core/pkgs/build-support/writers/data.nix

{
  lib,
  pkgs,
  formats,
  runCommand,
}:
let
  inherit (lib) last optionalString types;
in
{
  /**
    Creates a transformer function that writes input data to disk, transformed
    by both the `input` and `output` arguments.

    # Example

    ```nix
    writeJSON = makeDataWriter { input = builtins.toJSON; output = "cp $inputPath $out"; };
    myConfig = writeJSON "config.json" { hello = "world"; }
    ```

    # Type

    ```
    makeDataWriter :: input -> output -> nameOrPath -> data -> (any -> string) -> string -> string -> any -> derivation

    input :: T -> string: function that takes the nix data and returns a string
    output :: string: script that takes the $inputFile and write the result into $out
    nameOrPath :: string: if the name contains a / the files gets written to a sub-folder of $out. The derivation name is the basename of this argument.
    data :: T: the data that will be converted.
    ```
  */
  makeDataWriter = lib.warn "pkgs.writers.makeDataWriter is deprecated. Use pkgs.writeTextFile." (
    {
      input ? lib.id,
      output ? "cp $inputPath $out",
    }:
    nameOrPath: data:
    assert
      (types.path.check nameOrPath)
      || (builtins.match "([0-9A-Za-z._])[0-9A-Za-z._-]*" nameOrPath != null);
    let
      name = last (builtins.split "/" nameOrPath);
    in
    runCommand name
      {
        input = input data;
        passAsFile = [ "input" ];
      }
      ''
        ${output}

        ${optionalString (types.path.check nameOrPath) ''
          mv $out tmp
          mkdir -p $out/$(dirname "${nameOrPath}")
          mv tmp $out/${nameOrPath}
        ''}
      ''
  );

  inherit (pkgs) writeText;

  /**
    Writes the content to a JSON file.

    # Example

    ```nix
    writeJSON "data.json" { hello = "world"; }
    ```
  */
  writeJSON = (pkgs.formats.json { }).generate;

  /**
    Writes the content to a TOML file.

    # Example

    ```nix
    writeTOML "data.toml" { hello = "world"; }
    ```
  */
  writeTOML = (pkgs.formats.toml { }).generate;

  /**
    Writes the content to a YAML file.

    # Example

    ```nix
    writeYAML "data.yaml" { hello = "world"; }
    ```
  */
  writeYAML = (pkgs.formats.yaml { }).generate;
}