pnpm

pnpm is the recommended package manager of choice for TypeScript projects at SEEK.

This topic details how to use pnpm with skuba.

Background

skuba serves as a wrapper for numerous developer tools such as TypeScript, Jest, Prettier & ESLint, abstracting the dependency management of those packages across SEEK projects. When you are using skuba, you do not need to declare these packages as direct devDependencies. In our previously-recommended package manager, Yarn, these packages and others are automatically hoisted to create a flattened dependency tree.

{
  "devDependencies": {
    "skuba": "7.2.0"
  }
}

node_modules
├── jest
├── prettier
├── skuba
└── other-skuba-deps

However, this behaviour can lead to some silly bugs when updating packages.

pnpm in skuba

pnpm addresses the hoisting issue with a symlinked structure. Each package is guaranteed to resolve compatible versions of its dependencies, rather than whichever versions were incidentally hoisted.

This behaviour is a double-edged sword for a toolkit like skuba. Dependencies like Prettier and ESLint end up nested in a node_modules/skuba/node_modules subdirectory, where most editor and developer tooling integrations will not know to look.

node_modules
├── skuba -> ./.pnpm/skuba@7.2.0
└── .pnpm
    ├── skuba@7.2.0
    │   └── node_modules
    │       └── prettier -> ../../prettier@3.0.0
    └── prettier@3.0.0
        └── node_modules
            └── other-dep -> <store>/other-dep

.npmrc

pnpm allows us to specify dependencies to hoist via command line or .npmrc. The number of package patterns we need to hoist may fluctuate over time, so specifying hoist patterns via command line would be difficult to maintain.

The skuba-maintained .npmrc currently instructs pnpm to hoist the following dependencies:

# managed by skuba
public-hoist-pattern[]="@types*"
public-hoist-pattern[]="*eslint*"
public-hoist-pattern[]="*prettier*"
public-hoist-pattern[]="esbuild"
public-hoist-pattern[]="jest"
public-hoist-pattern[]="tsconfig-seek"
# end managed by skuba

From the previous example, this will produce the following node_modules layout, allowing external integrations to find prettier in node_modules/prettier as before.

node_modules
├── prettier -> ./.pnpm/prettier@3.0.0
├── skuba -> ./.pnpm/skuba@7.2.0
└── .pnpm
    ├── skuba@7.2.0
    │   └── node_modules
    │       └── prettier -> ../../prettier@3.0.0
    └── prettier@3.0.0
        └── node_modules
            └── other-dep -> <store>/other-dep

Committing pnpm configuration in .npmrc can conflict with build pipelines that synthesise an ephemeral .npmrc to access private SEEK packages on the npm registry. A solution to this problem is detailed in the migration guide below.

Migrating from Yarn 1.x to pnpm

This migration guide assumes that your project was scaffolded with a skuba template.

Install skuba 7.4.0 or greater
Install pnpm

Run the following on macOS:
```
brew install pnpm
```
(Check the install guide for other operating systems.)
Add a packageManager key to package.json
```
"packageManager": "pnpm@9.0.5",
```
Create pnpm-workspace.yaml

Skip this step if your project does not use Yarn workspaces.
```
packages:
  # all packages in direct subdirectories of packages/
  - 'packages/*'
```
(Optional) If your sub-package package.jsons reference one another using the syntax foo: *, you can replace these references with the workspace protocol using the syntax foo: workspace:*.
Run pnpm import && rm yarn.lock

This converts yarn.lock to pnpm-lock.yaml.
Run pnpm skuba format

This will synthesise managed hoist patterns into .npmrc.

Include additional hoisting settings in .npmrc

Skip this step if your project does not use Serverless.

# managed by skuba
public-hoist-pattern[]="@types*"
public-hoist-pattern[]="*eslint*"
public-hoist-pattern[]="*prettier*"
public-hoist-pattern[]="esbuild"
public-hoist-pattern[]="jest"
public-hoist-pattern[]="tsconfig-seek"
# end managed by skuba
+
+ # Required for Serverless packaging
+ node-linker=hoisted
+ shamefully-hoist=true

Remove the .npmrc ignore entry from .gitignore and .dockerignore

Heed the warning and ensure that a safe .npmrc is included in the same commit.

yarn-error.log
# end managed by skuba
-
- # Ignore .npmrc. This is no longer managed by skuba as pnpm projects use a managed .npmrc.
- # IMPORTANT: if migrating to pnpm, remove this line and add an .npmrc IN THE SAME COMMIT.
- # You can use `skuba format` to generate the file or otherwise commit an empty file.
- # Doing so will conflict with a local .npmrc and make it more difficult to unintentionally commit auth secrets.
- .npmrc

Run rm -rf node_modules && pnpm install

This will ensure your local workspace will not have any lingering hoisted dependencies from yarn.

If you have a monorepo, delete all sub-package node_modules directories.
Run pnpm skuba lint

After running pnpm install, you may notice that some module imports no longer work. This is intended behaviour as these packages are no longer hoisted by default. Explicitly declare these as dependencies or devDependencies in package.json.

