Getting started example project (#274)

* fix `nix develop` shell in template

#272

* template example from "Getting Started" documentation

A working example project put together from https://numtide.github.io/devshell/getting_started.html

.gitignore

@@ -9,4 +9,4 @@
 /dist
 
 # direnv
-/.direnv
+/.direnv

docs/getting_started.md

@@ -62,6 +62,8 @@ cd project/
 nix develop # or `direnv allow` if you want to use direnv
 ```
 
+Find `templates/gettingStartedExample` in this repository for a working example of the additional configuration below: `env`, `packages`, and `serviceGroups`.
+
 ## Adding environment variables
 
 Environment variables that are specific to the project can be added with the

templates/gettingStartedExample/.envrc

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# ^ added for shellcheck and file-type detection
+
+# Watch & reload direnv on change
+watch_file devshell.toml
+
+if [[ $(type -t use_flake) != function ]]; then
+  echo "ERROR: use_flake function missing."
+  echo "Please update direnv to v2.30.0 or later."
+  exit 1
+fi
+use flake

templates/gettingStartedExample/.gitignore

@@ -0,0 +1,3 @@
+/.direnv/
+/pgdata/*
+/.data/

templates/gettingStartedExample/devshell.toml

@@ -0,0 +1,39 @@
+# https://numtide.github.io/devshell
+# https://numtide.github.io/devshell/getting_started.html
+[[commands]]
+package = "hello"
+
+[[commands]]
+package = "go"
+
+[[commands]]
+package = "nodejs_20"
+
+[[commands]]
+package = "python311"
+
+[[env]]
+name = "GO111MODULE"
+value = "on"
+
+[devshell]
+packages = [
+  "postgresql_15",
+  "memcached",
+]
+
+[[commands]]
+name = "initPostgres"
+help = "Initialize the Postgres database"
+command = """\
+  initdb pgdata; \
+  chmod -R 700 pgdata; \
+  echo -e "Use the devshell command 'database:start'"
+  """
+
+[serviceGroups.database]
+description = "Runs a database in the background"
+[serviceGroups.database.services.postgres]
+command = "postgres -D ./pgdata"
+[serviceGroups.database.services.memcached]
+command = "memcached"

templates/gettingStartedExample/flake.nix

@@ -0,0 +1,21 @@
+{
+  description = "getting started example";
+
+  inputs.devshell.url = "github:numtide/devshell";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs = { self, flake-utils, devshell, nixpkgs }:
+    flake-utils.lib.eachDefaultSystem (system: {
+      devShell =
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+
+            overlays = [ devshell.overlays.default ];
+          };
+        in
+        pkgs.devshell.mkShell {
+          imports = [ (pkgs.devshell.importTOML ./devshell.toml) ];
+        };
+    });
+}

templates/gettingStartedExample/readme.md

@@ -0,0 +1,10 @@
+
+[Getting Started](https://numtide.github.io/devshell/getting_started.html)
+
+This example will run Postgres and Memcached natively on your machine.
+
+You may have to be a member of the `postgres` group to allow Postgres to start. Otherwise, Postgres may be unable to create its lockfile.
+
+First create the Postgres database with the devshell command `initPostgres`. This is defined in the TOML. It uses Postgres command `initdb`.
+
+Then the devshell command `database:start`.