SASL Support.
-echo "-----> Building cyrus-sasl 2.1.26..."
+echo "-----> Building cyrus-sasl 2.1.26…"
 
 curl -LO ftp://ftp.cyrusimap.org/cyrus-sasl/cyrus-sasl-2.1.26.tar.gz
 # FTP doesn't play well with piping into tar xz
@@ -33,7 +33,7 @@ make -s -j 9
 make install -s
 popd
 
-echo "-----> Building libmemcached ${dep_version}..."
+echo "-----> Building libmemcached ${dep_version}…"
 
 curl -L ${dep_url} | tar xz
 pushd ${dep_dirname}

builds/libraries/vendor/proj

@@ -8,16 +8,17 @@ export PATH="/app/.heroku/python/bin/:$PATH"
 hash -r
 
 
-echo "Building gdal..."
+echo "Building gdal…"
 
-SOURCE_TARBALL='http://download.osgeo.org/proj/proj-4.8.0.tar.gz'
+VERSION=4.9.3
+SOURCE_TARBALL="http://download.osgeo.org/proj/proj-${VERSION}.tar.gz"
 
 curl -L $SOURCE_TARBALL | tar zx
 
-cd proj-4.8.0
-./configure --prefix=$OUT_PREFIX --enable-static=no &&
+pushd "proj-${VERSION}"
+./configure --prefix=$OUT_PREFIX --enable-static=no
 make
 make install
 
 # Cleanup
-cd ..
+popd

builds/runtimes/pypy

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+# fail hard
+set -o pipefail
+# fail harder
+set -eu
+
+OUT_PREFIX=$1
+
+dep_formula=${0#$WORKSPACE_DIR/} # this is the original script, e.g. pypy-5.3.1
+dep_name=$(basename $BASH_SOURCE) # this is us
+dep_version=${dep_formula##*"/${dep_name}-"} # "subtract" our name from full version name
+dep_package=${dep_name}2-v${dep_version} # it's always "pypy2-…"
+dep_dirname=${dep_package}-linux64
+dep_archive_name=${dep_dirname}.tar.bz2
+dep_url=https://bitbucket.org/pypy/pypy/downloads/${dep_archive_name}
+
+echo "Building PyPy…"
+
+curl -L "${dep_url}" | tar jx -C "${OUT_PREFIX}" --strip-components 1 # extract to $OUT_PREFIX, drop the first directory level, which is the archive name
+
+ln "$OUT_PREFIX/bin/pypy" "$OUT_PREFIX/bin/python"

builds/runtimes/pypy-5.3.1

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.3.1-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.3.1-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python
+source $(dirname $0)/pypy

builds/runtimes/pypy-5.6.0

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.6.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.6.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python
+source $(dirname $0)/pypy

builds/runtimes/pypy-5.7.0

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 and heroku-16 stacks, not cedar.
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.7.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.7.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python
+source $(dirname $0)/pypy

builds/runtimes/pypy-5.7.1

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy2-v5.7.1-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy2-v5.7.1-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy $OUT_PREFIX/bin/python
+source $(dirname $0)/pypy

builds/runtimes/pypy-5.8.0

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+# Build Deps: libraries/sqlite
+
+source $(dirname $0)/pypy

builds/runtimes/pypy3

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+# fail hard
+set -o pipefail
+# fail harder
+set -eu
+
+OUT_PREFIX=$1
+
+dep_formula=${0#$WORKSPACE_DIR/} # this is the original script, e.g. pypy-5.3.1
+dep_name=$(basename $BASH_SOURCE) # this is us
+dep_version=${dep_formula##*"/${dep_name}-"} # "subtract" our name from full version name
+dep_package=${dep_name}${dep_version_prefix:-}-v${dep_version}${dep_version_suffix:-}
+dep_dirname=${dep_package}-linux64
+dep_archive_name=${dep_dirname}.tar.bz2
+dep_url=https://bitbucket.org/pypy/pypy/downloads/${dep_archive_name}
+
+echo "Building PyPy3…"
+
+curl -L "${dep_url}" | tar jx -C "${OUT_PREFIX}" --strip-components 1 # extract to $OUT_PREFIX, drop the first directory level, which is the archive name
+
+ln "$OUT_PREFIX/bin/pypy3" "$OUT_PREFIX/bin/python"