For example:
```
Cannot find module 'foo'. Did you mean to set the 'moduleResolution' option to 'nodenext', or to add aliases to the 'paths' option? ts(2792)
```
Run pnpm install foo to resolve this error.
Modify Dockerfile or Dockerfile.dev-deps

Your build pipeline may have previously mounted an ephemeral .npmrc with an auth token at /workdir. This needs to be mounted elsewhere to avoid overwriting the new pnpm configuration stored in .npmrc.
```
  FROM --platform=arm64 node:20-alpine AS dev-deps
    
+ RUN --mount=type=bind,source=package.json,target=package.json \
+ corepack enable pnpm && corepack install
    
+ RUN pnpm config set store-dir /root/.pnpm-store
    
  WORKDIR /workdir
    
- COPY package.json yarn.lock ./
- COPY packages/foo/package.json packages/foo/
    
- RUN --mount=type=secret,id=npm,dst=/workdir/.npmrc \
-     yarn install --frozen-lockfile --ignore-optional --non-interactive
+ RUN --mount=type=bind,source=.npmrc,target=.npmrc \
+     --mount=type=bind,source=pnpm-lock.yaml,target=pnpm-lock.yaml \
+     --mount=type=secret,id=npm,dst=/root/.npmrc,required=true \
+     pnpm fetch
```
Move the dst of the ephemeral .npmrc from /workdir/.npmrc to /root/.npmrc, and use a bind mount in place of COPY to mount pnpm-lock.yaml.

pnpm fetch does not require package.json to be copied to resolve packages; trivial updates to package.json like a change in scripts will no longer result in a cache miss. pnpm fetch is also optimised for monorepos and does away with the need to copy nested package.jsons. However, this command only serves to populate a local package store and stops short of installing the packages, the implications of which are covered in the next step.

Review Dockerfile.dev-deps from the new koa-rest-api template as a reference point.

Replace yarn with pnpm in Dockerfile

As pnpm fetch does not actually install packages, run a subsequent pnpm install --offline before any command which may reference a dependency. Swap out yarn commands for pnpm commands, and drop the unnecessary AS deps stage.

- FROM ${BASE_IMAGE} AS deps
-
- RUN yarn install --ignore-optional --ignore-scripts --non-interactive --offline --production
-
- ###
-
  FROM ${BASE_IMAGE} AS build
    
  COPY . .
    
- RUN yarn build
+ RUN pnpm install --offline
+ RUN pnpm build
+ RUN pnpm install --offline --prod
    
  ###
    
  FROM --platform=arm64 gcr.io/distroless/nodejs20-debian12 AS runtime
  WORKDIR /workdir
    
  COPY --from=build /workdir/lib lib
-
- COPY --from=deps /workdir/node_modules node_modules
+ COPY --from=build /workdir/node_modules node_modules
    
  ENV NODE_ENV=production

Modify plugins in .buildkite/pipeline.yml

Your build pipeline may have previously output an ephemeral .npmrc with an auth token on the build agent. This needs to be output elsewhere to avoid overwriting the new pnpm configuration stored in .npmrc.

Swap out caching on yarn.lock for .npmrc and pnpm-lock.yaml at the same time.

We are also using an updated caching syntax on package.json which caches only on the packageManager key. This requires the seek-oss/docker-ecr-cache plugin version to be >= 2.2.0.
```
  seek-oss/private-npm#v1.2.0:
    env: NPM_READ_TOKEN
+   output-path: tmp/
```
```
- seek-oss/docker-ecr-cache#v2.1.0:
+ seek-oss/docker-ecr-cache#v2.2.0:
    cache-on:
+     - .npmrc
-     - package.json
+     - package.json#.packageManager
-     - yarn.lock
+     - pnpm-lock.yaml
    dockerfile: Dockerfile.dev-deps
-   secrets: id=npm,src=.npmrc
+   secrets: id=npm,src=tmp/.npmrc
```

Run pnpm install --offline and replace yarn with pnpm in .buildkite/pipeline.yml

 - label: 🧪 Test & Lint
   commands:
+    - echo '--- pnpm install --offline'
+    - pnpm install --offline
-    - echo '+++ yarn test:ci'
-    - yarn test:ci
-    - echo '--- yarn lint'
-    - yarn lint
+    - echo '+++ pnpm test:ci'
+    - pnpm test:ci
+    - echo '--- pnpm lint'
+    - pnpm lint

FAQ

Q: I’m running into ERR_PNPM_CANNOT_DEPLOY A deploy is only possible from inside a workspace

A: pnpm deploy is a reserved command. Use pnpm run deploy instead.

Search for other references to yarn in your project. Replace these with pnpm where necessary.

Contributing

This guide is not comprehensive just yet, and it may not account for certain intricacies of your project.

If you run into an issue that is not documented here, please start a discussion or contribute a change so others can benefit from your findings. This page may be edited on GitHub.