--commit-range ignored, needs documentation update

[consideRatio]

Since 55fe935, the --commit-range argument is no longer needed for chartpress to do a good job.

We should update the documentation to reflect this.

[yuvipanda]

Don't you still need commit range if the docker image gets pushed to an authenticated registry on deploy, but you want to use chartpress to build the image in PR without giving it the credentials to access the registry?

[consideRatio]

Hmm... yes. The chartpress logic currently is that a check is run if it is locally available, and if it isn't, it checks in the external docker repository. But, if you at this point don't have access to the repository for the check because you didn't want to provide such credentials, you should fall back to rebuilding it right?

This may already be what's happening, if the docker.errors.APIError is raised at least.

chartpress/chartpress.py

Lines 141 to 160 in 9ded86b

	def image_needs_pushing(image):
	"""Return whether an image needs pushing
	Args:
	image (str): the `repository:tag` image to be build.
	Returns:
	True: if image needs to be pushed (not on registry)
	False: if not (already present on registry)
	"""
	d = docker_client()
	try:
	d.images.get_registry_data(image)
	except docker.errors.APIError:
	# image not found on registry, needs pushing
	return True
	else:
	return False

[yuvipanda]

As an example, see https://github.com/berkeley-dsep-infra/datahub/blob/235ba9f7af14e16f8b25d85799b75737c199da4b/.circleci/config.yml#L46

This never hits the docker API at all if the images haven't changed in commit-range. If we rebuilt it all the time it will slow down PRs considerably.

[consideRatio]

@yuvipanda yes I agree and care about this optimization a lot, but since the already merged commit mentioned, or chartpress 0.3.1 i believe, --commit-range is not consumed even though it is passed.

The commit-range args are parsed, and then passed to the build images function, but then never used since the commit referenced in the original post. Instead logic to see if the image is locally or externally avaialable is used to determine the need for the image to rebuild.

And yes, if the external image registry is private and the docker client used isnt having the proper credentials, it wount be able to conclude if it is externally available. Above I reasoned that it would not be able to fetch it for use either.