----------------- [![Build Status](https://travis-ci.org/google/nixery.svg?branch=master)](https://travis-ci.org/google/nixery) **Nixery** is a Docker-compatible container registry that is capable of transparently building and serving container images using [Nix][]. Images are built on-demand based on the *image name*. Every package that the user intends to include in the image is specified as a path component of the image name. The path components refer to top-level keys in `nixpkgs` and are used to build a container image using a [layering strategy][] that optimises for caching popular and/or large dependencies. A public instance as well as additional documentation is available at [nixery.dev][public]. The project started out inspired by the [buildLayeredImage][] blog post with the intention of becoming a Kubernetes controller that can serve declarative image specifications specified in CRDs as container images. The design for this was outlined in [a public gist][gist]. This is not an officially supported Google project. ## Demo Click the image to see an example in which an image containing an interactive shell and GNU `hello` is downloaded. [![asciicast](https://asciinema.org/a/262583.png)](https://asciinema.org/a/262583?autoplay=1) To try it yourself, head to [nixery.dev][public]! The special meta-package `shell` provides an image base with many core components (such as `bash` and `coreutils`) that users commonly expect in interactive images. ## Feature overview * Serve container images on-demand using image names as content specifications Specify package names as path components and Nixery will create images, using the most efficient caching strategy it can to share data between different images. * Use private package sets from various sources In addition to building images from the publicly available Nix/NixOS channels, a private Nixery instance can be configured to serve images built from a package set hosted in a custom git repository or filesystem path. When using this feature with custom git repositories, Nixery will forward the specified image tags as git references. For example, if a company used a custom repository overlaying their packages on the Nix package set, images could be built from a git tag `release-v2`: `docker pull nixery.thecompany.website/custom-service:release-v2` * Efficient serving of image layers from Google Cloud Storage After building an image, Nixery stores all of its layers in a GCS bucket and forwards requests to retrieve layers to the bucket. This enables efficient serving of layers, as well as sharing of image layers between redundant instances. ## Configuration Nixery supports the following configuration options, provided via environment variables: * `BUCKET`: [Google Cloud Storage][gcs] bucket to store & serve image layers * `PORT`: HTTP port on which Nixery should listen * `NIXERY_CHANNEL`: The name of a Nix/NixOS channel to use for building * `NIXERY_PKGS_REPO`: URL of a git repository containing a package set (uses locally configured SSH/git credentials) * `NIXERY_PKGS_PATH`: A local filesystem path containing a Nix package set to use for building * `NIX_TIMEOUT`: Number of seconds that any Nix builder is allowed to run (defaults to 60 * `GCS_SIGNING_KEY`: A Google service account key (in PEM format) that can be used to sign Cloud Storage URLs * `GCS_SIGNING_ACCOUNT`: Google service account ID that the signing key belongs to ## Roadmap ### Kubernetes integration It should be trivial to deploy Nixery inside of a Kubernetes cluster with correct caching behaviour, addressing and so on. See [issue #4](https://github.com/google/nixery/issues/4). [Nix]: https://nixos.org/ [layering strategy]: https://storage.googleapis.com/nixdoc/nixery-layers.html [gist]: https://gist.github.com/tazjin/08f3d37073b3590aacac424303e6f745 [buildLayeredImage]: https://grahamc.com/blog/nix-and-layered-docker-images [public]: https://nixery.dev [gcs]: https://cloud.google.com/storage/