Incrm - Angular Admin Template & Starter

AI Chat

Today

Zoneless change detection migration Pricing page copy for the Team plan

Yesterday

Postgres index not being used Q3 board update outline

Previous 7 days

Dockerfile build cache is thrashing Rewriting the onboarding email sequence Explaining OAuth PKCE to the team Hiring plan for the platform team

Dockerfile build cache is thrashing

Every CI build reinstalls all node modules even when only source files changed. What am I doing wrong?

Almost certainly you are copying the whole working tree before installing. That makes the install layer depend on every file in the repo, so any source edit invalidates it.

Copy only the manifest and lockfile first, install, then copy the rest.

dockerfile

FROM node:22-alpine
WORKDIR /app

COPY package.json package-lock.json ./
RUN npm ci

COPY . .
RUN npm run build

With that ordering a source-only change reuses the install layer and the build drops to whatever your bundler costs. If CI still misses the cache, the runner is probably starting from an empty layer store, and you need to enable a registry-backed cache explicitly.

bash

docker buildx build \
  --cache-from type=registry,ref=ghcr.io/acme/app:cache \
  --cache-to type=registry,ref=ghcr.io/acme/app:cache,mode=max \
  -t ghcr.io/acme/app:latest .

What does mode=max buy me over the default?

The default only exports the layers of the final image. mode=max also exports intermediate layers, which is exactly what you need for a multi-stage build where the expensive work happens in a stage that gets discarded.

The trade-off is cache size and push time. On a small image it is free, on a large monorepo image it can add a minute to every build, so measure before you keep it.

AI can make mistakes. Check important info.