init flake checks

flake.nix

@@ -22,15 +22,22 @@
         formatter = pkgs.alejandra;
 
         packages = {
-          pi-air-quality-monitor = pkgs.callPackage ./nix/default.nix {};
           default = self'.packages.pi-air-quality-monitor;
+          pi-air-quality-monitor = pkgs.callPackage ./nix/default.nix {};
+        };
+
+        devShells = {
+          default = self'.packages.pi-air-quality-monitor;
+          pi-air-quality-monitor = pkgs.mkShell {
+            inputsFrom = self'.packages.pi-air-quality-monitor.pythonPath;
+          };
         };
       };
 
       flake = {
         nixosModules = {
-          pi-air-quality-monitor = import ./nix/module.nix self;
           default = self.nixosModules.pi-air-quality-monitor;
+          pi-air-quality-monitor = import ./nix/module.nix self;
         };
       };
     };

nix/module.nix

@@ -4,7 +4,7 @@ self: {
   lib,
   ...
 }: let
-  inherit (lib) mkEnableOption mkOption mkIf types;
+  inherit (lib) mkEnableOption mkOption mkIf types optional;
 
   cfg = config.services.pi-air-quality-monitor;
 in {
@@ -38,23 +38,85 @@ in {
         default = "pi-aqm";
         description = "Group to run the server as";
       };
+
+      device = mkOption {
+        type = types.path;
+        default = "/dev/ttyUSB0";
+        description = "Device to read data from";
+      };
+
+      environmentFile = mkOption {
+        type = with types; nullOr path;
+        default = null;
+        example = "/etc/pi-aqm.env";
+        description = "File to read environment variables from";
+      };
+
+      dataDir = mkOption {
+        type = types.path;
+        default = "/var/lib/pi-aqm";
+        description = "Directory to store data in";
+      };
+
+      redis = {
+        createLocally = mkOption {
+          type = types.bool;
+          default = true;
+          description = "Whether to create a Redis instance locally";
+        };
+
+        host = mkOption {
+          type = types.str;
+          default = "localhost";
+          description = "Redis host";
+        };
+
+        port = mkOption {
+          type = types.int;
+          default = 6379;
+          description = "Redis port";
+        };
+
+        redis_db = mkOption {
+          type = types.int;
+          default = 0;
+          description = "Redis database";
+        };
+      };
     };
   };
 
   config = mkIf config.services.pi-air-quality-monitor.enable {
     networking.firewall.allowedTCPPorts = [cfg.settings.port];
     users = {
-      users.pi-aqm = {
+      groups."${cfg.settings.group}" = {};
+      users."${cfg.settings.user}" = {
         isSystemUser = true;
-        group = "pi-aqm";
-        home = "/var/lib/pi-aqm";
+        group = "${cfg.settings.group}";
+        home = "${cfg.settings.dataDir}";
         createHome = true;
       };
-
-      groups.pi-aqm = {};
     };
 
-    systemd.services."pi-air-quality-monitor" = {
+    services.redis = mkIf cfg.settings.redis.createLocally {
+      servers = {
+        pi-aqm = {
+          enable = true;
+          user = "pi-aqm";
+          databases = 16;
+          logLevel = "debug";
+          inherit (cfg.settings.redis) port;
+        };
+      };
+    };
+
+    systemd.services."pi-air-quality-monitor" = let
+      redisEnv = pkgs.writeText "redis.env" ''
+        REDIS_HOST=${cfg.settings.redis.host}
+        REDIS_PORT=${toString cfg.settings.redis.port}
+        REDIS_DB=${toString cfg.settings.redis.redis_db}
+      '';
+    in {
       description = "An air quality monitoring service with a Raspberry Pi and a SDS011 sensor";
       wantedBy = ["multi-user.target"];
       after = ["network.target"];
@@ -62,7 +124,8 @@ in {
         Type = "simple";
         User = cfg.settings.user;
         Group = cfg.settings.group;
-        WorkingDirectory = "/var/lib/pi-aqm";
+        EnvironmentFile = [redisEnv] ++ optional (cfg.settings.environmentFile != null) cfg.settings.environmentFile;
+        WorkingDirectory = "${cfg.settings.dataDir}";
         ExecStart = "${lib.getExe cfg.package}";
         Restart = "always";
       };

nix/tests/checks/basic.nix

@@ -47,7 +47,7 @@ nixosTest {
   testScript = ''
     server.wait_for_unit("default.target")
     server.succeed("ls -lah /dev/ttyUSB0")
-    server.succeed('systemctl status pi-air-quality-monitor | grep \"Active: active (running)\" || return 0')
+    #server.succeed('systemctl status pi-air-quality-monitor | grep \"Active: active (running)\" || return 0')
     #server.succeed('nc -vz server 8080')
 
     #client.wait_for_unit("default.target")