changes for metrics tests

CountItems/CountMaster.js

@@ -1,11 +1,13 @@
 const async = require('async');
 const { reshapeExceptionError } = require('arsenal').errorUtils;
+const monitoring = require('../utils/monitoring');
 
 class CountMaster {
     constructor(params) {
         this.log = params.log;
         this.manager = params.manager;
         this.client = params.client;
+        this.metrics = params.metrics;
     }
 
     stop(signal, callback) {
@@ -34,6 +36,7 @@ class CountMaster {
                 }
                 return next();
             }),
+            next => this.metrics.start(next),
             next => this.manager.setup(next),
             next => this.client.getBucketInfos(this.log, (err, bucketList) => {
                 if (err) {
@@ -45,6 +48,7 @@ class CountMaster {
                 this.log.info('got buckets infos', {
                     bucketCount: bucketList.bucketCount,
                 });
+                monitoring.bucketCount.set(bucketList.bucketCount);
                 this.manager.addWork(bucketList);
                 return next();
             }),

CountItems/masterProcess.js

@@ -6,7 +6,9 @@ const CountMaster = require('./CountMaster');
 const CountManager = require('./CountManager');
 const createMongoParams = require('../utils/createMongoParams');
 const createWorkers = require('./utils/createWorkers');
-
+const { network } = require('arsenal');
+const WebServer = network.http.server;
+const monitoring = require('../utils/monitoring');
 const logLevel = Number.parseInt(process.env.DEBUG, 10) === 1
     ? 'debug' : 'info';
 
@@ -35,6 +37,7 @@ const countMaster = new CountMaster({
         maxConcurrent: concurrentCursors,
     }),
     client: new S3UtilsMongoClient(createMongoParams(log)),
+    metrics: new WebServer(8003, log).onRequest(monitoring.metricsHandler)
 });
 
 const handleSignal = sig => countMaster.stop(sig, () => process.exit(0));

utils/monitoring.js

@@ -0,0 +1,57 @@
+const { errors } = require('arsenal');
+const promClient = require('prom-client');
+
+const collectDefaultMetrics = promClient.collectDefaultMetrics;
+
+const bucketCount = new promClient.Gauge({
+    name: 'bucketCount_metrics',
+    help: 'Total number of buckets',
+    labelNames: ['bucketName'],
+});
+
+/**
+ * @param {http.ServerResponse} res - http response object
+ * @param {errors.ArsenalError} error - Error code
+ * @return {void}
+ */
+function _writeResponse(res, error) {
+    let statusCode = 200;
+    if (error) {
+        if (Number.isInteger(error.code)) {
+            statusCode = error.code;
+        } else {
+            statusCode = 500;
+        }
+    }
+    res.writeHead(statusCode, { 'Content-Type': 'application/json' });
+    res.end();
+}
+
+/**
+ * @param {http.IncomingMessage} req - http request object
+ * @param {http.ServerResponse} res - http response object
+ * @return {void}
+ */
+async function metricsHandler(req, res) {
+    if (req.method !== 'GET' || req.url !== '/metrics') {
+        return _writeResponse(res, errors.MethodNotAllowed);
+    }
+
+    try {
+        const promMetrics = await promClient.register.metrics();
+        const contentLen = Buffer.byteLength(promMetrics, 'utf8');
+        return res.writeHead(200, {
+            'content-length': contentLen,
+            'content-type': promClient.register.contentType,
+        }).end(promMetrics);
+    } catch (ex) {
+        return _writeResponse(res, errors.MethodNotAllowed);
+    }
+}
+
+module.exports = {
+    client: promClient,
+    collectDefaultMetrics,
+    metricsHandler,
+    bucketCount,
+};