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fix(gzip)!: change the default block size #529

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merged 1 commit into from Oct 20, 2023

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rchincha
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BREAKING CHANGE: the default gzip block size is changed to 256<<12, was previously 256<<10.

The layers created by ecosystem tools and stacker are different for the same tar content. Unfortunately, the OCI image spec doesn't standardize/encode this in the document. Hence, we standardize in the implementation.

We now link against our own fork: github.com/project-stacker/umoci which may change depending on the PR getting merged to upstream.

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Which issue does this PR fix:

What does this PR do / Why do we need it:

If an issue # is not available please add repro steps and logs showing the issue:

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Will this break upgrades or downgrades?

Does this PR introduce any user-facing change?:


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

pkg/overlay/pack.go Outdated Show resolved Hide resolved
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codecov bot commented Oct 19, 2023

Codecov Report

Merging #529 (d89af75) into main (565b032) will not change coverage.
Report is 1 commits behind head on main.
The diff coverage is 0.00%.

@@           Coverage Diff           @@
##             main     #529   +/-   ##
=======================================
  Coverage   13.34%   13.34%           
=======================================
  Files          40       40           
  Lines        5852     5852           
=======================================
  Hits          781      781           
  Misses       4943     4943           
  Partials      128      128           
Files Coverage Δ
pkg/overlay/pack.go 0.00% <0.00%> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

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Suggestion in commit message:

A tar layer with the same content but compressed with different gzip blocksize
will result in different sha256sums in the final OCI Image. Ecosystem tools
have one current size in use and stacker's current size differ.

Interactions between a stacker-built OCI image and ecosystem tools
which recompress lower layers results in bloated registries which will have
identical tar content but different compressed sha256 blobs.

Unfortunately, the OCI image spec doesn't standardize/encode this in the
specification document. Hence, we change to the current common block size used
in the ecosystem here in the stacker implementation.

BREAKING CHANGE: the default gzip block size is changed to 256<<12, was
previously 256<<10.

A tar layer with the same content but compressed with different gzip
blocksize will result in different sha256sums in the final OCI Image.
Ecosystem tools have one current size in use and stacker's current size
differ.

Interactions between a stacker-built OCI image and ecosystem tools which
recompress lower layers results in bloated registries which will have
identical tar content but different compressed sha256 blobs.

Unfortunately, the OCI image spec doesn't standardize/encode this in the
specification document. Hence, we change to the current common block
size used in the ecosystem here in the stacker implementation.

We now link against our own fork: github.com/project-stacker/umoci
which may change depending on the PR getting merged to upstream.

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>
@rchincha
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Suggestion in commit message:

Updated.

@rchincha rchincha merged commit 0cf2d70 into project-stacker:main Oct 20, 2023
8 of 9 checks passed
rchincha added a commit to rchincha/stacker that referenced this pull request Nov 17, 2023
BREAKING CHANGE: the default gzip block size is changed to 256<<12, was
previously 256<<10.

A tar layer with the same content but compressed with different gzip
blocksize will result in different sha256sums in the final OCI Image.
Ecosystem tools have one current size in use and stacker's current size
differ.

Interactions between a stacker-built OCI image and ecosystem tools which
recompress lower layers results in bloated registries which will have
identical tar content but different compressed sha256 blobs.

Unfortunately, the OCI image spec doesn't standardize/encode this in the
specification document. Hence, we change to the current common block
size used in the ecosystem here in the stacker implementation.

We now link against our own fork: github.com/project-stacker/umoci
which may change depending on the PR getting merged to upstream.

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>
(cherry picked from commit 0cf2d70)
Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>
rchincha added a commit to rchincha/stacker that referenced this pull request Nov 17, 2023
BREAKING CHANGE: the default gzip block size is changed to 256<<12, was
previously 256<<10.

A tar layer with the same content but compressed with different gzip
blocksize will result in different sha256sums in the final OCI Image.
Ecosystem tools have one current size in use and stacker's current size
differ.

Interactions between a stacker-built OCI image and ecosystem tools which
recompress lower layers results in bloated registries which will have
identical tar content but different compressed sha256 blobs.

Unfortunately, the OCI image spec doesn't standardize/encode this in the
specification document. Hence, we change to the current common block
size used in the ecosystem here in the stacker implementation.

We now link against our own fork: github.com/project-stacker/umoci
which may change depending on the PR getting merged to upstream.

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>
(cherry picked from commit 0cf2d70)
Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>
rchincha added a commit that referenced this pull request Nov 17, 2023
BREAKING CHANGE: the default gzip block size is changed to 256<<12, was
previously 256<<10.

A tar layer with the same content but compressed with different gzip
blocksize will result in different sha256sums in the final OCI Image.
Ecosystem tools have one current size in use and stacker's current size
differ.

Interactions between a stacker-built OCI image and ecosystem tools which
recompress lower layers results in bloated registries which will have
identical tar content but different compressed sha256 blobs.

Unfortunately, the OCI image spec doesn't standardize/encode this in the
specification document. Hence, we change to the current common block
size used in the ecosystem here in the stacker implementation.

We now link against our own fork: github.com/project-stacker/umoci
which may change depending on the PR getting merged to upstream.


(cherry picked from commit 0cf2d70)

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>
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2 participants