feat(cli): add publish-assets command for asset publishing without deployment

[go-to-k]

cdk publish-assets

Publishes assets for the specified stack(s) without performing a deployment.

Important

cdk publish-assets is under development and therefore must be opted in via the --unstable flag: cdk publish-assets --unstable=publish-assets. --unstable indicates that the scope and API of feature might still change. Otherwise the feature is generally production ready and fully supported.

Publishes assets (such as Docker images and file assets) for the specified stack(s) to their respective destinations (ECR repositories, S3 buckets) without performing a deployment.

This is useful in CI/CD pipelines where you want to separate the asset build/publish phase from the deployment phase.

$ # Publish assets for a single stack
$ cdk publish-assets MyStack --unstable=publish-assets

$ # Publish assets for all stacks
$ cdk publish-assets --all --unstable=publish-assets

$ # Force re-publish even if assets already exist
$ cdk publish-assets MyStack --unstable=publish-assets --force

---

Currently, cdk deploy combines asset publishing and stack deployment into a single operation. This makes it difficult to structure CI/CD pipelines where assets should be built and published once, then reused across multiple deployment stages (e.g. dev → staging → production). The solution today is to use the standalone cdk-assets CLI directly, which requires an additional dependency and likely not easily discoverable.

This PR adds cdk publish-assets as a first-class CLI command, making the same functionality available without extra dependencies and with the familiar CDK CLI experience (stack selectors, --exclusively, --all, --concurrency).

On the implementation side, the inline buildAsset and publishAsset functions in the deploy path have been extracted into reusable createBuildAssetFunction and createPublishAssetFunction methods on the Toolkit class, so both deploy and publish-assets share the same asset handling logic.

Fixes #982

---

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

[codecov-commenter]

Codecov Report

❌ Patch coverage is 95.45455% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.19%. Comparing base (87b3f6c) to head (999a579).
⚠️ Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/aws-cdk/lib/cli/cli.ts	91.30%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1020      +/-   ##
==========================================
+ Coverage   88.17%   88.19%   +0.01%     
==========================================
  Files          73       73              
  Lines       10345    10386      +41     
  Branches     1403     1410       +7     
==========================================
+ Hits         9122     9160      +38     
- Misses       1196     1199       +3     
  Partials       27       27              

Flag	Coverage Δ
suite.unit	88.19% <95.45%> (+0.01%)	⬆️

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[go-to-k]

@mrgrain Applied your comments!

[hoegertn]

Thanks you very much to both of you. I really appreciate the effort that you put into this feature.

I will definitely try it out immediately after release and change my pipelines.

Aghain, thanks a lot.