builds/runtimes/pypy3-2.4.0

@@ -2,13 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy3-2.4.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy3-2.4.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy3 $OUT_PREFIX/bin/python
+source $(dirname $0)/pypy3

builds/runtimes/pypy3-5.5.0

@@ -2,13 +2,7 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-# NOTICE: This formula only works for the cedar-14 stack, not cedar.
-
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy3.3-v5.5.0-alpha-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy3-v5.5.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy3 $OUT_PREFIX/bin/python
+# version pypy3-5.5.0 is really called pypy3.3-v5.5.0-alpha
+dep_version_prefix=".3"
+dep_version_suffix="-alpha"
+source $(dirname $0)/pypy3

builds/runtimes/pypy3-5.7.1

@@ -2,11 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy3-v5.7.1-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy3-v5.7.1-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy3 $OUT_PREFIX/bin/python
+source $(dirname $0)/pypy3

builds/runtimes/pypy3-5.8.0

@@ -2,11 +2,4 @@
 # Build Path: /app/.heroku/python/
 # Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
-
-echo "Building PyPy..."
-SOURCE_TARBALL='https://bitbucket.org/pypy/pypy/downloads/pypy3-v5.8.0-linux64.tar.bz2'
-curl -L $SOURCE_TARBALL | tar jx
-cp -R pypy3-v5.8.0-linux64/* $OUT_PREFIX
-
-ln $OUT_PREFIX/bin/pypy3 $OUT_PREFIX/bin/python
+source $(dirname $0)/pypy3

builds/runtimes/python-2.7.10

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.10/Python-2.7.10.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.10 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --with-ensurepip=no
-make
-make install
+source $(dirname $0)/python2

builds/runtimes/python-2.7.11

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.11/Python-2.7.11.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.11 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --with-ensurepip=no
-make
-make install
+source $(dirname $0)/python2

builds/runtimes/python-2.7.12

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.12/Python-2.7.12.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.12 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --with-ensurepip=no
-make
-make install
+source $(dirname $0)/python2

builds/runtimes/python-2.7.13

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.13/Python-2.7.13.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.13 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --enable-unicode=ucs4 --with-ensurepip=no
-make
-make install
+source $(dirname $0)/python2

builds/runtimes/python-2.7.14

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python2

builds/runtimes/python-2.7.15

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python2

builds/runtimes/python-2.7.16

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python2

builds/runtimes/python-2.7.17

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+OUT_PREFIX=$1
+BIN_DIR="$(cd "$(dirname "$0")"/../.. || exit; pwd)/bin"
+export BIN_DIR
+
+# shellcheck source=bin/utils
+source "$BIN_DIR/steps/sqlite3"
+
+sqlite3_version
+echo "Setting up SQLite3 Headers for $SQLITE3_VERSION"
+sqlite3_install "$OUT_PREFIX" "$SQLITE3_VERSION" 1
+
+echo "Building Python…"
+SOURCE_TARBALL='https://python.org/ftp/python/2.7.17/Python-2.7.17.tgz'
+curl -L $SOURCE_TARBALL | tar xz
+mv Python-2.7.17 src
+cd src
+
+./configure --prefix=$OUT_PREFIX  --enable-unicode=ucs4 --with-ensurepip=no
+make
+make install
+
+# Remove unneeded test directories, similar to the official Docker Python images:
+# https://github.com/docker-library/python
+find "${OUT_PREFIX}" \( -type d -a \( -name test -o -name tests \) \) -exec rm -rf '{}' +

