Codecov Report

Attention: Patch coverage is 91.48936% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 82.04%. Comparing base (f1d319f) to head (fe953b1).

@@            Coverage Diff             @@
##             main    #1288      +/-   ##
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+ Coverage   81.94%   82.04%   +0.09%     
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  Files          83       83              
  Lines        4005     4016      +11     
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+ Hits         3282     3295      +13     
+ Misses        500      498       -2     
  Partials      223      223              

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Need to confirm which output should be covered in this PR.

The proposed change in this PR doesn't cover all output of ORAS. E.g. the output of oras push/attach --format xxx which is designed to be used for automation. (There are also undergoing efforts for other commands, see #638) We have a draft doc https://hackmd.io/@shizh/HyFZkEcca to categorize all types of output in ORAS.

@TerryHowe Looks like you are trying to do automation and the target output to be changed is metadata and raw output?

Thanks @TerryHowe . This is a big PR. From users' perspective, I am curious on what's the impact to ORAS CLI output. There is not an issue associated with this PR to describe the problem or enhancement.

This change has no effect on the format of the output and from my understanding no effect on CLI output. The change is really just for go scripting.

• This change uses Fprintln instead of Println so we can pass a writer.
• For the CLI cmd.OutOrStdout() will always return os.Stdout so no change in behavior

The goal is to allow oras go scripting to be able to capture output from commands without messing with stdout

The goal is to allow oras go scripting to be able to capture output from commands without messing with stdout

The output of --format won't go into STDOUT, e.g. localhost:5000/test@sha256:16ce5d4fb98496ec805e6b2401213598e710dbd936fb58cb7a325d2582924694 cannot captured by the go script.

> oras version
Version:        1.2.0-beta.1
Go version:     go1.21.6
Git commit:     9ffdb3eec60b969d842af1a9e699202e0827fa01
Git tree state: clean
> oras push localhost:5000/test:format --format {{.Ref}}
✓ Uploaded  application/vnd.oci.empty.v1+json                                                      2/2  B 100.00%   37ms
  └─ sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a
✓ Uploaded  application/vnd.oci.image.manifest.v1+json                                         535/535  B 100.00%     0s
  └─ sha256:16ce5d4fb98496ec805e6b2401213598e710dbd936fb58cb7a325d2582924694
localhost:5000/test@sha256:16ce5d4fb98496ec805e6b2401213598e710dbd936fb58cb7a325d2582924694

The output of --format won't go into STDOUT, e.g. localhost:5000/test@sha256:16ce5d4fb98496ec805e6b2401213598e710dbd936fb58cb7a325d2582924694 cannot captured by the go script.

I'd sooner handle format as a follow up.