Multiple services (#13)

Author: shivaraj-bh

README.md

@@ -16,7 +16,6 @@ TODO
 
 ## Services available
 
-- [x] Hello World
 - [x] PostgreSQL
 - [ ] MySQL
 - [x] Redis

example/flake.lock

@@ -27,7 +27,7 @@
               inputs.services-flake.processComposeModules.default
             ];
 
-            services.postgres = {
+            services.postgres."pg1" = {
               enable = true;
               listen_addresses = "127.0.0.1";
               initialDatabases = [
@@ -38,23 +38,29 @@
               ];
             };
 
+            services.postgres."pg2" = {
+              enable = true;
+              listen_addresses = "127.0.0.1";
+              port = 5433;
+            };
+
             settings.processes.pgweb =
               let
-                pgcfg = config.services.postgres;
+                pgcfg = config.services.postgres.pg1;
               in
               {
                 environment.PGWEB_DATABASE_URL = "postgres://$USER@${pgcfg.listen_addresses}:${builtins.toString pgcfg.port}/${dbName}";
                 command = pkgs.pgweb;
-                depends_on."postgres".condition = "process_healthy";
+                depends_on."pg1".condition = "process_healthy";
               };
 
             # Set this attribute and get NixOS VM tests, as a flake check, for free.
             testScript = ''
               # FIXME: pgweb is still pending, but only in VM tests for some reason.
               process_compose.wait_until(lambda procs:
-                procs["postgres"]["status"] == "Running"
+                procs["pg1"]["status"] == "Running"
               )
-              machine.succeed("echo 'SELECT version();' | ${config.services.postgres.package}/bin/psql -h 127.0.0.1 -U tester ${dbName}")
+              machine.succeed("echo 'SELECT version();' | ${config.services.postgres.pg1.package}/bin/psql -h 127.0.0.1 -U tester ${dbName}")
             '';
           };
       };

example/flake.nix

@@ -1,6 +1,39 @@
+{ pkgs, lib, ... }:
+let
+  # Create an attrsOf module wrapper (`services.${name}`) around the given submodule.
+  #
+  # where module filename is of form `${name}.nix`. The submodule takes this
+  # 'name' parameter, and is expected to set the final process-compose config in
+  # its `outputs.settings` option.
+  multiService = mod:
+    let
+      # Derive name from filename
+      name = lib.pipe mod [
+        builtins.baseNameOf
+        (lib.strings.splitString ".")
+        builtins.head
+      ];
+    in
+    { config, ... }: {
+      options.services.${name} = lib.mkOption {
+        description = ''
+          ${name} service
+        '';
+        default = { };
+        type = lib.types.attrsOf (lib.types.submoduleWith {
+          specialArgs = { inherit pkgs; };
+          modules = [ mod ];
+        });
+      };
+      config.settings.imports =
+        lib.pipe config.services.${name} [
+          (lib.filterAttrs (_: cfg: cfg.enable))
+          (lib.mapAttrsToList (_: cfg: cfg.outputs.settings))
+        ];
+    };
+in
 {
-  imports = [
-    ./hello.nix
+  imports = builtins.map multiService [
     ./postgres.nix
     ./redis.nix
   ];