Enable Prometheus/Grafana/Loki

modules/promtail/default.nix

@@ -0,0 +1,54 @@
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}: let
+  conf = {
+    server = {
+      http_listen_port = 28183;
+      grpc_listen_port = 0;
+    };
+    clients = [
+      {
+        url = "http://sisko.fleet:${builtins.toString config.services.loki.configuration.server.http_listen_port}/loki/api/v1/push";
+      }
+    ];
+    positions = {
+      filename = "/tmp/positions.yaml";
+    };
+    scrape_configs = [
+      {
+        job_name = "journal";
+        journal = {
+          max_age = "12h";
+          labels = {
+            job = "systemd-journal";
+            host = config.networking.hostName;
+          };
+        };
+        relabel_configs = [
+          {
+            source_labels = ["__journal__systemd_unit"];
+            target_label = "unit";
+          }
+        ];
+      }
+    ];
+  };
+  configFile = pkgs.writeTextFile {
+    name = "promtail.yaml";
+    text = lib.generators.toYAML {} conf;
+  };
+in {
+  systemd.services.promtail = {
+    description = "Promtail service for Loki";
+    wantedBy = ["multi-user.target"];
+
+    serviceConfig = {
+      ExecStart = ''
+        ${pkgs.grafana-loki}/bin/promtail --config.file ${configFile}
+      '';
+    };
+  };
+}