From c982cd1240e5f2c0c244d772453d4d8a5e405b54 Mon Sep 17 00:00:00 2001
From: Kenneth Reitz <me@kennethreitz.org>
Date: Wed, 13 Feb 2019 07:02:07 -0500
Subject: [PATCH] prototype

---
 bin/compile | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 bin/detect  |  10 +++++
 2 files changed, 137 insertions(+)
 create mode 100644 bin/compile
 create mode 100644 bin/detect

diff --git a/bin/compile b/bin/compile
new file mode 100644
index 0000000..e0763b2
--- /dev/null
+++ b/bin/compile
@@ -0,0 +1,127 @@
+#!/usr/bin/env bash
+
+# Fail fast and fail hard.
+set -eo pipefail
+
+# 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=$3
+
+
+# Set the Buildpack's internet target for downloading Python distributions.
+# The user can provide BUILDPACK_VENDOR_URL to specify a custom target.
+# Note: this is designed for non-Heroku use, as it does not use the user-provided
+# environment variable mechanism (the ENV_DIR).
+VENDOR_URL="https://lang-python.s3.amazonaws.com/$STACK"
+if [[ -n ${BUILDPACK_VENDOR_URL:-} ]]; then
+    VENDOR_URL="$BUILDPACK_VENDOR_URL"
+fi
+export VENDOR_URL
+
+# Which versions of Python are we using?
+# These variables are used to specify which versions of Python to install by default,
+# as well as prompt the user to upgrade if they are using an un–supported version.
+# Note: When 3.7 lands, I recommend switching to LATEST_36 and LATEST_37.
+DEFAULT_PYTHON_VERSION="python-3.7.2"
+
+mkdir -p /app/.heroku
+mkdir -p "$CACHE_DIR"
+
+# Restore old artifacts from the cache.
+mkdir -p .heroku
+
+# The Python installation.
+cp -R "$CACHE_DIR/.heroku/python" .heroku/ &> /dev/null || true
+
+# The location of the pre-compiled python binary.
+VENDORED_PYTHON="${VENDOR_URL}/runtimes/$PYTHON_VERSION.tar.gz"
+
+puts-step "Installing $PYTHON_VERSION"
+
+set +e
+# Prepare destination directory.
+mkdir -p .heroku/python
+if ! curl "${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
+
+hash -r
+set -e
+
+if [[ -f Pipfile.lock ]]; then
+    if [[ -f .heroku/python/Pipfile.lock.sha256 ]]; then
+        if [[ $(openssl dgst -sha256 Pipfile.lock) == $(cat .heroku/python/Pipfile.lock.sha256) ]]; then
+            
+            if ! grep -q 'git' Pipfile.lock; then
+                echo "Skipping installation, as Pipfile.lock hasn't changed since last deploy." | indent
+                
+                export SKIP_PIPENV_INSTALL=1
+            fi
+        fi
+    fi
+fi
+
+
+
+if [ ! "$SKIP_PIPENV_INSTALL" ]; then
+    # Pipenv support (Generate requriements.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
+        
+        # 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 dependencies.
+        if [[ ! -f Pipfile.lock ]]; then
+            puts-step "Installing dependencies with Pipenv $PIPENV_VERSION…"
+            /app/.heroku/python/bin/pipenv install --system --skip-lock 2>&1 | indent
+        else
+            "$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 $PIPENV_VERSION…"
+            /app/.heroku/python/bin/pipenv install --system --deploy 2>&1 | indent
+        fi
+        
+        # Install the test dependencies, for CI.
+        if [ "$INSTALL_TEST" ]; then
+            puts-step "Installing test dependencies…"
+            /app/.heroku/python/bin/pipenv install --dev --system --deploy 2>&1 | cleanup | indent
+        fi
+    fi
+else
+    export SKIP_PIP_INSTALL=1
+fi
diff --git a/bin/detect b/bin/detect
new file mode 100644
index 0000000..3555c9d
--- /dev/null
+++ b/bin/detect
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+BUILD_DIR=$1
+
+# Exit early if app is clearly not Python.
+if [ ! -f "$BUILD_DIR/Pipfile" ]; then
+    exit 1
+fi
+
+echo "Python/Pipenv"