prometheus-node-exporter-ucode: add a plugin for go2rtc metrics

- Add a plugin to export go2rtc metrics

Requires additional api_url option to enable:

```
uci set prometheus-node-exporter-ucode.go2rtc=collector
uci set prometheus-node-exporter-ucode.go2rtc.api_url='http://127.0.0.1:1984'
```

Signed-off-by: Vladimir Ermakov <[email protected]>

Author: vooon

utils/prometheus-node-exporter-ucode/Makefile

@@ -4,7 +4,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=prometheus-node-exporter-ucode
 PKG_VERSION:=2024.02.07
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 
 PKG_MAINTAINER:=Andre Heider <[email protected]>
 PKG_LICENSE:=Apache-2.0
@@ -72,3 +72,4 @@ $(eval $(call Collector,snmp6,snmp6 collector,))
 $(eval $(call Collector,uci_dhcp_host,UCI DHCP host collector,))
 $(eval $(call Collector,wifi,Wi-Fi collector,+ucode-mod-nl80211))
 $(eval $(call Collector,wireguard,Wireguard collector,+rpcd-mod-wireguard))
+$(eval $(call Collector,go2rtc,go2rtc collector,+uclient-fetch go2rtc))

utils/prometheus-node-exporter-ucode/files/extra/go2rtc.uc

@@ -0,0 +1,67 @@
+import * as log from "log";
+
+const api_url = config["api_url"];
+if (!api_url)
+	return false;
+
+let m_up = gauge("go2rtc_up");
+let m_producer_info = gauge("go2rtc_producer_info");
+let m_consumer_info = gauge("go2rtc_consumer_info");
+let m_producer_rx = counter("go2rtc_producer_received_bytes_total");
+let m_consumer_tx = counter("go2rtc_consumer_sent_bytes_total");
+
+
+function get_streams_info(api_url) {
+
+	const url = `${api_url}/api/streams`;
+
+	// NOTE: ucode-mod-uclient not so easy to use, also it brings problems with ujail library mount.
+	let ret = ubus.call("file", "exec", {command: "uclient-fetch", params: ["-T", "5", "-O", "-", url]});
+	if (ret?.code != 0) {
+		log.ERR("failed to fetch url: %s rc: %d: err: %s", url, ret?.code, ret?.stderr);
+		return null;
+	}
+
+	return json(ret.stdout);
+}
+
+const x = get_streams_info(api_url);
+
+if (!x) {
+	m_up({url: api_url}, 0);
+	return false;
+}
+
+m_up({url: api_url}, 1);
+
+for (let stream, info in x) {
+
+	for (let producer in info.producers) {
+		m_producer_info({
+			stream: stream,
+			format_name: producer.format_name,
+			protocol: producer.protocol,
+			remote_addr: producer.remote_addr,
+			user_agent: producer.user_agent,
+		}, (!producer.remote_addr) ? 0 : 1);
+		m_producer_rx({
+			stream: stream,
+			remote_addr: producer.remote_addr,
+		}, producer.bytes_recv);
+	}
+
+	for (let consumer in info.consumers) {
+		m_consumer_info({
+			stream: stream,
+			format_name: consumer.format_name,
+			protocol: consumer.protocol,
+			remote_addr: consumer.remote_addr,
+			user_agent: consumer.user_agent,
+		}, 1);
+		m_consumer_tx({
+			stream: stream,
+			remote_addr: consumer.remote_addr,
+		}, consumer.bytes_send);
+	}
+
+}