nixcached is a CLI that provides both a caching HTTP proxy and an asynchronous build artifact upload pipeline for Nix. It can use the local filesystem, Amazon S3, Google Cloud Storage, or any S3-compatible storage like MinIO.
nixcached is distributed as a Docker image:
docker pull ghcr.io/zombiezen/nixcachedAlternatively, if you're already using Nix, you can install the binary by checking out the repository and running the following:
nix-env --file . --installOr if you're using Nix Flakes:
nix profile install github:zombiezen/nixcached/v0.3.3Otherwise, you can download a static binary from the latest release.
nixcached can be run as an HTTP proxy for another Nix store. This has a number of benefits:
- Reduces the traffic to the Nix store.
- Opens an interactive explorer UI over your Nix store.
- Allows privilege/credential separation from the Nix build process.
- Ability to use native Google Cloud credentials for Google Cloud Storage.
To run nixcached as an HTTP proxy:
# Local Nix store
nixcached serve --port=8080 /nix/store
# Local folder
mkdir "$HOME/foo" && nixcached serve --port=8080 "file://$HOME/foo"
# Amazon S3
nixcached serve --port=8080 s3://nix-cache
# S3-compatible Storage
nixcached serve --port=8080 s3://mybucket?endpoint=minio.example.com:8080&disableSSL=true&s3ForcePathStyle=true
# Google Cloud Storage (GCS)
nixcached serve --port=8080 gs://nix-cache
# Remote Nix store
nixcached serve --port=8080 ssh://example.comnixcached can be run as an upload pipeline.
This is useful for uploading build artifacts as a Nix post-build hook.
To do this, run nixcached upload
(either manually or using a service manager like systemd)
with a named pipe as input:
mkfifo /run/nixcached-upload &&
nixcached upload -k --input=/run/nixcached-upload s3://${MY_BUCKET?}Then in your post-build hook run nixcached send:
nixcached send -o /run/nixcached-upload $OUT_PATHSSending SIGHUP to nixcached upload
will prevent any new paths from being received
and cause the process to exit after it finishes copying any Nix store objects.