Heroku Buildpack: Python

This is a fork of https://github.com/heroku/heroku-buildpack-python/ maintained by Plotly, and includes the following changes:

• Better support for airgap (fully offline) builds
• Improved debugging on build / deployment
• Links to DDS docs instead of to Heroku

Changelog

Please update the changelog with all updates made to our fork of the upstream buildpack. This helps maintain a list of behaviour that we are looking to preserve should the need to resolve any conflicts with upstream arises.

Tests

The buildpack tests use Docker to simulate Heroku's stack images.

To run the test suite against the default stack:

make test

Or to test against a particular stack:

make test STACK=heroku-16

To run only a subset of the tests:

make test TEST_CMD=tests/versions

The tests are run via the vendored shunit2 test framework.

Releasing

To create a release:

• Create a tag, of the form 3.1.0b1, where 3.1.0 is the On-Prem release we're currently working on and b1 is a build ID that's incremented for each build.

  git tag 3.1.0b1
  git push --tags

• Update plotly/herokuish to use the new version, create a new Herokuish release, and test with DDS.
• If needed, fix things on your branch and iterate by creating a new tag and a new Herokuish release.
• Create a PR against the appropriate branch (maintenance releases should be made against the release branch), get it approved, and merge.

Upstream Rebase

After each major release of Dash Enterprise, our buildpack fork should be rebased onto heroku/heroku-buildpack-python as needed. This should happen as soon as possible after a major release to allow for enough time to test and resolve any issues before the start of another freeze cycle. These rebases could potentially introduce a substantial amount of changes, which are likely too risky to introduce during a feature freeze.

Steps for rebase:

# add a fresh heroku remote
git remote rm heroku || true
git remote add heroku https://github.com/heroku/heroku-buildpack-python

# fetch heroku changes
git fetch heroku
git checkout origin/master
git branch -D rebase-on-upstream || true
git checkout -b rebase-on-upstream

# rebase our commits onto `heroku/heroku-buildpack-python`
# resolve any conflicts as necessary
# update vendored get-pip.py as necessary
git rebase heroku/master
git push origin rebase-on-upstream

Once the rebase is complete, simply run through the release process as detailed above.

Dependency sync between the buildpack and dds-vendor

Our fork of the buildpack relies on dds-vendor for installing python's basic dependencies such as pip, wheel and setuptools so, the person syncing the buildpack should ensure that new versions of those dependencies also get updated on the dds-vendor's Dockerfile.