heroku-buildpack-python/bin/compile

#!/usr/bin/env bash
# bin/compile <build-dir> <cache-dir>

set -e

BIN_DIR=$(dirname $0)
BUILD_DIR=$1
CACHE_DIR=$2

NAME=$($BIN_DIR/detect $BUILD_DIR)
PIP_DOWNLOAD_CACHE=${PIP_DOWNLOAD_CACHE:-$CACHE_DIR/pip_downloads}
VIRTUALENV_DIRS="bin include lib"

function sed() {
  # prefer GNU sed over BSD sed on OS X
  $(which gsed || which sed) "$@"
}

cd $BUILD_DIR

# copy artifacts out of cache if exists
mkdir -p $CACHE_DIR
for dir in $VIRTUALENV_DIRS; do
  cp -R $CACHE_DIR/$dir . &> /dev/null || true
done

echo "-----> Preparing virtualenv"
virtualenv --no-site-packages . | sed -u 's/^/       /'
[ "${PIPESTATUS[*]}" == "0 0" ]

echo "-----> Byte-compiling code"
find . -name "*.py" | xargs bin/python -m py_compile
[ "${PIPESTATUS[*]}" == "0 0" ]

# if Django, inject psycopg and append settings
if [ "$NAME" = "Django" ]; then
  grep -q ^psycopg2 requirements.txt || (
    echo "-----> Injecting psycopg2 into requirements for PostgreSQL support"
    echo "psycopg2==2.3.1" >> requirements.txt
  )

  SETTINGS_FILE=$(ls **/settings.py | head -1)
  echo "-----> Appending code to $SETTINGS_FILE to read from DATABASE_URL"
  
  cat >>$SETTINGS_FILE <<EOF

import os, urlparse
if os.environ.has_key('DATABASE_URL'):
    urlparse.uses_netloc.append('postgres')
    url = urlparse.urlparse(os.environ['DATABASE_URL'])
    DATABASES['default'] = {
        'ENGINE':   'django.db.backends.postgresql_psycopg2',
        'NAME':     url.path[1:],
        'USER':     url.username,
        'PASSWORD': url.password,
        'HOST':     url.hostname,
        'PORT':     url.port,
    }
EOF
fi

echo "-----> Installing dependencies with pip"
PIP_DOWNLOAD_CACHE=$PIP_DOWNLOAD_CACHE bin/pip install -r requirements.txt | sed -u 's/^/       /'
[ "${PIPESTATUS[*]}" == "0 0" ]

# store new artifacts in cache
for dir in $VIRTUALENV_DIRS; do
  rm -rf $CACHE_DIR/$dir
  cp -R $dir $CACHE_DIR/
done