prometheus-node-exporter-ucode: add new package

This is a port of prometheus-node-exporter-lua to ucode.

Signed-off-by: Andre Heider <a.heider@gmail.com>

utils/prometheus-node-exporter-ucode/files/metrics.uc

@@ -0,0 +1,227 @@
+{%
+'use strict';
+
+import * as fs from "fs";
+import { connect } from "ubus";
+import { cursor } from "uci";
+
+function debug(...s) {
+	if (global.debug)
+		warn("DEBUG: ", ...s, "\n");
+}
+
+function puts(...s) {
+	return uhttpd.send(...s, "\n");
+}
+
+function govalue(value) {
+	if (value == Infinity)
+		return "+Inf";
+	else if (value == -Infinity)
+		return "-Inf";
+	else if (value != value)
+		return "NaN";
+	else if (type(value) in [ "int", "double" ])
+		return value;
+	else if (type(value) in [ "bool", "string" ])
+		return +value;
+
+	return null;
+}
+
+function metric(name, mtype, help, skipdecl) {
+	let func;
+	let decl = skipdecl == true ? false : true;
+
+	let yield = function(labels, value) {
+		let v = govalue(value);
+
+		if (v == null) {
+			debug(`skipping metric: unsupported value '${value}' (${name})`);
+			return func;
+		}
+
+		let labels_str = "";
+		if (length(labels)) {
+			let sep = "";
+			let s;
+			labels_str = "{";
+			for (let l in labels) {
+				if (labels[l] == null)
+					s = "";
+				else if (type(labels[l]) == "string") {
+					s = labels[l];
+					s = replace(labels[l], "\\", "\\\\");
+					s = replace(s, "\"", "\\\"");
+					s = replace(s, "\n", "\\n");
+				} else {
+					s = govalue(labels[l]);
+
+					if (!s)
+						continue;
+				}
+
+				labels_str += sep + l + "=\"" + s + "\"";
+				sep = ",";
+			}
+			labels_str += "}";
+		}
+
+		if (decl) {
+			if (help)
+				puts("# HELP ", name, " ", help);
+			puts("# TYPE ", name, " ", mtype);
+			decl = false;
+		}
+
+		puts(name, labels_str, " ", v);
+		return func;
+	};
+
+	func = yield;
+	return func;
+}
+
+function counter(name, help, skipdecl) {
+	return metric(name, "counter", help, skipdecl);
+}
+
+function gauge(name, help, skipdecl) {
+	return metric(name, "gauge", help, skipdecl);
+}
+
+function httpstatus(status) {
+	puts("Status: ", status, "\nContent-Type: text/plain; version=0.0.4; charset=utf-8\n");
+}
+
+function clockdiff(t1, t2) {
+	return (t2[0] - t1[0]) * 1000000000 + t2[1] - t1[1];
+}
+
+let collectors = {};
+
+global.handle_request = function(env) {
+	let scope = {
+		config: null,
+		fs,
+		ubus: connect(),
+		counter,
+		gauge,
+		wsplit: function(line) {
+			return split(line, /\s+/);
+		},
+		nextline: function(f) {
+			return rtrim(f.read("line"), "\n");
+		},
+		oneline: function(fn) {
+			let f = fs.open(fn);
+
+			if (!f)
+				return null;
+
+			return nextline(f);
+		},
+		poneline: function(cmd) {
+			let f = fs.popen(cmd);
+
+			if (!f)
+				return null;
+
+			return nextline(f);
+		},
+	};
+
+	if (length(collectors) < 1) {
+		httpstatus("404 No Collectors found");
+		return;
+	}
+
+	let cols = [];
+	for (let q in split(env.QUERY_STRING, "&")) {
+		let s = split(q, "=", 2);
+		if (length(s) == 2 && s[0] == "collect") {
+			if (!(s[1] in collectors)) {
+				httpstatus(`404 Collector ${s[1]} not found`);
+				return;
+			}
+
+			push(cols, s[1]);
+		}
+	}
+
+	if (length(cols) > 0)
+		cols = uniq(cols);
+	else
+		cols = keys(collectors);
+
+	httpstatus("200 OK");
+
+	let duration = gauge("node_scrape_collector_duration_seconds");
+	let success = gauge("node_scrape_collector_success");
+
+	for (let col in cols) {
+		let ok = false;
+		let t1, t2;
+
+		scope["config"] = collectors[col].config;
+		t1 = clock(true);
+		try {
+			ok = call(collectors[col].func, null, scope) != false;
+		} catch(e) {
+			warn(`error running collector '${col}':\n${e.message}\n`);
+		}
+		t2 = clock(true);
+
+		duration({ collector: col }, clockdiff(t1, t2) / 1000000000.0);
+		success({ collector: col }, ok);
+	}
+};
+
+const lib = "/usr/share/ucode/node-exporter/lib";
+const opts = {
+	strict_declarations:	true,
+	raw_mode:		true,
+};
+
+let cols = fs.lsdir(lib, "*.uc");
+for (let col in cols) {
+	let func;
+	let uci = cursor();
+
+	try {
+		func = loadfile(lib + "/" + col, opts);
+	} catch(e) {
+		warn(`error compiling collector '${col}':\n${e.message}\n`);
+		continue;
+	}
+
+	let name = substr(col, 0, -3);
+	let config = uci.get_all("prometheus-node-exporter-ucode", name);
+	if (!config || config[".type"] != "collector")
+		config = {};
+	else {
+		delete config[".anonymous"];
+		delete config[".type"];
+		delete config[".name"];
+	}
+
+	collectors[name] = {
+		func,
+		config,
+	};
+}
+
+warn(`prometheus-node-exporter-ucode now serving requests with ${length(collectors)} collectors\n`);
+
+if (!("uhttpd" in global)) {
+	global.debug = true;
+
+	puts = function(...s) {
+		return print(...s, "\n");
+	};
+
+	handle_request({
+		QUERY_STRING: join("&", map(ARGV, v => "collect=" + v)),
+	});
+}
+%}