builds/runtimes/python-2.7.9

@@ -1,15 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
 
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/2.7.9/Python-2.7.9.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-2.7.9 src
-cd src
-
-./configure --prefix=$OUT_PREFIX  --with-ensurepip=no
-make
-make install
+source $(dirname $0)/python2

builds/runtimes/python-3.4.10

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+OUT_PREFIX=$1
+BIN_DIR="$(cd "$(dirname "$0")"/../.. || exit; pwd)/bin"
+export BIN_DIR
+
+# shellcheck source=bin/utils
+source "$BIN_DIR/steps/sqlite3"
+
+sqlite3_version
+echo "Setting up SQLite3 Headers for $SQLITE3_VERSION"
+sqlite3_install "$OUT_PREFIX" "$SQLITE3_VERSION" 1
+
+echo "Building Python…"
+SOURCE_TARBALL='https://python.org/ftp/python/3.7.2/Python-3.7.2.tgz'
+curl -L $SOURCE_TARBALL | tar xz
+mv Python-3.7.2 src
+cd src
+
+./configure --prefix=$OUT_PREFIX --with-ensurepip=no
+make
+make install
+
+# Remove unneeded test directories, similar to the official Docker Python images:
+# https://github.com/docker-library/python
+find "${OUT_PREFIX}" \( -type d -a \( -name test -o -name tests \) \) -exec rm -rf '{}' +
+
+# Remove spare /
+LOCATION=${OUT_PREFIX%?}
+
+ln $LOCATION/bin/python3 $LOCATION/bin/python

builds/runtimes/python-3.4.9

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+OUT_PREFIX=$1
+BIN_DIR="$(cd "$(dirname "$0")"/../.. || exit; pwd)/bin"
+export BIN_DIR
+
+# shellcheck source=bin/utils
+source "$BIN_DIR/steps/sqlite3"
+
+sqlite3_version
+echo "Setting up SQLite3 Headers for $SQLITE3_VERSION"
+sqlite3_install "$OUT_PREFIX" "$SQLITE3_VERSION" 1
+
+echo "Building Python…"
+SOURCE_TARBALL='https://python.org/ftp/python/3.4.9/Python-3.4.9.tgz'
+curl -L $SOURCE_TARBALL | tar xz
+mv Python-3.4.9 src
+cd src
+
+./configure --prefix=$OUT_PREFIX --with-ensurepip=no
+make
+make install
+
+# Remove unneeded test directories, similar to the official Docker Python images:
+# https://github.com/docker-library/python
+find "${OUT_PREFIX}" \( -type d -a \( -name test -o -name tests \) \) -exec rm -rf '{}' +
+
+# Remove spare /
+LOCATION=${OUT_PREFIX%?}
+
+ln $LOCATION/bin/python3 $LOCATION/bin/python

builds/runtimes/python-3.5.0

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.1

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.2

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.5.2/Python-3.5.2.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.5.2 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-# ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.5.3

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.5.3/Python-3.5.3.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.5.3 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-# ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.5.4

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.5

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.6

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.5.7

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.0

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.6.0/Python-3.6.0.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.6.0 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.6.1

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.6.1/Python-3.6.1.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.6.1 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.6.2

@@ -1,18 +1,4 @@
 #!/usr/bin/env bash
 # Build Path: /app/.heroku/python/
-# Build Deps: libraries/sqlite
-
-OUT_PREFIX=$1
-
-echo "Building Python..."
-SOURCE_TARBALL='https://python.org/ftp/python/3.6.2/Python-3.6.2.tgz'
-curl -L $SOURCE_TARBALL | tar xz
-mv Python-3.6.2 src
-cd src
-
-./configure --prefix=$OUT_PREFIX --with-ensurepip=no
-make
-make install
-
-ln $OUT_PREFIX/bin/python3 $OUT_PREFIX/bin/python
 
