Nix CI Detector

This flake exposes and API to detect if Nix is run in a continuous integration(CI) environment or not. This project has been inspired by OndraM/ci-detector library for PHP.

Usage

Warning: Since detecting if we are in a CI or not rely on environment variables, we must add the flag --impure to the nix command.

In command line:

$ nix eval github:loophp/ci-detector#lib.inCI --impure
false

Now faking a Github actions environment by setting the GITHUB_ACTIONS variable:

$ GITHUB_ACTIONS="FOOBAR" nix eval github:loophp/ci-detector#lib.inCI --impure
true

API

This package contains a flake.nix which exposes an API.

Exposed API:

• lib.ci: When running in a CI, returns a set containing the current CI environment information, throws an error otherwise.
• lib.inCI: When running in a CI, returns true, false otherwise.
• lib.notInCI: When running in a CI, returns false, true otherwise.
• lib.find: Unary function where the first argument is a default value. When in a CI, the CI information is returned, otherwise the default value is returned.

To use it in your own package, take example on the following minimum working example:

{
  description = "Simple example flake";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    flake-utils.url = "github:numtide/flake-utils";
    ci-detector.url = "github:loophp/ci-detector";
  };

  outputs = { self, nixpkgs, flake-utils, ci-detector, ... }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs {
          inherit system;
        };

        ci = ci-detector.lib.find { name = "local"; };
      in
      {
        devShells.default = pkgs.mkShellNoCC {
          name = "${ci.name}-devshell";
        };
      });
}