add nix dev instructions

.envrc

@@ -0,0 +1 @@
+use_nix

.gitignore

@@ -55,3 +55,7 @@ deps.path*
 
 # Dev artifacts
 .elixir_ls
+db/
+.nix-hex/
+.nix-mix/
+.direnv/

README.md

@@ -19,6 +19,21 @@ This app is part of the [Bonfire](https://bonfirenetworks.org/) ecosystem and bu
 * Migrate DB when the app is running: `Bonfire.Repo.ReleaseTasks.migrate`
 * More handy commands: `make help` and `mix help`
 
+## Dev environment with Nix
+
+If you use direnv, just cd in the directory and you will have all the dependencies. If you just have nix, running `nix-shell` will set you up with a shell.
+
+You will need to create and init the db directory (keeping all your Postgres data inside this directory).
+create the db directory `initdb ./db`
+create the postgres user `createuser postgres -ds`
+create the db `createdb bonfire_dev`
+start the postgres instance `pg_ctl -l "$PGDATA/server.log" start`
+
+`mix deps.get` to get elixir dependencies
+`cd assets && npm install` to get the frontend dependencies
+`mix ecto.migrate` to get an up to date database
+`iex -S phx.server` to start the server
+check out the app on `localhost:4000` in your browser
 
 ## Copyright and License
 

shell.nix

@@ -0,0 +1,64 @@
+{ pkgs ? import <nixpkgs> { } }:
+
+with pkgs;
+
+let
+  messctl = rustPlatform.buildRustPackage rec {
+    pname = "messctl";
+    version = "0.0.1";
+
+    src = fetchFromGitHub {
+      owner = "bonfire-networks";
+      repo = pname;
+      rev = "8421d5ee91b120f1fe78fe8b123fc0fdf59609ff";
+      sha256 = "sha256-MniXkng8v30xzSC+cIZ+K6DWeJLCFDieXZioAQFU4/s=";
+    };
+    cargoSha256 = "sha256-z8SdQKME9/6O6ZRkNRI+vYZSf6fxAG4lz0Muv7876fY=";
+  };
+
+  # define packages to install with special handling for OSX
+  shellBasePackages = [
+    git
+    beam.packages.erlang.elixir_1_11
+    nodejs-15_x
+    postgresql_13
+    messctl
+    # for NIFs
+    rustfmt
+    clippy
+  ];
+
+  shellBuildInputs = shellBasePackages ++ lib.optional stdenv.isLinux inotify-tools
+    ++ lib.optionals stdenv.isDarwin
+    (with darwin.apple_sdk.frameworks; [ CoreFoundation CoreServices ]);
+
+  # define shell startup command
+  shellHooks = ''
+    # this allows mix to work on the local directory
+    mkdir -p $PWD/.nix-mix
+    mkdir -p $PWD/.nix-hex
+    export MIX_HOME=$PWD/.nix-mix
+    export HEX_HOME=$PWD/.nix-mix
+    export PATH=$MIX_HOME/bin:$PATH
+    export PATH=$HEX_HOME/bin:$PATH
+    mix local.hex --force
+    export LANG=en_US.UTF-8
+    export ERL_AFLAGS="-kernel shell_history enabled"
+
+    # postges related
+    export PGDATA="$PWD/db"
+
+    # elixir
+    export MIX_ENV=dev
+  '';
+
+in
+
+mkShell
+{
+  nativeBuildInputs = [ rustc cargo gcc ]; # for NIFs
+  buildInputs = shellBuildInputs;
+  shellHook = shellHooks;
+  RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
+}
+