(cli): Add cdk publish command for asset publishing

[hoegertn]

Describe the feature

Add a new cdk publish CLI command that uploads synthesized assets (container images, Lambda bundles, file assets, etc.) to their respective destinations without performing a deployment.

Use Case

In CI/CD pipelines, the recommended best practice is to separate the build/publish phase from the deployment phase:

Synthesize (cdk synth) - Generate CloudFormation templates and asset manifests
Publish - Upload all assets (Docker images, Lambda ZIPs, S3 files) to their destinations
Deploy - Deploy stacks sequentially across stages/environments (without re-uploading assets)

Currently, cdk deploy combines asset publishing and deployment into a single operation. This creates challenges in enterprise CI/CD pipelines:

• Immutable artifacts: Assets should be published once and reused across multiple deployments (dev → staging → production)
• Separation of concerns: Build/publish should complete before any deployment begins
• Reduced deployment time: When deploying to multiple stages, assets only need to be uploaded once
• Atomic releases: All assets are verified to be published before any deployment starts
• Pipeline structure: Most CI/CD systems (GitHub Actions, GitLab CI, CodePipeline, Jenkins) work best with distinct publish and deploy stages

The only way to achieve this workflow today is by installing and using the cdk-assets package directly:

This approach has drawbacks:

• Requires an additional dependency
• Not well documented in the main CDK documentation
• The API and usage is less discoverable than built-in CLI commands
• Users must understand the internal asset manifest structure

Proposed Solution

Add a cdk publish command to the CDK CLI.

Other Information

• This aligns with the CDK Pipelines concept where assets are published before deployment
• The underlying functionality already exists in cdk-assets - this would expose it as a first-class CLI command

If this is implemented, it would be also beneficial to have an option in the cdk deploy command to skip publishing during the deploy step.

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.x

Environment details (OS name and version, etc.)

all

[hoegertn]

@mrgrain as discussed at RIV

[netvolart]

Thanks, guys. This is so great feature.

Could it be useful to add ability to specify custom ECR and S3 for assets instead of created by cdk bootstrap ?

The use case is still the same like was in topic, but assuming we have different environments in different accounts.
I was building assets with cdk (it's su user friendly for dev team to describe this in CDK). But It requires to build and publish assets in each AWS account.
So I've changed the process in pipeline to build images just in docker without cdk, promote between accounts and pass the ECRUri to the CDK during the deployment.
If we will add ability to specify custom ECR and S3 in publish-assets feature, I will be able to build an publish with cdk, promote assets between accounts (just aws cli), and deploy with cdk in multi-account environment.