Official NixOS Wiki

Flakes: Difference between revisions

← Older edit
VisualWikitext
Ardenet (talk | contribs)
1,779 edits
No edit summary
Pigeon (talk | contribs)
16 edits
m →Development shells: fix code block formatting
 
(3 intermediate revisions by 2 users not shown)
Line 13: Line 13:
Flakes also allow for locking references and versions, which can then be queried and updated programatically via the inputs {{cite manual|nix|command-ref/new-cli/nix3-flake-lock|number=7.5.19|title=nix flake lock}}{{cite manual|nix|command-ref/new-cli/nix3-flake-info|number=7.5.17|title=nix flake info}}. Additionally, an experimental CLI utility accepts flake references for expressions that build, run, and deploy packages.{{Cite manual|nix|command-ref/new-cli/nix|number=8.5.1|title=nix}}
Flakes also allow for locking references and versions, which can then be queried and updated programatically via the inputs {{cite manual|nix|command-ref/new-cli/nix3-flake-lock|number=7.5.19|title=nix flake lock}}{{cite manual|nix|command-ref/new-cli/nix3-flake-info|number=7.5.17|title=nix flake info}}. Additionally, an experimental CLI utility accepts flake references for expressions that build, run, and deploy packages.{{Cite manual|nix|command-ref/new-cli/nix|number=8.5.1|title=nix}}


<!--T:185-->
== Flake file structure == <!--T:185-->
== Flake file structure ==


<!--T:231-->
Minimally, a flake file contains a description of the flake, a set of input dependencies and an output. You can generate a very basic flake file at any time using nix flake init. This will populate the current directory with a file called flake.nix that will contain something akin to:
Minimally, a flake file contains a description of the flake, a set of input dependencies and an output. You can generate a very basic flake file at any time using nix flake init. This will populate the current directory with a file called flake.nix that will contain something akin to:
</translate>
</translate>
Line 22: Line 22:
   description = "A very basic flake";
   description = "A very basic flake";


inputs = {
  inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
   };
   };


outputs = { self, nixpkgs }: {
  outputs = { self, nixpkgs }: {
 
    packages.x86_64-linux = {
packages.x86_64-linux.hello = nixpkgs.legacyPackages.x86_64-linux.hello;
      default = self.packages.x86_64-linux.hello;
 
      hello = nixpkgs.legacyPackages.x86_64-linux.hello;
packages.x86_64-linux.default = self.packages.x86_64-linux.hello;
    };
 
  };
};
}</nowiki>|name=flake.nix|lang=nix}}
}</nowiki>|name=flake.nix|lang=nix}}


Line 38: Line 37:
<!--T:190-->
<!--T:190-->
In the example above, you can see the description, the input specified as a GitHub repository with a specific branch (here <code>nixos/nixpkgs</code> on the <code>nixos-unstable</code> branch), and an output that makes use of the input. The output simply specifies that the flake contains one package for the x86_64 architecture called <code>hello</code>. Even if your flake's output wouldn't use its input (however, in practice, that is highly unlikely), the output still needs to be a Nix function.
In the example above, you can see the description, the input specified as a GitHub repository with a specific branch (here <code>nixos/nixpkgs</code> on the <code>nixos-unstable</code> branch), and an output that makes use of the input. The output simply specifies that the flake contains one package for the x86_64 architecture called <code>hello</code>. Even if your flake's output wouldn't use its input (however, in practice, that is highly unlikely), the output still needs to be a Nix function.
{{Note|Flakes require you to specify its outputs for each architecture separately. For more information, read the related section below.
</translate>}}


<translate>
<!--T:232-->
<!--T:191-->
{{Note|Flakes require you to specify its outputs for each architecture separately. For more information, read the related section below.}}
=== Nix configuration ===
 
=== Nix configuration === <!--T:191-->


<!--T:233-->
It is possible to override the global Nix configuration set in your <code>nix.conf</code> file for the purposes of evaluating a flake. This can be useful, for example, for setting up binary caches specific to certain projects, while keeping the global configuration untouched. The flake file can contain a nixConfig attribute with any relevant configuration settings supplied. For example, enabling the nix-community binary cache would be achieved by:
It is possible to override the global Nix configuration set in your <code>nix.conf</code> file for the purposes of evaluating a flake. This can be useful, for example, for setting up binary caches specific to certain projects, while keeping the global configuration untouched. The flake file can contain a nixConfig attribute with any relevant configuration settings supplied. For example, enabling the nix-community binary cache would be achieved by:
</translate>
</translate>
Line 61: Line 60:


<translate>
<translate>
<!--T:234-->
{{Note|If you are used to configuring your Nix settings via the NixOS configuration, these options are under <code>nix.settings</code> and not <code>nix</code>. For example, you cannot specify the automatic storage optimisation under <code>nix.optimisation.enable</code>.}}
{{Note|If you are used to configuring your Nix settings via the NixOS configuration, these options are under <code>nix.settings</code> and not <code>nix</code>. For example, you cannot specify the automatic storage optimisation under <code>nix.optimisation.enable</code>.}}


Line 125: Line 125:
Therefore, if you use <code>git</code> for your flake, ensure to <code>git add</code> any project files after you first create them.}}
Therefore, if you use <code>git</code> for your flake, ensure to <code>git add</code> any project files after you first create them.}}


<!--T:64-->
=== The nix flakes command === <!--T:64-->
=== The nix flakes command ===
</translate>
</translate>


Line 158: Line 157:
   description = "Example flake with a devShell";
   description = "Example flake with a devShell";


inputs.nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
  inputs.nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";


outputs = { self, nixpkgs}:
  outputs = { self, nixpkgs }:
     let
     let
       system = "x86_64-linux";
       system = "x86_64-linux";
Line 243: Line 242:


<translate>
<translate>
<!--T:235-->
Nixpkgs can alternatively also point to an url cached by the NixOS organization:
Nixpkgs can alternatively also point to an url cached by the NixOS organization:
</translate>
</translate>
Line 249: Line 249:


<translate>
<translate>
<!--T:236-->
In this example the input would point to the `nixpkgs-unstable` channel.
In this example the input would point to the `nixpkgs-unstable` channel.


Retrieved from "https://wiki.nixos.org/wiki/Flakes"