How to use a built-in package development environment

Important

For the list of all available configuration options for development environment configuration, see the packages develop options reference.

NGI Forge provides a built-in development environment containing all dependencies required to build a package from source by running a single nix develop .#pkgs.<package-name>.env command.

Development environment

Launch a development environment for the hello-web package:

nix develop .#pkgs.hello-web.env

# or
nix-shell -A pkgs.hello-web.env default.nix

Welcome. This environment contains all dependencies required
to build hello-web from source.

Grab the source code from /nix/store/89d286yd9nj83pz0g8rq56ia6p7l588y-src
or from the upstream repository and you are all set to start hacking.

Copy the source code from the Nix store path printed above to a writable directory:

cp -r --no-preserve=mode,ownership \
  /nix/store/89d286yd9nj83pz0g8rq56ia6p7l588y-src \
  src/
cd src

Build the package:

go build -o hello-web .

Run the binary:

./hello-web
Hello, world!

Environment customization

Additional environment packages and a entry script can be configured.

For example, add the following configuration to recipes/pkgs/hello-web/recipe.nix to add the Go language linter and customize a default welcome message:

pkgs.hello-web = {
  ...
  develop = {
    packages = with pkgs; [ golangci-lint ];
    shellHook = ''
      echo
      echo "Build the $ENV_PACKAGE_NAME from source:"
      echo
      echo "  cp -r --no-preserve=mode,ownership $ENV_PACKAGE_SOURCE src/"
      echo "  cd src"
      echo
      echo "  go build -o hello-web ."
      echo
      echo "Run the linter:"
      echo
      echo "  golangci-lint run ."
    '';
  };
};

Re-launch the development environment:

nix develop .#pkgs.hello-web.env

Build hello-web from source:

  cp -r --no-preserve=mode,ownership /nix/store/89d286yd9nj83pz0g8rq56ia6p7l588y-src src/
  cd src

  go build -o hello-web .

Run the linter:

  golangci-lint run .

Run the linter:

golangci-lint run .

main.go:22:13: Error return value of `fmt.Fprint` is not checked (errcheck)
		fmt.Fprint(w, message)
		          ^
1 issues:
* errcheck: 1