Pants environments example

Repo to showcase our needs for the Pants environments feature.

Goals

The main goal is to use the pants environments feature to build our pexes and run tests inside custom environments.

Features and bugfixes we need

• Set which envs should be passed from the host inside environments. Issue: pantsbuild/pants#18577.
• Use Dockerfiles as environments and the abiltiy to specify a stage. Issue: pantsbuild/pants#17714
• Cleanup containers after using them as environments. Issue: pantsbuild/pants#18307 pantsbuild/pants#20153.
• Make sure the docker image isn't built or pulled if the test is cached. Issue: pantsbuild/pants#17958.
• Allow the use of macros inside __defaults__ in BUILD files with Pants environments set. Issue: pantsbuild/pants#22376. Example: Moving the __default__ block from myapp/tests/BUILD to myapp/BUILD results in this error:

  InvalidFieldTypeException: The 'extra_env_vars' field in target
  myapp#__defaults__ must be an iterable of strings (e.g. a list of strings),
  but was `default_env_vars()` with type `<unrecognized symbol>`.
  

Setup

• You can use the devcontainer configured in .devcontainer/devcontainer.json or take care of the required dependencies like pants and exporting the env in .env manually.
• The images used as environments have to be built beforehand, since it's not possible to set Dockerfiles as environments yet. Run the script: scripts/build_environment_images.sh

Tests

• env_test.py: Checks if the env inside .env exists in your local environment. This one should always pass.
• env_inside_environment_test.py: Checks if the env exists inside the pants environment. This should pass once the feature is implemented.
• Build and check the final images with: scripts/check_final_images.sh.

Additional Information

• Most targets are categorized by the Gdal lib version used inside the image or environment. This is for testing if the pex was built inside the correct environment.