https://github.com/srid/devour-flake

Devour all outputs in a Nix flake.
https://github.com/srid/devour-flake

nix nix-flakes

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Devour all outputs in a Nix flake.

• Host: GitHub
• URL: https://github.com/srid/devour-flake
• Owner: srid
• License: mit
• Created: 2023-04-24T17:27:28.000Z (over 1 year ago)
• Default Branch: master
• Last Pushed: 2024-09-14T03:06:10.000Z (about 2 months ago)
• Last Synced: 2024-10-11T23:49:18.215Z (about 1 month ago)
• Topics: nix, nix-flakes
• Language: Nix
• Homepage:
• Size: 146 KB
• Stars: 64
• Watchers: 2
• Forks: 2
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# devour-flake

Devour all outputs in a flake.



## Why?

Running `nix build .#a .#b ... .#z` on a flake with that many outputs can be rather slow if the evaluation of those packages are non-trivial, as is often the case when using [IFD](https://nixos.wiki/wiki/Import_From_Derivation). Nix evaluates separately for *each* of the argument (as if not using the [eval cache](https://www.tweag.io/blog/2020-06-25-eval-cache/)).

To workaround this, we create a "consumer" flake that will depend on all outputs in the given input flake, and then run `nix build` *on the* consumer flake, which will then evaluate the input flake's packages only once.

devour-flake currently detects the following flake outputs:

| Type | Output Key |

| -- | -- |

| Standard flake outputs | `packages`, `apps`, `checks`, `devShells` |

| NixOS | `nixosConfigurations.*` |

| nix-darwin | `darwinConfigurations.*` |

| home-manager | `legacyPackages.${system}.homeConfigurations.*` |

## Usage

To build all of the [nammayatri](https://github.com/nammayatri/nammayatri) flake outputs for example:

```bash

nix build github:srid/devour-flake \

  -L --no-link --print-out-paths \

  --override-input flake github:nammayatri/nammayatri

```

Pipe this to `| cachix push ` to [push all flake outputs to cachix](https://github.com/juspay/jenkins-nix-ci/commit/71003fbaaba8a17e02bc74c70504ebacc6a5818c)!

### Nix app

Add this repo as a non-flake input:

```nix

{

  inputs = {

    devour-flake.url = "github:srid/devour-flake";

    devour-flake.flake = false;

  };

}

```

Then, add an overlay entry to your nixpkgs:

```nix

{

  devour-flake = self.callPackage inputs.devour-flake { };

}

```

Use `pkgs.devour-flake` to get a convenient executable that will devour the given flake and spit out the out paths. You can then use this in CI to build all outputs of a flake.

#### `nix-build-all`

> **Note**

>

> **See also**: [nixci](https://github.com/srid/nixci), an improved version of `nix-build-all`.

For a CI-friendly command that builds all flake outputs, in addition to checking for `flake.lock` consistency, use:

```nix

{ pkgs, ... }:

pkgs.writeShellApplication {

  name = "nix-build-all";

  runtimeInputs = [

    pkgs.nix

    pkgs.devour-flake

  ];

  text = ''

    # Make sure that flake.lock is sync

    nix flake lock --no-update-lock-file

    # Do a full nix build (all outputs)

    # This uses https://github.com/srid/devour-flake

    devour-flake . "$@"

  '';

}

```

## Who uses it

- [nixci](https://github.com/srid/nixci): One command to run full Nix builds in CI or locally

- [jenkins-nix-ci](https://github.com/juspay/jenkins-nix-ci): Build all flake outputs in Jenkins, and push them to cachix.

- [cachix-push](https://github.com/juspay/cachix-push): Push all flake outputs to cachix.

- Other projects:

  - [horizon-platform](https://gitlab.horizon-haskell.net/package-sets/horizon-platform/-/merge_requests/28/diffs)