add promtail log shipping

nixos/components/monitor/default.nix

@@ -14,6 +14,7 @@ with types;
     ./netdata.nix
     ./opentelemetry.nix
     ./prometheus.nix
+    ./promtail.nix
     ./telegraf.nix
   ];
 

nixos/components/monitor/opentelemetry.nix

@@ -62,9 +62,9 @@ in
           pipelines.metrics = {
             exporters = [ "otlp" ];
           };
-          #pipelines.logs = {
-          #  exporters = [ "otlp" ];
-          #};
+          pipelines.logs = {
+            exporters = [ "otlp" ];
+          };
         };
       };
     })
@@ -77,9 +77,9 @@ in
           pipelines.metrics = {
             receivers = [ "otlp" ];
           };
-          #pipelines.logs = {
-          #  exporters = [ "otlp" ];
-          #};
+          pipelines.logs = {
+            receivers = [ "otlp" ];
+          };
         };
       };
     })

nixos/components/monitor/promtail.nix

@@ -0,0 +1,67 @@
+{ config, lib, ... }:
+with lib;
+with types;
+let
+  cfg = config.components.monitor.promtail;
+in
+{
+  options.components.monitor.promtail = {
+    enable = mkOption {
+      type = lib.types.bool;
+      default = config.components.monitor.enable;
+    };
+    port = mkOption {
+      type = int;
+      default = 3500;
+      description = "port to provide promtail export";
+    };
+  };
+
+  config = mkMerge [
+
+    (mkIf config.components.monitor.promtail.enable {
+
+      services.opentelemetry-collector.settings = {
+        receivers.loki = {
+          protocols.http.endpoint = "127.0.0.1:${toString cfg.port}";
+          use_incoming_timestamp = true;
+        };
+        service.pipelines.logs.receivers = [ "loki" ];
+      };
+
+      services.promtail = {
+        enable = true;
+        configuration = {
+          server = {
+            http_listen_port = 28183;
+            grpc_listen_port = 0;
+          };
+
+          positions.filename = "/tmp/positions.yaml";
+          clients = [
+            { url = "http://127.0.0.1:${toString cfg.port}/loki/api/v1/push"; }
+          ];
+
+          scrape_configs = [
+            {
+              job_name = "journal";
+              journal = {
+                max_age = "12h";
+              };
+              relabel_configs = [
+                {
+                  source_labels = [ "__journal__systemd_unit" ];
+                  target_label = "unit";
+                }
+                {
+                  source_labels = [ "__journal__transport" ];
+                  target_label = "transport";
+                }
+              ];
+            }
+          ];
+        };
+      };
+    })
+  ];
+}