https://github.com/input-output-hk/capkgs

Content Addressed Packages
https://github.com/input-output-hk/capkgs

content-addressed nix

Last synced: 3 months ago
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Content Addressed Packages

• Host: GitHub
• URL: https://github.com/input-output-hk/capkgs
• Owner: input-output-hk
• License: apache-2.0
• Created: 2023-09-01T14:12:05.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2025-10-06T14:26:28.000Z (3 months ago)
• Last Synced: 2025-10-06T16:27:00.945Z (3 months ago)
• Topics: content-addressed, nix
• Language: Crystal
• Homepage:
• Size: 1.21 MB
• Stars: 6
• Watchers: 4
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Notice: NOTICE

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README

          
# Content Addressed Packages

A collection of content-addressed package closures.

## Purpose

This project aims to speed up development environment setup, reduce disk and CPU

usage, and provide a smoother onboarding experience.

That's achieved by evaluating and building, then converting them into their

content-addressed form using `nix store make-content-addressed`.

In this process, Nix calculates the hashes of the final output, as opposed

to the default where the hash is calculated based on the attributes of a

derivation.

Once the final hash is known, no other user has to download the sources and run

the evaluation steps anymore, and they can fully trust the cache if the hash

matches.

In a sense, this does for Nix programs what Nix does for other programs.

Naturally, only packages that were actually built successfully are available in this fashion.

## Usage

At the moment, this requires the experimental `fetch-closure` feature of Nix.

You can enable it using the `--extra-experimental-features` flag, or in your configuration.

Additionally, this flake will only work with the `flakes` feature, although you

may fetch the `packages.json` from this repo and use the `closure` attribute to

pass to `fetchClosure` with traditional Nix.

Packages are referenced by a `///` schema.

    {

      inputs.capkgs.url = "github:input-output-hk/capkgs";

      outputs = {capkgs, ...}: {

        packages.x86_64-linux.cardano-node =

         capkgs.packages.x86_64-linux.input-output-hk-cardano-node-8-2-0-pre-cardano-node-exe-cardano-node-8-2-0;

      };

    }

## Packages

The list of packages we provide lives in `packages.json`, only packages without

the `fail` attribute are considered. We keep the information about failed

packages around to avoid attempts of rebuilding them which would consume vast

amounts of time.

This list is derived from the `projects.json`, where we declare which packages

from which repository we would like to have.

Ideally a repository follows a sensible release process, and we can just use

that as basis for our versioning, but when that is not the case, there are other

strategies, based on tag patterns or bare branch names.

## TODO

- [ ] Provide more statically compiled `musl` packages and nuke their references to the Nix store to allow even smaller closures.

- [ ] Make the update scripts generally useful as a tool for the community.

- [ ] Improve naming of packages, although verbose, it still may have collisions.

- [ ] Run periodically on Hydra to populate our cache.

- [ ] Automatically update this repo.

- [ ] Maybe an easier way to force rebuilding specific packages.

- [ ] Record _why_ a specific package is marked as failed, not just that it did. 

- [ ] validate projects.json syntax before starting