fix(ci): disable Docker layer cache for engine image builds

[slin1237]

Description

Engine docker builds were serving stale pip install layers from Docker cache, causing images to contain old smg-grpc-proto/servicer versions even after new releases.

Changes

• .github/workflows/_build-engine-image.yml: Add no-cache: true to the docker build step

Test Plan

• After merge, trigger vLLM docker build and verify pip freeze shows latest packages

Checklist

• Workflow updated
• (Optional) Please join us on Slack #sig-smg to discuss, review, and merge PRs

Summary by CodeRabbit

Release Notes

No end-user-visible changes in this release. This update modifies internal build infrastructure only.

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[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: dc6b1575-6523-407a-b055-0ae9e3bf278a

📥 Commits

Reviewing files that changed from the base of the PR and between 2dd1f85 and 001ef61.

📒 Files selected for processing (1)

• .github/workflows/_build-engine-image.yml

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📝 Walkthrough

Walkthrough

The Docker engine image build workflow now explicitly disables layer caching by setting no-cache: true on the docker/build-push-action@v7 step. This forces the build process to bypass Docker's cached layers, ensuring a fresh build without leveraging previously cached intermediate results.

Changes

Cohort / File(s)	Summary
Docker Build Configuration .github/workflows/_build-engine-image.yml	Added no-cache: true to the docker/build-push-action step to disable Docker layer caching during image builds.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Possibly related PRs

• fix(docker): remove GHA docker cache from engine image builds #666: Modifies the same GitHub Actions workflow step for building the engine image and changes Docker Buildx caching inputs (sets no-cache vs. removes GHA cache directives).
• ci: bump default engine vllm(0.18.0) and trt(1.3.0rc8) versions #845: Changes default base_image_ref inputs passed into the same reusable _build-engine-image.yml workflow, affecting the Docker engine build pipeline.
• fix(ci): fix Docker build UID conflict and split build vs push triggers #865: Modifies GitHub Actions workflows using docker/build-push-action with changes to push logic and other build inputs.

Suggested labels

ci, docker

Suggested reviewers

• CatherineSue
• key4ng
• XinyueZhang369

Poem

🐰 A rabbit hops through the cache so deep,
"No layers sleep!" the build will leap,
Fresh and clean, no shortcuts take,
Every image baked from scratch we make! 🏗️

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/engine-docker-no-cache

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