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78 lines
3.0 KiB
Markdown
78 lines
3.0 KiB
Markdown
# Flake Outputs
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In `flake.nix`, the `outputs` section defines the different outputs that a flake can
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produce during its build process. A flake can have multiple outputs simultaneously, which
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can include but are not limited to the following:
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- Nix packages: These are named `apps.<system>.<name>`, `packages.<system>.<name>`, or
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`legacyPackages.<system>.<name>`. You can build a specific package using the command
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`nix build .#<name>`.
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- Nix helper functions: These are named `lib.<name>` and serve as libraries for other
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flakes to use.
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- Nix development environments: These are named `devShells` and provide isolated
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development environments. They can be accessed using the command `nix develop`.
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- NixOS configurations: These are named `nixosConfiguration` and represent specific NixOS
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system configurations. You can activate a configuration using the command
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`nixos-rebuild switch --flake .#<name>`.
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- Nix templates: These are named `templates` and can be used as a starting point for
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creating new projects. You can generate a project using the command
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`nix flake init --template <reference>`.
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- Other user-defined outputs: These outputs can be defined by the user and may be used by
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other Nix-related tools.
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Here's an example excerpt from the NixOS Wiki that demonstrates the structure of the
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`outputs` section:
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```nix
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{
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inputs = {
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# ......
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};
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outputs = { self, ... }@inputs: {
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# Executed by `nix flake check`
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checks."<system>"."<name>" = derivation;
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# Executed by `nix build .#<name>`
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packages."<system>"."<name>" = derivation;
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# Executed by `nix build .`
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packages."<system>".default = derivation;
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# Executed by `nix run .#<name>`
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apps."<system>"."<name>" = {
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type = "app";
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program = "<store-path>";
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};
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# Executed by `nix run . -- <args?>`
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apps."<system>".default = { type = "app"; program = "..."; };
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# Formatter (alejandra, nixfmt or nixpkgs-fmt)
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formatter."<system>" = derivation;
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# Used for nixpkgs packages, also accessible via `nix build .#<name>`
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legacyPackages."<system>"."<name>" = derivation;
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# Overlay, consumed by other flakes
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overlays."<name>" = final: prev: { };
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# Default overlay
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overlays.default = {};
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# Nixos module, consumed by other flakes
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nixosModules."<name>" = { config }: { options = {}; config = {}; };
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# Default module
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nixosModules.default = {};
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# Used with `nixos-rebuild --flake .#<hostname>`
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# nixosConfigurations."<hostname>".config.system.build.toplevel must be a derivation
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nixosConfigurations."<hostname>" = {};
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# Used by `nix develop .#<name>`
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devShells."<system>"."<name>" = derivation;
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# Used by `nix develop`
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devShells."<system>".default = derivation;
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# Hydra build jobs
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hydraJobs."<attr>"."<system>" = derivation;
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# Used by `nix flake init -t <flake>#<name>`
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templates."<name>" = {
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path = "<store-path>";
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description = "template description goes here?";
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};
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# Used by `nix flake init -t <flake>`
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templates.default = { path = "<store-path>"; description = ""; };
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};
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}
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```
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