Before, this only waited for the download to complete. There was no
guarantee that the layer had been registered in the graph and was ready
use. This is especially problematic with v2 pulls, which wait for all
downloads before extracting layers.
Change Broadcaster to allow an error value to be propagated from Close
to the waiters.
Make the wait stop when the extraction is finished, rather than just the
download.
This also fixes v2 layer downloads to prefix the pool key with "layer:"
instead of "img:". "img:" is the wrong prefix, because this is what v1
uses for entire images. A v1 pull waiting for one of these operations to
finish would only wait for that particular layer, not all its
dependencies.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Without this change, there was a narrow race condition that would allow
writers to finish when there was still data left to write. This is
likely to be what was causing some integration tests to fail with
truncated pull output.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This means the writing to a WriteFlusher will flush in the same places
as it would if the broadcaster wasn't sitting in front of it.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
- Rename to Broadcaster
- Document exported types
- Change Wait function to just wait. Writing a message to the writer and
adding the writer to the observers list are now handled by separate
function calls.
- Avoid importing logrus (the condition where it was used should never
happen, anyway).
- Make writes non-blocking
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
