Extend the blob info cache to also cache the name of the type of
compression used on a blob that we've seen, or specific values that
indicate that we know the blob was not compressed, or that we don't
know whether or not it was compressed.
New methods for adding known blob-compression pairs and reading
candidate locations including compression information are part of a new
internal BlobInfoCache2 interface which the library's BlobInfoCache
implementors also implement.
When we copy a blob, try to record the state of compression for the
source blob, and if we applied any changes, the blob we produced.
Make sure that when TryReusingBlob successfully uses a blob from the
blob info cache, that it provides compression information in the
BlobInfo that it returns, so that manifests can be updated to describe
layers using the correct MIME types.
When attempting to write a manifest, if a manifest can't be written
because layers were compressed using an algorithm which can't be
expressed using that manifest type, continue on to trying other manifest
formats.
Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>
... so that major-version-aware Go module import
(as opposed to vX.Y.Z+incompatible, which does not allow different
packages to use different versions) works right.
Also requires adding some more GO111MODULE=on options to Makefile.
Signed-off-by: Miloslav Trmač <mitr@redhat.com>
This allows consumers who don't need the defaulting logic to pick
their desired implementation without pulling in unrelated
dependencies. For example, it allows you to consume the memory or
NoCache implementations without pulling in github.com/boltdb.
I'd initially included blobinfocache wrappers to preserve backwards
compatibility with the old API while consumers updated to the new
APIs, but Miloslav said we don't have any backwards-compatibility
commitments at the moment [1].
Having single-implementation subpackages also allows for more generic
names (e.g. NewMemoryCache is now just New), because memory.New is
clear enough while memory.NewMemoryCache stutters.
[1]: https://github.com/containers/image/pull/602#issuecomment-471570789
Signed-off-by: W. Trevor King <wking@tremily.us>
Miloslav Trmač