1 files changed, 142 insertions, 0 deletions
diff --git a/nixos/modules/services/misc/pghero.nix b/nixos/modules/services/misc/pghero.nix
new file mode 100644
index 000000000000..39515f10c8e1
--- /dev/null
+++ b/nixos/modules/services/misc/pghero.nix
@@ -0,0 +1,142 @@
+{ config, pkgs, lib, utils, ... }:
+let
+  cfg = config.services.pghero;
+  settingsFormat = pkgs.formats.yaml { };
+  settingsFile = settingsFormat.generate "pghero.yaml" cfg.settings;
+in
+{
+  options.services.pghero = {
+    enable = lib.mkEnableOption "PgHero service";
+    package = lib.mkPackageOption pkgs "pghero" { };
+
+    listenAddress = lib.mkOption {
+      type = lib.types.str;
+      example = "[::1]:3000";
+      description = ''
+        `hostname:port` to listen for HTTP traffic.
+
+        This is bound using the systemd socket activation.
+      '';
+    };
+
+    extraArgs = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [ ];
+      description = ''
+        Additional command-line arguments for the systemd service.
+
+        Refer to the [Puma web server documentation] for available arguments.
+
+        [Puma web server documentation]: https://puma.io/puma#configuration
+      '';
+    };
+
+    settings = lib.mkOption {
+      type = settingsFormat.type;
+      default = { };
+      example = {
+        databases = {
+          primary = {
+            url = "<%= ENV['PRIMARY_DATABASE_URL'] %>";
+          };
+        };
+      };
+      description = ''
+        PgHero configuration. Refer to the [PgHero documentation] for more
+        details.
+
+        [PgHero documentation]: https://github.com/ankane/pghero/blob/master/guides/Linux.md#multiple-databases
+      '';
+    };
+
+    environment = lib.mkOption {
+      type = lib.types.attrsOf lib.types.str;
+      default = { };
+      description = ''
+        Environment variables to set for the service. Secrets should be
+        specified using {option}`environmentFile`.
+      '';
+    };
+
+    environmentFiles = lib.mkOption {
+      type = lib.types.listOf lib.types.path;
+      default = [ ];
+      description = ''
+        File to load environment variables from. Loaded variables override
+        values set in {option}`environment`.
+      '';
+    };
+
+    extraGroups = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [ ];
+      example = [ "tlskeys" ];
+      description = ''
+        Additional groups for the systemd service.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    systemd.sockets.pghero = {
+      unitConfig.Description = "PgHero HTTP socket";
+      wantedBy = [ "sockets.target" ];
+      listenStreams = [ cfg.listenAddress ];
+    };
+
+    systemd.services.pghero = {
+      description = "PgHero performance dashboard for PostgreSQL";
+      wantedBy = [ "multi-user.target" ];
+      requires = [ "pghero.socket" ];
+      after = [ "pghero.socket" "network.target" ];
+
+      environment = {
+        RAILS_ENV = "production";
+        PGHERO_CONFIG_PATH = settingsFile;
+      } // cfg.environment;
+
+      serviceConfig = {
+        Type = "notify";
+        WatchdogSec = "10";
+
+        ExecStart = utils.escapeSystemdExecArgs ([
+          (lib.getExe cfg.package)
+          "--bind-to-activated-sockets"
+          "only"
+        ] ++ cfg.extraArgs);
+        Restart = "always";
+
+        WorkingDirectory = "${cfg.package}/share/pghero";
+
+        EnvironmentFile = cfg.environmentFiles;
+        SupplementaryGroups = cfg.extraGroups;
+
+        DynamicUser = true;
+        UMask = "0077";
+
+        ProtectHome = true;
+        ProtectProc = "invisible";
+        ProcSubset = "pid";
+        ProtectClock = true;
+        ProtectHostname = true;
+        ProtectControlGroups = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        PrivateUsers = true;
+        PrivateDevices = true;
+        RestrictRealtime = true;
+        RestrictNamespaces = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" "AF_UNIX" ];
+        DeviceAllow = [ "" ];
+        DevicePolicy = "closed";
+        CapabilityBoundingSet = [ "" ];
+        MemoryDenyWriteExecute = true;
+        LockPersonality = true;
+        SystemCallArchitectures = "native";
+        SystemCallErrorNumber = "EPERM";
+        SystemCallFilter = [ "@system-service" ];
+      };
+    };
+  };
+}