ci: merge images

[C4illin]

Summary by Sourcery

Enhance the Docker CI workflow to support multi-architecture builds and automated manifest list merging for both GitHub Container Registry and Docker Hub.

New Features:

• Publish per-platform image digests as artifacts for later use
• Merge and push multi-architecture manifest lists to GHCR and Docker Hub

Enhancements:

• Standardize platform identifiers to linux/amd64 and linux/arm64 in the build matrix
• Introduce a step to normalize platform names into PLATFORM_PAIR for artifact naming
• Enable OCI annotations, digest outputs, and GitHub Actions cache in the build stage
• Clean up branch and tag array syntax in the workflow configuration

CI:

• Add a new "merge" job to download digests, set up buildx, log in to registries, and push manifest lists
• Use actions/upload-artifact and download-artifact to pass digests between jobs

[sourcery-ai]

Reviewer's Guide

This PR refactors and extends the Docker publish workflow to support standardized YAML formatting, multi-architecture builds, per-arch digest export/upload, and a new merge job that consolidates image digests into universal manifests for both GHCR and Docker Hub.

Sequence Diagram: Multi-Arch Docker Image Build and Manifest Merge

sequenceDiagram
    title Sequence Diagram: Multi-Arch Docker Image Build and Manifest Merge
    actor User
    participant GA as GitHub Actions
    participant Build_amd64 as "Build Job (linux/amd64)"
    participant Build_arm64 as "Build Job (linux/arm64)"
    participant Artifacts as "GitHub Artifacts"
    participant Merge as "Merge Job"
    participant GHCR
    participant DockerHub

    User->>GA: Event (Push, Tag, Workflow Dispatch)
    GA->>Build_amd64: Start Build (amd64)
    GA->>Build_arm64: Start Build (arm64)

    par
        Build_amd64->>Build_amd64: Checkout, Setup Buildx
        Build_amd64->>GHCR: Login (if not PR)
        Build_amd64->>DockerHub: Login (if not PR)
        Build_amd64->>Build_amd64: Build image (amd64)
        Build_amd64-->>GHCR: Push amd64 image & manifest
        Build_amd64-->>DockerHub: Push amd64 image & manifest
        note right of Build_amd64: Get digest of pushed amd64 manifest
        Build_amd64->>Artifacts: Upload amd64 digest
    and
        Build_arm64->>Build_arm64: Checkout, Setup Buildx
        Build_arm64->>GHCR: Login (if not PR)
        Build_arm64->>DockerHub: Login (if not PR)
        Build_arm64->>Build_arm64: Build image (arm64)
        Build_arm64-->>GHCR: Push arm64 image & manifest
        Build_arm64-->>DockerHub: Push arm64 image & manifest
        note right of Build_arm64: Get digest of pushed arm64 manifest
        Build_arm64->>Artifacts: Upload arm64 digest
    end

    alt If not Pull Request AND Build Jobs Successful
        GA->>Merge: Start Merge Job
        Merge->>Artifacts: Download all digests
        Merge->>GHCR: Login
        Merge->>GHCR: Create & Push Manifest List (using digests)
        Merge->>DockerHub: Login
        Merge->>DockerHub: Create & Push Manifest List (using digests)
        Merge->>Merge: Inspect final images (optional)
    end

Loading

File-Level Changes

Change	Details	Files
Standardize workflow YAML formatting	Quotation style unified for branch and tag lists Removed trailing whitespace	.github/workflows/docker-publish.yml
Expand and normalize multi-arch build matrix	Prefixed matrix.platform entries with "linux/" Updated runner include entries to match new platform names	.github/workflows/docker-publish.yml
Introduce platform-specific environment preparation	Added "prepare" step to transform matrix.platform into PLATFORM_PAIR Export PLATFORM_PAIR as GitHub Actions environment variable	.github/workflows/docker-publish.yml
Configure Buildx dynamically for target platforms	Passed matrix.platform to docker/setup-buildx-action Unified platforms parameter in docker/build-push-action	.github/workflows/docker-publish.yml
Enhance build-and-push action invocation	Replaced hardcoded push logic with dynamic push flags Added annotations and outputs for image metadata	.github/workflows/docker-publish.yml
Export and upload per-architecture digests	Added steps to export image digest to file Uploaded digest files as artifacts with retention settings	.github/workflows/docker-publish.yml
Add merge job to create and push manifest lists	Downloaded per-arch digests from artifacts Extracted metadata and logged into registries Built and pushed manifest lists for GHCR and Docker Hub Inspected final image manifests	.github/workflows/docker-publish.yml

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[sourcery-ai]

Hey @C4illin - I've reviewed your changes - here's some feedback:

• Add an explicit id: to the docker/build-push-action@v6 step so you can reliably reference its digest output in subsequent steps.
• Remove or re-enable the commented-out push: line under the build step to ensure images get pushed when not in a PR workflow.
• Update the prepare‐step comment to match the actual environment variable (PLATFORM_PAIR) you’re setting (it currently refers to PLATFORMS_PAIR).

Here's what I looked at during the review

• 🟡 General issues: 1 issue found
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟢 Documentation: all looks good

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[M3dvidek]

Super. Will update when I go home and test calibre