Properly use Zimfarm offliner definition version

[benoit74]

This is a follow-up to openzim/zimfarm#1266

This PR introduced the notion of offliner definition to correctly model that scraper flags are changing over scraper releases.

We introduced it in a non-breaking way so we have "time" to adapt, but we need to move forward to clean things afterwards.

We need to adapt wp1 to:

• store somewhere which zimit offliner definition version is currently in use
• properly set this version to use when creating a schedule
• properly retrieve the definition of current version to display flags

@elfkuzco I feel like you can propose a PR here, and @audiodude and myself will review. Is it ok for you?

[elfkuzco]

Yes

[benoit74]

This was intended for wp1 ... my bad

[elfkuzco]

In openzim/zimfarm#1422, the backend determines the "latest" version to use. Is there any need for wp1 to set the version again?

[benoit74]

I think this is not such a good idea. It will work "in general", but might fail in some occasion.

WP1 has the ability to define which Docker image tag (mwoffliner version) to use, see

wp1/wp1/zimfarm.py

Lines 209 to 214 in 36c92a5

	image = CREDENTIALS[ENV].get('ZIMFARM', {}).get('image')
	if image is None:
	image = 'ghcr.io/openzim/mwoffliner:latest'
	logger.warning(
	'No ZIMFARM["image"] found in credentials, using latest (%s)', image)
	image_name, image_tag = image.split(':')

It should be able to define the offliner definition version as well.

Should WP1 decide to use a "non-latest" mwoffliner version (it does anytime after release event for few hours before its configuration gets updated), then it should use "non-latest" offliner definition version.

And it should also be able to use a custom version if needed for whatever reason.

We should probably have same behavior than in zimit-frontend:

• introduce a new configuration in credentials.py to specify offliner definition version to use
• if this configuration is not set, fallback to assume we can use the tag of Docker image as offliner definition version (because this is in general correct)

[benoit74]

Fixed by #1027