Refactor OpenWRT configuration: add host argument and correct optional flag

OpenWRT/example.alloy

@@ -4,7 +4,8 @@ import.file "openwrt" {
 }
 
 openwrt.openwrt {
-    forward_to = [prometheus.remote_write.metrics_service.receiver]
+	forward_to = [prometheus.remote_write.metrics_service.receiver]
+	host = "NAMU-PC" // Default host, can be overridden by environment variable
 }
 
 prometheus.remote_write "metrics_service" {

OpenWRT/openwrt.alloy

@@ -1,7 +1,51 @@
+import.http "libstd" {
+	url = "https://git.kkarolis.lt/karolis/Alloy/raw/branch/main/lib/std.alloy"
+}
+
 declare "openwrt" {
 	argument "forward_to" {
-		optinal = false
-		comment = "Where to forward the scraped metrics"
+		optional = false
+		comment  = "Where to forward the scraped metrics"
 	}
 
-}
+	argument "host" {
+		optional = true
+		comment  = "The host OpenWRT collector is running on"
+		default  = sys.env("GCLOUD_FM_COLLECTOR_ID")
+	}
+
+	libstd.load_host_config "load_config" {
+		host        = argument.host.value
+		config_file = "OpenWRT/config.yaml"
+	}
+
+	discovery.relabel "openwrt_node_exporter" {
+		targets = libstd.load_host_config.load_config.config.targets
+
+		rule {
+			source_labels = ["hostname"]
+			target_label  = "__address__"
+			replacement   = "$1:9100"
+		}
+
+		rule {
+			action      = "labelmap"
+			regex       = "hostname"
+			replacement = "instance"
+		}
+
+		rule {
+			action = "labeldrop"
+			regex  = "hostname"
+		}
+	}
+
+	prometheus.scrape "openwrt_node_exporter" {
+		targets    = discovery.relabel.openwrt_node_exporter.output
+		forward_to = argument.forward_to.value
+	}
+
+	export "targets" {
+		value = discovery.relabel.openwrt_node_exporter.output
+	}
+}