Add Loki and Promtail to Grafana module

I have no idea how this works

modules/grafana/default.nix

@@ -33,6 +33,11 @@
           type = "prometheus";
           url = "http://${config.services.prometheus.listenAddress}:${toString config.services.prometheus.port}";
         }
+        {
+          name = "Loki";
+          type = "loki";
+          url = "http://${config.services.loki.configuration.server.http_listen_address}:${toString config.services.loki.configuration.server.http_listen_port}";
+        }
       ];
     };
   };
@@ -66,4 +71,129 @@
       }
     ];
   };
+
+  services.loki = {
+    enable = true;
+
+    configuration = {
+      server = {
+        http_listen_port = 3100;
+        http_listen_address = "127.0.0.1";
+      };
+
+      auth_enabled = false;
+
+      common = {
+        instance_addr = "127.0.0.1";
+        path_prefix = "/tmp/loki";
+        storage = {
+          filesystem = {
+            chunks_directory = "/var/lib/loki/chunks";
+            rules_directory = "/var/lib/loki/rules";
+          };
+        };
+        replication_factor = 1;
+        ring = {
+          kvstore = {
+            store = "inmemory";
+          };
+        };
+      };
+
+      ingester = {
+        lifecycler = {
+          address = "127.0.0.1";
+
+          ring = {
+            kvstore = {
+              store = "inmemory";
+            };
+
+            replication_factor = 1;
+          };
+
+          final_sleep = "0s";
+        };
+
+        chunk_idle_period = "1h";
+        max_chunk_age = "1h";
+        chunk_target_size = 1048576;
+        chunk_retain_period = "30s";
+      };
+
+      schema_config = {
+        configs = [
+          {
+            from = "2025-10-20";
+            store = "tsdb";
+            object_store = "filesystem";
+            schema = "v13";
+            index = {
+              prefix = "index_";
+              period = "24h";
+            };
+          }
+        ];
+      };
+
+      limits_config = {
+        reject_old_samples = true;
+        reject_old_samples_max_age = "168h";
+      };
+
+      table_manager = {
+        retention_deletes_enabled = false;
+        retention_period = "0s";
+      };
+
+      compactor = {
+        working_directory = "/var/lib/loki";
+        compactor_ring = {
+          kvstore = {
+            store = "inmemory";
+          };
+        };
+      };
+    };
+  };
+
+  services.promtail = {
+    enable = true;
+
+    configuration = {
+      server = {
+        http_listen_port = 28183;
+        grpc_listen_port = 0;
+      };
+
+      positions = {
+        filename = "/tmp/positions.yaml";
+      };
+
+      clients = [
+        {
+          url = "http://127.0.0.1:${toString config.services.loki.configuration.server.http_listen_port}/loki/api/v1/push";
+        }
+      ];
+
+      scrape_configs = [
+        {
+          job_name = "journal";
+          journal = {
+            max_age = "12h";
+            labels = {
+              job = "systemd-journal";
+              host = "homelab";
+            };
+          };
+          relabel_configs = [
+            {
+              source_labels = [ "__journal__systemd_unit" ];
+              target_label = "unit";
+            }
+          ];
+        }
+      ];
+    };
+  };
 }