ContainerCollection.run sets tag to "latest" if not set.

[dan-hipschman]

This fixes issue #2545.

The issue is when you call client.containers.run("some-image") and some-image:latest doesn't exist locally. run will call ImageCollection.pull without passing a tag:

docker-py/docker/models/containers.py

Lines 808 to 814 in 2b1c7eb

	try:
	container = self.create(image=image, command=command,
	detach=detach, **kwargs)
	except ImageNotFound:
	self.client.images.pull(image, platform=platform)
	container = self.create(image=image, command=command,
	detach=detach, **kwargs)

Since the tag doesn't exist, pull will pull all tags from the repository:

docker-py/docker/models/images.py

Lines 398 to 403 in 2b1c7eb

	def pull(self, repository, tag=None, **kwargs):
	"""
	Pull an image of the given name and return it. Similar to the
	``docker pull`` command.
	If no tag is specified, all tags from that repository will be
	pulled.

This behavior of run seems unintuitive since it will only run the latest image and the rest are not needed.

This patch only modifies run. I felt like it might be preferable for pull to mimic docker pull, and only pull all tags if the user explicitly asks for that with a keyword arg like all=True. However, the current behavior of pull is documented, so that would be a major breaking change.

I also considered whether ContainerCollection.create should append the latest tag if there was none, but its current behavior is also documented. Hence, only updating run seems like the safest approach.

[aiordache]

Thank you for this PR but I think a better way to fix this is in #2671 as this issue is a side effect of missing a default for tag in the pull method.
If you don't mind I will close this in favor of what I proposed.

[dan-hipschman]

Thank you for this PR but I think a better way to fix this is in #2671 as this issue is a side effect of missing a default for tag in the pull method.
If you don't mind I will close this in favor of what I proposed.

I prefer your approach of making the default of pull() to pull only the latest tag. The only reason I didn't do that is that the "pull all" behavior is documented, and so I thought it might break some existing code.