npm-lazy-mirror
A lazy mirroring local npm server.
About
This package provides a lazy mirroring option for those that:
- Don't want to mirror the entire couchDB for npmjs.org
- Don't want to setup cron jobs for those tasks
- Want to use an in-memory caching server (allocation configurable)
- Want to easily cache dist tarballs and package metadata to disk
Install
npm install -g npm-lazy-mirror
Run
With CLI flags:
npm-lazy-mirror -p <port> -a <remote_address> -b <bind_address> --cache-dir /npm-data
With a JSON configuration:
npm-lazy-mirror -C /path/to/config,json
See example/server-config.json for usage.
Note: Your remote_address configuration is important, as it is the address used when re-writing
tarball URLs in the metadata. It's certainly always best to use a DNS entry here,
rather than an IP.
Client configuration
Simply point your local npm config to the lazy mirror (permanent):
npm config set registry http://localhost:2000/
or per install:
npm i --registry http://localhost:2000 supertest
Help
Run npm-lazy-mirror -h to see a full list of options.
Features
- Caches all tarball / JSON metadata to disk
- Mirror serves files (200MB max by default) from memory, with a configurable LRU cache.
- Ability to blacklist packages by semantic versioning specification
- Option to serve stale resources while the upstream registry is offline
- Upstream resources are fetched on the fly from the remote registry, the fetching, storing and serving to the client all happen in the same request.
- Configurable with custom npm registries.
- HTTP/S proxy support
- It's Fast and stands up under load. Expect 5000+ req/s with one core.
A cold run installing express takes ~12 seconds (fetching from upstream registry on-the-fly):
npm install express 2.44s user 0.81s system 27% cpu 11.769 total
A warm run after all express assets are locally cached takes ~3 seconds:
npm install express 2.43s user 0.78s system 115% cpu 2.768 total
Implementation Caveats
You cannot use this mirror for publishing modules or user management, such requests will be forwarded to the upstream registry for processing.