+source $(dirname $0)/python3

builds/runtimes/python-3.6.3

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.4

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.5

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.6

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.7

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.8

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.6.9

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.7.0

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.7.1

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.7.2

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.7.3

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.7.4

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.7.5

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python-3.8.0

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+source $(dirname $0)/python3

builds/runtimes/python2

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+# Build Path: /app/.heroku/python/
+
+OUT_PREFIX=$1
+BIN_DIR="$(cd "$(dirname "$0")"/../.. || exit; pwd)/bin"
+export BIN_DIR
+
+# Orient ourselves and build download link
+dep_formula=${0#$WORKSPACE_DIR/} # this is the original script, e.g. pypy-5.3.1
+BASE=${dep_formula##*/} # this gives us relative path
+python_version=${BASE^} # this gives us only the filename with version number
+version_number=$(echo "$python_version" | cut -d- -f2) # this returns just X.X.X
+dep_url=https://python.org/ftp/python/${version_number}/${python_version}.tgz
+
+echo "Building ${python_version}..."
+echo "Pulling from source: ${dep_url}"
+
+curl -L "${dep_url}" | tar xz -C "${OUT_PREFIX}"
+mv "${OUT_PREFIX}/${python_version}" src
+cd src
+
+./configure --prefix=$OUT_PREFIX  --enable-unicode=ucs4 --with-ensurepip=no
+make
+make install
+
+# Remove unneeded test directories, similar to the official Docker Python images:
+# https://github.com/docker-library/python
+find "${OUT_PREFIX}" \( -type d -a \( -name test -o -name tests \) \) -exec rm -rf '{}' +
+
+# Create links to SQLITE headers so Python can call them at runtime
+mkdir -p ${OUT_PREFIX}/include ${OUT_PREFIX}/lib/x86_64-linux-gnu
+cp /usr/include/sqlite3*.h ${OUT_PREFIX}/include
+ln -fs $(realpath /usr/lib/x86_64-linux-gnu/libsqlite3.so) ${OUT_PREFIX}/lib/x86_64-linux-gnu/libsqlite3.so

builds/runtimes/python3

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+# fail hard
+set -o pipefail
+# fail harder
+set -eu
+
+OUT_PREFIX=$1
+BIN_DIR="$(cd "$(dirname "$0")"/../.. || exit; pwd)/bin"
+export BIN_DIR
+
+# Orient ourselves and build download link
+dep_formula=${0#$WORKSPACE_DIR/} # this is the original script, e.g. pypy-5.3.1
+BASE=${dep_formula##*/} # this gives us relative path
+python_version=${BASE^} # this gives us only the filename with version number
+version_number=$(echo "$python_version" | cut -d- -f2) # this returns just X.X.X
+dep_url=https://python.org/ftp/python/${version_number}/${python_version}.tgz
+
+curl -L "${dep_url}" | tar xz -C "${OUT_PREFIX}"
+mv "${OUT_PREFIX}/${python_version}" src
+cd src
+
+./configure --prefix=$OUT_PREFIX --with-ensurepip=no
+make
+make install
+
+# Remove unneeded test directories, similar to the official Docker Python images:
+# https://github.com/docker-library/python
+find "${OUT_PREFIX}" \( -type d -a \( -name test -o -name tests \) \) -exec rm -rf '{}' +
+
+# Remove spare /
+LOCATION=${OUT_PREFIX%?}
+
+# Create links to SQLITE headers so Python can call them at runtime
+mkdir -p ${OUT_PREFIX}/include ${OUT_PREFIX}/lib/x86_64-linux-gnu
+cp /usr/include/sqlite3*.h ${OUT_PREFIX}/include
+ln -fs $(realpath /usr/lib/x86_64-linux-gnu/libsqlite3.so) ${OUT_PREFIX}/lib/x86_64-linux-gnu/libsqlite3.so
+
+ln $LOCATION/bin/python3 $LOCATION/bin/python

etc/ci-setup.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+sudo apt-get -qq update
+sudo apt-get install software-properties-common
+curl --fail --retry 3 --retry-delay 1 --connect-timeout 3 --max-time 30 https://cli-assets.heroku.com/install-ubuntu.sh | sh