When building a manifest during a push operation, all layers must have
an associated descriptor. If a layer is missing a descriptor, that leads
to a panic.
A break inside a switch in layerAlreadyExists meant to break from the
loop surrounding the switch, but instead breaks from the switch. This
causes the loop to continue, and can overwrite the descriptor with an
empty one, leading to the panic.
Also, fix layerAlreadyExists not to abort the push when a speculative
stat on a candidate layer digest fails with an error. This could happen
in situations like a potential cross-repository mount where the user
does not have permission to access the source repository.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
Classify blobs into three categories based on size.
Use a very limited number of mount attempts and no existence check for
small blobs. Use more attempts for bigger blobs.
Also remember blob associations during layer existence check.
Blob digests are now checked in the target repository from newest to
latest. If the blob exists and the metadata entry does not, it will be
created. If the blob is not found, the metadata entry will be removed.
Signed-off-by: Michal Minář <miminar@redhat.com>
to avoid unnecessary blob re-uploads.
Cross repository mount from particular repo will most probably fail if
the user pushing to the registry is not the same as the one who pulled
or pushed to the source repo.
This PR attempts first to cross-repo mount from the source repositories
associated with the pusher's auth config. Then it falls back to other
repositories sorted from the most similar to the target repo to the
least.
It also prevents metadata deletion in cases where cross-repo mount fails
and the auth config hashes differ.
Signed-off-by: Michal Minář <miminar@redhat.com>
Currently this always uses the schema1 manifest builder. Later, it will
be changed to attempt schema2 first, and fall back when necessary.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This commit adds a transfer manager which deduplicates and schedules
transfers, and also an upload manager and download manager that build on
top of the transfer manager to provide high-level interfaces for uploads
and downloads. The push and pull code is modified to use these building
blocks.
Some benefits of the changes:
- Simplification of push/pull code
- Pushes can upload layers concurrently
- Failed downloads and uploads are retried after backoff delays
- Cancellation is supported, but individual transfers will only be
cancelled if all pushes or pulls using them are cancelled.
- The distribution code is decoupled from Docker Engine packages and API
conventions (i.e. streamformatter), which will make it easier to split
out.
This commit also includes unit tests for the new distribution/xfer
package. The tests cover 87.8% of the statements in the package.
Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
