Pulp

I agree with the problem this story identifies. We need a way for plugin to add lazy support while still using the ArtifactDownloader and ArtifactSaver stages in the pipeline.

There is a related problem that we need to consider at the same times as this one because I believe one solution will resolve all of these issues. Plugins that discover content to download from content downloaded by the pipeline would need additional ArtifactDownloader and ArtifactSaver stages later in the pipeline. Adding more stages later fixes that issue, but since the pipeline size has to be fixed and the number of "discoveries" does not this solution can't address all plugin needs. For example the Maven sync will have this issue.

I'm writing ^ issue up as a separate ticket now and after that I can show how that solution will also resolve this problem as well.

Option 1 seems simplest only let's name it something like DeclarativeArtifact.always_download instead. This way the attribute describes the desired behavior instead of describing the artifact which has the side effect of the desired behavior.

Just to be explicit here: Please ensure, that this is handled per Artifact. In gem, a content unit consists of two artifacts: One containing the actual gem (subject to lazy) and one containing Metadata (which in a future version might be desirable to be available immediately for dependency resolution).

BTW: Option 1 +1

If you decide for Option 1, i have a solution ready:
https://github.com/ATIX-AG/pulpcore-plugin/tree/non_lazy_artifacts

The solution agreed upon now is:¶

The DeclarativeArtifact gets a new flag called 'deferred_download' defaulting to False to specify, that the artifact stages stop processing it (making it lazy).
At the same time the 'download_artifacts' flag of DeclarativeVersion is removed.
So the plugin must either use the deferred_download flag, or tailor its own Pipeline.

bmbouter Adding the closes tag brings travis to fail with:

Error: issue #4209 has invalid status of MODIFIED. Status must be one of NEW, ASSIGNED, POST.

Removed it again.