Return error on canceled download

[llugin]

What

Return error on canceled download context

Why

in such way we are always notified that context was cancelled when calling csaf_downloader through error channel, rather than silently stopping the download process.

References

VTI-705

[github-actions]

Conventional Commits Report

😢 No conventional commits found.

👉 Learn more about the conventional commits usage at Greenbone.

[github-actions]

Modver result

This report was generated by Modver,
a Go package and command that helps you obey semantic versioning rules in your Go module.

This PR does not require a change in your module’s version number.
(You might still consider bumping the patchlevel anyway.)

[mgoetzegb]

There is a second ctx.Done() in downloadFiles where we read in the links to the CSAF documents:

csaf_distribution/cmd/csaf_downloader/downloader.go

Lines 298 to 305 in a830852

	allFiles:
	for _, file := range files {
	select {
	case advisoryCh <- file:
	case <-ctx.Done():
	break allFiles
	}
	}

I think it is the safest to also send the context error to the error channel as well.

In the end we can end up with many of those cancel errors in the error ultimately returned (one per worker + one in place mentioned above). But I think that is acceptable and better than possibly missing error feedback in edge cases.

missed something