prometheus-node-exporter-ucode: order output

-netdev
-netclass

Fix metric output to be ordered per-metric, and not per-device as is
done by node_exporter. In testing, netdev and netclass scrape time
increased a mean 2msec as a result of the extra loops.

In netdev, we skip some checks since the format of /proc/net/dev is
stable.

Signed-off-by: Paul Donald <newtwen+github@gmail.com>

Author: systemcrash

utils/prometheus-node-exporter-ucode/files/base/netclass.uc

@@ -1,48 +1,52 @@
 const root = "/sys/class/net/";
 const devices = fs.lsdir(root);
+const dev_length = length(devices);
 
-if (length(devices) < 1)
+if (dev_length < 1)
 	return false;
 
 const m_info = gauge("node_network_info");
 const m_speed = gauge("node_network_speed_bytes");
 const metrics = {
 	addr_assign_type:	gauge("node_network_address_assign_type"),
-	carrier:		gauge("node_network_carrier"),
+	carrier:			gauge("node_network_carrier"),
 	carrier_changes:	counter("node_network_carrier_changes_total"),
 	carrier_down_count:	counter("node_network_carrier_down_changes_total"),
 	carrier_up_count:	counter("node_network_carrier_up_changes_total"),
-	dev_id:			gauge("node_network_device_id"),
-	dormant:		gauge("node_network_dormant"),
-	flags:			gauge("node_network_flags"),
-	ifindex:		gauge("node_network_iface_id"),
-	iflink:			gauge("node_network_iface_link"),
-	link_mode:		gauge("node_network_iface_link_mode"),
-	mtu:			gauge("node_network_mtu_bytes"),
+	dev_id:				gauge("node_network_device_id"),
+	dormant:			gauge("node_network_dormant"),
+	flags:				gauge("node_network_flags"),
+	ifindex:			gauge("node_network_iface_id"),
+	iflink:				gauge("node_network_iface_link"),
+	link_mode:			gauge("node_network_iface_link_mode"),
+	mtu:				gauge("node_network_mtu_bytes"),
 	name_assign_type:	gauge("node_network_name_assign_type"),
 	netdev_group:		gauge("node_network_net_dev_group"),
-	type:			gauge("node_network_protocol_type"),
+	type:				gauge("node_network_protocol_type"),
 	tx_queue_len:		gauge("node_network_transmit_queue_length"),
 };
 
-for (let device in devices) {
-	const devroot = root + device + "/";
+for (let i = 0; i < dev_length; i++) {
+	const devroot = root + devices[i] + "/";
 
 	m_info({
-		device,
+		device: devices[i],
 		address:	oneline(devroot + "address"),
 		broadcast:	oneline(devroot + "broadcast"),
 		duplex:		oneline(devroot + "duplex"),
 		operstate:	oneline(devroot + "operstate"),
 		ifalias:	oneline(devroot + "ifalias"),
 	}, 1);
+}
 
-	for (let m in metrics) {
-		let line = oneline(devroot + m);
-		metrics[m]({ device }, line);
+for (let m in metrics) {
+	for (let i = 0; i < dev_length; i++) {
+		metrics[m]({ device: devices[i] }, oneline(root + devices[i] + "/" + m));
 	}
+}
 
-	const speed = int(oneline(devroot + "speed"));
+for (let i = 0; i < dev_length; i++) {
+	const speed = int(oneline(root + devices[i] + "/" + "speed"));
 	if (speed > 0)
-			m_speed({ device }, speed * 1000 * 1000 / 8);
+			m_speed({ device: devices[i] }, speed * 1000 * 1000 / 8);
 }

utils/prometheus-node-exporter-ucode/files/base/netdev.uc

@@ -1,9 +1,9 @@
-let f = fs.open("/proc/net/dev");
+const f = fs.open("/proc/net/dev");
 
 if (!f)
 	return false;
 
-const m = [
+const metrics = [
 	null,
 	counter("node_network_receive_bytes_total"),
 	counter("node_network_receive_packets_total"),
@@ -23,18 +23,44 @@ const m = [
 	counter("node_network_transmit_compressed_total"),
 ];
 
+// Per-counter results array
+/* results[i] = { dev1: value, dev2: value, ... } */
+let results = [];
+for (let i = 0; i < length(metrics); i++)
+	results[i] = {};
+
+// Parse file first
 let line;
-while (line = nextline(f)) {
+for (let k = 0; line = nextline(f); k++) {
+	if (k < 2)
+		continue; // skip the header lines
 	const x = wsplit(ltrim(line), " ");
 
-	if (length(x) < 2)
-		continue;
+	const dev = substr(x[0], 0, -1);
+
+	for (let i = 1; i < length(x); i++) {
+		results[i][dev] = x[i];
+	}
+}
 
-	if (substr(x[0], -1) != ":")
+// Build label objects
+let label_cache = {};
+for (let i = 1; i < length(results); i++) {
+	for (let dev in results[i]) {
+		if (!(dev in label_cache))
+			label_cache[dev] = { device: dev };
+	}
+}
+
+// Emit metrics grouped by counter
+for (let i = 1; i < length(metrics); i++) {
+	const metric = metrics[i];
+	if (!metric)
 		continue;
 
-	const count = min(length(x), length(m));
-	const labels = { device: substr(x[0], 0, -1) };
-	for (let i = 1; i < count; i++)
-		m[i](labels, x[i]);
+	for (let dev in results[i]) {
+		metric(label_cache[dev], results[i][dev]);
+	}
 }
+
+return true;