perf(docker): install dependencies before copying source

[vilenarios]

A one-line source edit currently costs a full dependency reinstall — twice.

COPY . . sits above yarn install, so any source change invalidates that layer and everything below it. The build then re-resolves the whole tree for the compile, and again for the production prune that runs after the source copy.

Measured

Same machine, both with warm caches, identical one-line source edit:

	source-only rebuild
current	3m37s
this PR	14.5s

Most of the saving comes from moving the production install into its own stage. It depends only on the manifests, so editing source no longer re-resolves it — previously it ran as rm -rf node_modules && yarn install --production below the source copy and was rebuilt every time.

Output is unchanged

Built from identical source, both Dockerfiles produce:

• compiled dist: 721e6960bb4659a7, 469 files — byte-identical
• runtime node_modules: 04d87018b84258a5, 1010 packages — identical

No new requirements

Deliberately avoids BuildKit-only features. A yarn cache mount would also speed up genuine dependency changes, but the Dockerfile currently builds under the legacy builder and --mount=type=cache would make BuildKit a hard requirement for anyone building locally. Verified this still builds with DOCKER_BUILDKIT=0. CI is unaffected either way — it uses docker/setup-buildx-action.

One trap worth knowing

.yarnrc has to be copied alongside the manifests. It carries ignore-engines true, which some transitive dependencies need to install at all (@permaweb/aoconnect declares "engines": {"yarn": "please-use-npm"}). It was previously swept in by COPY . .; copying the manifests without it fails the install outright. That cost me one build to discover.

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Team

Run ID: 6f7377af-70ef-41c5-ab97-d2de28193ad2

📥 Commits

Reviewing files that changed from the base of the PR and between 2bedbb1 and b429463.

📒 Files selected for processing (1)

• Dockerfile

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📝 Walkthrough

Walkthrough

The Dockerfile now separates cached dependency installation, production dependency installation, application compilation, and runtime packaging into distinct stages.

Changes

Docker build pipeline

Layer / File(s)	Summary
Dependency and build stages Dockerfile	The Dockerfile adds base, deps, proddeps, and builder stages. Manifest files and .yarnrc support dependency caching. Source is copied only into the builder stage.
Runtime dependency handoff Dockerfile	The runtime image copies production-only node_modules from proddeps.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to b4294

This change reorganizes Docker dependency and build stages to improve caching while retaining the production runtime dependency handoff. No concrete merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description clearly explains the Dockerfile caching changes, measured rebuild-time improvement, unchanged outputs, and legacy-builder compatibility.
Title check	✅ Passed	The title clearly and concisely describes the main change: installing dependencies before copying source to improve Docker layer caching.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch perf/dockerfile-layer-caching

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.69%. Comparing base (428656b) to head (b429463).
⚠️ Report is 7 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #884      +/-   ##
===========================================
- Coverage    80.70%   80.69%   -0.02%     
===========================================
  Files          143      143              
  Lines        57785    57785              
  Branches      4496     4495       -1     
===========================================
- Hits         46634    46627       -7     
- Misses       11096    11103       +7     
  Partials        55       55              

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