Fdops 5471 - Docker Image Dependency Pre-Caching

[kbrener-eis]

Docker Image Dependency Pre-Caching

Summary

Reworked DockerfileCypress and DockerfileCypressAmd so that project dependencies (yarn packages + the Cypress binary) are downloaded once at image build time and baked into the image, instead of being downloaded on every Jenkins job run.

What was changed

DockerfileCypress and DockerfileCypressAmd

• Added two persistent cache paths via env vars:
  • YARN_CACHE_FOLDER=/opt/yarn-cache
  • CYPRESS_CACHE_FOLDER=/opt/cypress-cache
• COPY package.json yarn.lock ./ before install so the layer cache is invalidated only when deps actually change.
• RUN yarn install --frozen-lockfile populates the yarn cache with every tarball the project needs and triggers Cypress's postinstall.
• RUN npx cypress install (safety net) guarantees the Cypress 12 binary lands in /opt/cypress-cache.
• rm -rf node_modules right after — the caches are what we want to keep, the extracted node_modules is rebuilt in the Jenkins workspace at runtime.
• chmod -R a+rwX /opt/yarn-cache /opt/cypress-cache /opt/app so the non-root user that Jenkins runs the container as can read/write the caches
• Dropped the redundant npm install --save-dev cypress line — Cypress is already installed via yarn install from the lockfile.

New .dockerignore

Trims the build context sent to the Docker daemon (excludes node_modules, .git, Cypress screenshots/videos, allure reports, IDE folders, logs, local env files, etc.). Speeds up builds; doesn't affect image contents since we only COPY package.json and yarn.lock.

How It Works Now

1. Image build (one-time per lockfile change):

   • Yarn downloads every tarball into /opt/yarn-cache.
   • Cypress downloads its binary into /opt/cypress-cache.
   • Both caches are chmod'd world-writable and shipped inside the image.

2. FSE Jenkins runtime (every job run):

   • Container starts with YARN_CACHE_FOLDER and CYPRESS_CACHE_FOLDER env vars already pointing at the baked-in caches.
   • yarn install in the workspace hits the local cache — no network fetches of package tarballs.
   • Cypress verifies its executable from /opt/cypress-cache — no binary download.
   • Jenkins job should complete the "install" phase in seconds instead of the previous multi-minute download.

Tradeoffs

Aspect	Before	After
Per-run install time	Minutes (full download)	Seconds (cache hit)
Image size	Baseline	~2× larger (yarn cache + Cypress binary)
Rebuild trigger	Never (deps fetched at runtime)	On package.json / yarn.lock change
Network at test time	Required	Not required for deps

The image size increase is intentional: we shifted the download cost from every Jenkins run into image storage. The one-time layer pull is amortized across all subsequent job runs.