nar-serve - Serve NAR file content directly from cache

Push your build artifacts to one place.

All the files in https://cache.nixos.org are packed in NAR files which makes them not directly accessible. This service allows to download, decompress, unpack and serve any file in the cache on the fly.

Use cases

• Avoid publishing build artifacts to both the binary cache and another service.
• Allows to share build results easily.
• Inspect the content of a NAR file.

Development

Inside the provided nix shell run:

./start-dev

This will create a small local server with live reload that emulates now.sh.

Currently, the default port is 8383. You can change it by setting the PORT environment variable, or HTTP_ADDR to also change the bind address.

Usage

Store contents can be fetched via a simple HTTP GET request.

Append any store path to the hostname to fetch and unpack it on the fly. That's it.

E.g.:

• https://serve.ntd.one/nix/store/barxv95b8arrlh97s6axj8k7ljn7aky1-go-1.12/share/go/doc/effective_go.html

NAR archives also contain information about the executable bit for each contained file. nar-serve uses a custom HTTP header named NAR-executable to indicate whether the fetched file would be executable.

Configuration

You can use the following environment variables to configure nar-serve:

Name	Default value	Description
PORT	8383	Port number on which nar-service listens
HTTP_ADDR	:$PORT	HTTP address to bind the server to. When set, takes precedence over $PORT.
NIX_CACHE_URL	https://cache.nixos.org	The URL of the Nix store from which NARs are fetched
DOMAIN	""	When set, also serve <nar-hash>.$DOMAIN paths.

Contributing

Contributions are welcome!

Before adding any new feature it might be best to first discuss them by creating a new issue in https://github.com/numtide/nar-serve/issues .

All code is licensed under the Apache 2.0 license.