Optimize Docker Build on PR: add caching and build amd64 only

[aantn]

Before: 15m builds

After: 3m builds

[github-actions]

✅ Docker image ready for 134935b (built in 3m 35s)

• us-central1-docker.pkg.dev/robusta-development/temporary-builds/holmes:134935b

⚠️ Warning: does not support ARM (ARM images are built on release only - not on every PR)

Use this tag to pull the image for testing.

📋 Copy commands

⚠️ Temporary images are deleted after 30 days. Copy to a permanent registry before using them:

gcloud auth configure-docker us-central1-docker.pkg.dev
docker pull us-central1-docker.pkg.dev/robusta-development/temporary-builds/holmes:134935b
docker tag us-central1-docker.pkg.dev/robusta-development/temporary-builds/holmes:134935b me-west1-docker.pkg.dev/robusta-development/development/holmes-dev:134935b
docker push me-west1-docker.pkg.dev/robusta-development/development/holmes-dev:134935b

Patch Helm values in one line (choose the chart you use):

HolmesGPT chart:

helm upgrade --install holmesgpt ./helm/holmes \
  --set registry=me-west1-docker.pkg.dev/robusta-development/development \
  --set image=holmes-dev:134935b

Robusta wrapper chart:

helm upgrade --install robusta robusta/robusta \
  --reuse-values \
  --set holmes.registry=me-west1-docker.pkg.dev/robusta-development/development \
  --set holmes.image=holmes-dev:134935b

[coderabbitai]

Walkthrough

Modifies the GitHub Actions Docker workflow to restrict PR builds to x64-only architecture (removing ARM64 support), replaces build-args with GitHub Actions cache management (cache-from/cache-to), and adds messaging indicating x64-only scope with warnings that ARM images are unavailable in PR builds.

Changes

Cohort / File(s)	Summary
Docker workflow configuration .github/workflows/docker-dev-images.yaml	Restricts PR builds to linux/amd64 only (removes linux/arm64); switches cache strategy from build-args to cache-from/cache-to with type=gha, mode=max; adds "(x64 only)" labels and ARM-support warnings to PR comments; adds clarification comment on x64-only scope for speed.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• fix docker image notifications #1245: Overlaps on PR comment composition and messaging flow in the same docker-dev-images.yaml workflow.
• Build docker images on every commit #964: Related Docker workflow changes for multi-arch image builds across repository workflows.
• Skip building images on PRs from external users (forks) #1249: Directly overlaps on PR build platform handling and fork-vs-non-fork build logic in the same workflow file.

Suggested reviewers

• arikalon1
• moshemorad

Pre-merge checks

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and accurately describes the main changes: optimizing Docker builds by adding caching and restricting builds to amd64 only on PRs.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between c35e334 and 5b85fbf.

📒 Files selected for processing (1)

• .github/workflows/docker-dev-images.yaml

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (5)

• GitHub Check: build
• GitHub Check: build (3.10)
• GitHub Check: build (3.11)
• GitHub Check: llm_evals
• GitHub Check: build (3.12)

🔇 Additional comments (4)

.github/workflows/docker-dev-images.yaml (4)

118-118: LGTM!

Clear messaging to inform users about the x64-only build scope in PR builds.

---

175-186: LGTM!

The x64-only platform restriction and GHA caching are appropriate optimizations for PR builds. Non-fork PRs have the necessary permissions to both read and write to the GitHub Actions cache.

---

191-191: LGTM!

Consistent messaging in the build logs.

---

220-258: LGTM!

The ARM warning is prominently placed and clearly explains the limitation. Good user experience to inform developers upfront before they attempt to use the image on ARM infrastructure.

[github-actions]

Results of HolmesGPT evals

• ask_holmes: 7/7 test cases were successful, 0 regressions

Test suite	Test case	Status
ask	09_crashpod	✅
ask	101_loki_historical_logs_pod_deleted	✅
ask	12_job_crashing	✅
ask	162_get_runbooks	✅
ask	176_network_policy_blocking_traffic_no_runbooks	✅
ask	43_current_datetime_from_prompt	✅
ask	61_exact_match_counting	✅

Legend

• ✅ the test was successful
• :minus: the test was skipped
• ⚠️ the test failed but is known to be flaky or known to fail
• 🚧 the test had a setup failure (not a code regression)
• 🔧 the test failed due to mock data issues (not a code regression)
• 🚫 the test was throttled by API rate limits/overload
• ❌ the test failed and should be fixed before merging the PR