Add runtime support: don't only listen on /tmp/frajtano1, script to add peer

.gitignore

@@ -28,3 +28,4 @@ frajtano-*.tar
 
 /.nix-hex
 /.nix-mix
+/result

config/runtime.exs

@@ -0,0 +1,2 @@
+import Config
+config :frajtano, listen_path: Path.expand(System.get_env("FRAJTANO_DIR")) |> Path.join("agent.sock")

default.nix

@@ -1,10 +1,12 @@
 {
+  lib,
+  pkgs,
   mixRelease,
-  fetchMixDeps,
   elixir,
-}:
-mixRelease rec {
+}: let
   pname = "frajtano";
+  pkg = mixRelease {
+    inherit pname;
     version = "0.0.1";
 
     inherit elixir;
@@ -13,12 +15,26 @@ mixRelease rec {
       name = "${pname}-source";
       filter = path: _type: baseNameOf path != "flake.nix" && baseNameOf path != "flake.lock";
     };
-  mixFodDeps = fetchMixDeps {
-    pname = "mix-deps-${pname}";
-    inherit version src;
-    sha256 = "sha256-lknkq6b1yDOLgTpR/tPEk9UKqpqQT6H1N5g15M60nCA=";
-  };
 
     ELIXIR_MAKE_CACHE_DIR = "/tmp/.elixir-make-cache";
-  meta.mainProgram = "${pname}";
-}
+    meta.mainProgram = pname;
+  };
+  script = pkgs.writeShellScriptBin pname ''
+    set -eu
+    file="$FRAJTANO_DIR/cookie"
+    (umask 077; [ -f "$file" ] || ${pkgs.coreutils}/bin/head -c 128 /dev/urandom | ${pkgs.coreutils}/bin/base64 -w0 > "$file")
+    export RELEASE_COOKIE=$(${pkgs.coreutils}/bin/cat "$file")
+    run() {
+      exec ${lib.getExe pkg} "$@"
+    }
+
+    case $1 in
+      assimilate)
+        run rpc ":ok = \"$(echo -n "$2" | ${pkgs.coreutils}/bin/base64)\" |> Base.decode64!() |> Frajtano.Agent.add_peer()"
+      ;;
+      *)
+        run "$@"
+      ;;
+    esac
+  '';
+in pkgs.symlinkJoin { name = pname; paths = [ script pkg ]; meta.mainProgram = pname; }

lib/agent.ex

@@ -49,6 +49,7 @@ defmodule Frajtano.Agent do
 
   @impl true
   def handle_call({:add_peer, path}, _from, state) do
+    # TODO: deduplicate peers by socket path
     case Peer.start(path) do
       {:ok, _} -> {:reply, :ok, state}
       {:error, error} -> {:reply, {:error, error}, state}

lib/frajtano.ex

@@ -18,7 +18,7 @@ defmodule Frajtano.Supervisor do
   def init(:ok) do
   	children = [
   	  Frajtano.Agent,
-  	  {Frajtano.Listener, ["/tmp/frajtano1"]},
+  	  {Frajtano.Listener, [Application.fetch_env!(:frajtano, :listen_path)]},
   	  {Task.Supervisor, name: Frajtano.ClientSupervisor},
   	  {DynamicSupervisor, name: Frajtano.Peer}
   	]

mix.exs

@@ -14,6 +14,7 @@ defmodule Frajtano.MixProject do
   def application do
     [
       extra_applications: [:logger],
+      env: [listen_path: nil],
       mod: {Frajtano, []}
     ]
   end