A transient remote lookup error dropped the serve_stale copy of a virtual member and forced a blocking fetch, so a short DB blip stalled every merge.
- serve the existing copy on a lookup error and refresh it in the background
- fetch directly without storing anything on a lookup error with no copy
- create copies only after a successful lookup with serve_stale on
Reviewed-on: #171
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>
TestServeStaleMemberDoesNotBlockMerge reads the fetch counter right after the merges return, but the counted fetch runs inside the background refresh goroutine, so a slow schedule sees 1 instead of 2.
- signal from the stub fetch when the background refresh starts
- wait on that signal (5s timeout) before checking the fetch count
- raise the refresh-reaches-merge deadline to 5s
Reviewed-on: #172
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>
Virtual merges expire after 60s and the next request blocks on every member. One slow member (a large github_rpm remote) makes the re-merge outlast dnf's 30s timeout.
- add `serve_stale` to remotes (model, v2 API, migration 0008, UI, TUI), default false
- serve a flagged member's last good fetch to rpm/deb/alpine merges at once
- refresh it in the background, single-flighted, detached from the request
- block on the member again once its copy is over an hour old, or the flag is off
- prune copies with their merge cache; drop refreshes for evicted entries
Reviewed-on: #167
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>
unkin-agent