yarn.build

yarn.BUILD is a plugin for Yarn 4 (berry). It uses your dependency graph to build just whats needed, when it's needed. You can setup a monorepo with a few backend packages, a server package, maybe a graphQL schema package, and a frontend package. And build it all, in the order it's needed. Then, only rebuild when something changes.

See the full docs at yarn.BUILD

To install for Yarn 4:

yarn plugin import https://yarn.build/latest

Or install any of the commands individually with

yarn plugin import https://yarn.build/latest/build
yarn plugin import https://yarn.build/latest/test

If you're upgrading the plugin the install location has changed to be under the @yarn.build namespace. If you have any yarn.build plugin previously installed you may need to remove the old one manually from .yarnrc.yml:

plugins:
  - checksum: ...                                 <-- remove this entry if both exist
    path: .yarn/plugins/@ojkelly/plugin-all.cjs   <--
    spec: 'https://yarn.build/latest'             <--
  - checksum: ...
    path: .yarn/plugins/@yarn.build/plugin-all.cjs
    spec: 'https://yarn.build/latest'

OpenTelemetry Support

yarn.build's build and test commands now come with optional OpenTelemetry (OTEL) instrumentation.

<summary>To use it, you need to run an OTEL Collector with a http receiver:</summary>

receivers:
  otlp:
    protocols:
      grpc:
      http: # this is the one we need, it defaults to port 4318

And set the appropirate envar for example OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318 if you are running the collector on the same host as you're running yarn.build.

NOTE: yarn.build doesn't currently support the grpc endpoint.

</details>

Commands

`build`

Build your package and all dependencies.

Run in the root of your project, or in a non-workspace folder to build everything.

Run in a specific workspace to build that workspace and all of its dependencies in the correct order, only rebuidling what's changed.

My builds are never cached?

Yarn build tries to guess your input and output folders based on common conventions.

If they're different you can specify them explicitly in package.json:

  "yarn.build": {
    "input": "src",
    "output": "dist"
  }

If that still doesn't work, check to see if your build script is modifying any files in your input folder. Some build tools like to mess with files like tsconfig.json and others.

The most ideal state is that your input folder is never modified by your build step. If this continues to happen, you should try to adjust the build scripts, or workspace layout to avoid it.

As this is fundemental to ensuring sound builds, yarn build will never cache the input folder if it's changed.

Exclude

Pass --exclude or --exclude-current to selectively exclude packages from being built.

Pass -v for verbose to get a print out of which packages were skipped or excluded.

yarn build --exclude packages/example/lorem-ipsum
yarn build --exclude packages/example/*

# Globs for package names work too, but you need to quote them so your shell doesn't try to substitute it
yarn build --exclude "@internal*"


# For Dev
# this one is really useful at the start of a dev command or similar where you
# are watching for changes in the current workspace but need to ensure your
# dependencies are built
yarn build --exclude-current

NOTE: if you explicitly exclude a workspace that another workspace depends on, and that workspace is being built the command may fail.

Git / CI integration

Use the flag --changes, to ignore the build cache, and build everything with changes staged or in the last commit.

Use --since-branch main to ignore the build cache, and build everything with changes based on what git says is different between the current branch and main (or another branch of your choosing).

Use --since ${COMMIT_HASH} to ignore the build cache, and build everything with changes between the current commit and the provided one.

`query`

Run yarn build query from within a package to see the dependency graph of what might be built.

Query doesn't currently show what's cached / needs to be rebuilt.

`test`

Test your package and it's dependencies.

Config

By default yarn.build looks at your package.json and chooses some reasonable defaults.

{
  "name": "@internal/lorem-ipsum",
  "version": "1.0.0",
  "main": "build/index.js",
  "license": "UNLICENSED",
  "private": true,
  "scripts": {
    "build": "tsc",
    "test": "jest"
  }
}

When you specify main yarn.build will exclude that folder from the build tracker, and use the package root (the same directory as the package.json) as the input folder to track.

If you want to customise the input and output folders per package you can setup a package.json as follows:

{
  "name": "@internal/lorem-ipsum",
  "version": "1.0.0",
  "license": "UNLICENSED",
  "private": true,
  "scripts": {
    "build": "tsc -outDir dist",
    "test": "jest"
  },
  "yarn.build": {
    "input": ".",
    "output": "dist"
  }
}

Troubleshooting

<details> <summary>**The output is interlaced, or mangled, or not useful in CI**</summary>

yarn.build uses is-ci to check if it's running in a CI environment, and will not print progress in the same way it does when run locally (or with an interactive tty).

Typically is-ci is really good at detecting a CI environment. It does this by checking a for one of many known environment variables set by CI tools. Including the most common and most useful fallback CI=true.

If you run yarn build or yarn test wrapped inside another execution environment inside your CI pipeline, you might need to pass an environment variable (ENV) to let yarn.build know it's being run in CI.

Depending on how your script is run, you can do something like the following:

CI=true yarn build

Adapted for Docker / BuildKit, the following will set CI for the script, but not the whole container. See issue #5 for more information

RUN env CI=true yarn build