fix(digests): do not mandate sha256 as the only algorithm used for hashing blobs

[andaaron]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Attention: Patch coverage is 86.15385% with 18 lines in your changes missing coverage. Please review.

Project coverage is 92.72%. Comparing base (714d8c4) to head (5e49ab1).

Files	Patch %	Lines
pkg/storage/imagestore/imagestore.go	86.95%	4 Missing and 2 partials ⚠️
pkg/storage/gc/gc.go	20.00%	4 Missing ⚠️
pkg/test/image-utils/multiarch.go	77.77%	2 Missing and 2 partials ⚠️
pkg/storage/common/common.go	90.47%	2 Missing ⚠️
pkg/test/image-utils/images.go	92.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2075      +/-   ##
==========================================
+ Coverage   92.71%   92.72%   +0.01%     
==========================================
  Files         169      169              
  Lines       22415    22467      +52     
==========================================
+ Hits        20781    20832      +51     
+ Misses       1019     1018       -1     
- Partials      615      617       +2     

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[andaaron]

See also opencontainers/distribution-spec#494

[eusebiu-constantin-petu-dbk]

lgtm

[ktarplee]

• @andaaron What else is needed on this PR? What you have looks good however I did not see the REST API changes. I expected there to be some changes necessary there.

[andaaron]

• @andaaron What else is needed on this PR? What you have looks good however I did not see the REST API changes. I expected there to be some changes necessary there.

We need the spec for specifying a non-canonical digest algorithm for the manifest in case of pushing by tag.
Once we have the spec we can implement that.

Otherwise this PR should be good for the blobs use case. But I don't know if there's any case in which the blobs use non-canonical digest algorithms while the manifest uses the canonical (sha256) digest algorithm.

[andaaron]

@rchincha I propose we merge this as is, and the API changes in a separate PR after opencontainers/distribution-spec#543 is agreed upon.

If opencontainers/distribution-spec#543 stays the same the default behavior (the case in which the digest is not specified as a query parameter) does not change, so the code in this PR would stay the same.

[rchincha]

Summarizing 6 Failures:
[FAIL] OCI Distribution Conformance Tests Pull Pull manifests [It] HEAD request to sha512 manifest (digest) should yield 200 response /data/hdd/rchincha/go/src/github.com/opencontainers/distribution-spec/conformance/01_pull_test.go:236 [FAIL] OCI Distribution Conformance Tests Pull Pull manifests [It] HEAD request to sha512 manifest (tag) should yield 200 response
/data/hdd/rchincha/go/src/github.com/opencontainers/distribution-spec/conformance/01_pull_test.go:264 [FAIL] OCI Distribution Conformance Tests Pull Pull manifests [It] GET request to sha512 manifest (digest) should yield 200 response /data/hdd/rchincha/go/src/github.com/opencontainers/distribution-spec/conformance/01_pull_test.go:301 [FAIL] OCI Distribution Conformance Tests Pull Teardown [It] Delete sha512 manifest created in setup /data/hdd/rchincha/go/src/github.com/opencontainers/distribution-spec/conformance/01_pull_test.go:383 [FAIL] OCI Distribution Conformance Tests Push Manifest Upload [It] GET request to sha512 manifest URL (digest) should yield 200 response /data/hdd/rchincha/go/src/github.com/opencontainers/distribution-spec/conformance/02_push_test.go:452 [FAIL] OCI Distribution Conformance Tests Push Teardown [It] Delete manifest created in tests /data/hdd/rchincha/go/src/github.com/opencontainers/distribution-spec/conformance/02_push_test.go:474

https://github.com/sudo-bmitch/distribution-spec/tree/pr-digest-on-tag-push
^ building against this

[rchincha]

lgtm