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Version: Next

Working with Docker

note

It is impossible to create reflinks or hardlinks between a Docker container and the host filesystem during build time. The next best thing you can do is using BuildKit cache mount to share cache between builds. Alternatively, you may use podman because it can mount Btrfs volumes during build time.

Minimizing Docker image size and build time​

  • Use a small image, e.g. node:XX-slim.
  • Leverage multi-stage if possible and makes sense.
  • Leverage BuildKit cache mounts.

Example 1: Build a bundle in a Docker container​

Since devDependencies is only necessary for building the bundle, pnpm install --prod will be a separate stage from pnpm install and pnpm run build, allowing the final stage to copy only necessary files from the earlier stages, minimizing the size of the final image.

.dockerignore
node_modules
.git
.gitignore
*.md
dist
Dockerfile
FROM node:20-slim AS base
ENV PNPM_HOME="/pnpm"
ENV PATH="$PNPM_HOME:$PATH"
RUN corepack enable
COPY . /app
WORKDIR /app

FROM base AS prod-deps
RUN --mount=type=cache,id=pnpm,target=/pnpm/store pnpm install --prod --frozen-lockfile

FROM base AS build
RUN --mount=type=cache,id=pnpm,target=/pnpm/store pnpm install --frozen-lockfile
RUN pnpm run build

FROM base
COPY --from=prod-deps /app/node_modules /app/node_modules
COPY --from=build /app/dist /app/dist
EXPOSE 8000
CMD [ "pnpm", "start" ]

Example 2: Build multiple Docker images in a monorepo​

Assuming you have a monorepo with 3 packages: app1, app2, and common; app1 and app2 depend on common but not each other.

Structure of the monorepo
./
├── Dockerfile
├── .dockerignore
├── .gitignore
├── packages/
│   ├── app1/
│   │   ├── dist/
│   │   ├── package.json
│   │   ├── src/
│   │   └── tsconfig.json
│   ├── app2/
│   │   ├── dist/
│   │   ├── package.json
│   │   ├── src/
│   │   └── tsconfig.json
│   └── common/
│       ├── dist/
│       ├── package.json
│       ├── src/
│       └── tsconfig.json
├── pnpm-lock.yaml
├── pnpm-workspace.yaml
└── tsconfig.json
pnpm-workspace.yaml
packages:
  - 'packages/*'
.dockerignore
node_modules
.git
.gitignore
*.md
dist
Dockerfile
FROM node:20-slim AS base
ENV PNPM_HOME="/pnpm"
ENV PATH="$PNPM_HOME:$PATH"
RUN corepack enable
COPY . /app
WORKDIR /app

FROM base AS prod-deps
RUN --mount=type=cache,id=pnpm,target=/pnpm/store pnpm install --prod --frozen-lockfile

FROM base AS build
RUN --mount=type=cache,id=pnpm,target=/pnpm/store pnpm install --frozen-lockfile
RUN pnpm run -r build

FROM base AS common
COPY --from=prod-deps /app/packages/common/node_modules/ /app/packages/common/node_modules
COPY --from=build /app/packages/common/dist /app/packages/common/dist

FROM common AS app1
COPY --from=prod-deps /app/packages/app1/node_modules/ /app/packages/app1/node_modules
COPY --from=build /app/packages/app1/dist /app/packages/app1/dist
WORKDIR /app/packages/app1
EXPOSE 8000
CMD [ "pnpm", "start" ]

FROM common AS app2
COPY --from=prod-deps /app/packages/app2/node_modules/ /app/packages/app2/node_modules
COPY --from=build /app/packages/app2/dist /app/packages/app2/dist
WORKDIR /app/packages/app2
EXPOSE 8001
CMD [ "pnpm", "start" ]

Run the following commands to build images for app1 and app2:

docker build . --target app1 --tag app1:latest
docker build . --target app2 --tag app2:latest