chore: some cleaning + logging implementation

lib/config/alloy/config.alloy.nix

@@ -0,0 +1,15 @@
+let
+  infra = import ../../constants.nix;
+in
+{
+  out = ''
+    logging {
+      level = "warning"
+    }
+    loki.write "grafana_loki" {
+      endpoint {
+        url = "http://${infra.loki_addr}/loki/api/v1/push"
+      }
+    }
+  '';
+}

lib/config/alloy/metrics.alloy.nix

@@ -0,0 +1,47 @@
+{ container_id, ... }:
+let
+  infra = import ../../constants.nix;
+in
+{
+  out = ''
+    prometheus.exporter.unix "default" {
+      include_exporter_metrics = true
+      disable_collectors       = ["mdadm"]
+    }
+
+    prometheus.scrape "default" {
+      targets = array.concat(
+        prometheus.exporter.unix.default.targets,
+        [{
+          // Self-collect metrics
+          job         = "alloy",
+          __address__ = "127.0.0.1:12345",
+        }],
+      )
+
+      forward_to = [prometheus.relabel.filter_metrics.receiver]
+      scrape_interval = "60s"
+    }
+
+    prometheus.relabel "filter_metrics" {
+      rule {
+        action = "drop"
+        source_labels = [ "env" ]
+        regex = "dev"
+      }
+      rule {
+        action = "replace"
+        regex = "127\\.0\\.0\\.1"
+        target_label = "instance"
+        replacement = "${infra.build_ip container_id}"
+      }
+      forward_to = [prometheus.remote_write.metrics_service.receiver]
+    }
+
+    prometheus.remote_write "metrics_service" {
+      endpoint {
+        url = "http://${infra.prometheus_addr}/api/v1/write"
+      }
+    }
+  '';
+}