Extract profiler setup to its middleware

app/controllers/api-router.js

@@ -20,9 +20,12 @@ const JobController = require('./job_controller');
 const cors = require('../middlewares/cors');
 const servedByHostHeader = require('../middlewares/served-by-host-header');
 const logger = require('../middlewares/logger');
+const profiler = require('../middlewares/profiler');
 
 module.exports = class ApiRouter {
     constructor ({ redisPool, metadataBackend, statsClient, dataIngestionLogger }) {
+        this.statsClient = statsClient;
+
         const userLimitsServiceOptions = {
             limits: {
                 rateLimitsEnabled: global.settings.ratelimits.rateLimitsEnabled
@@ -66,6 +69,7 @@ module.exports = class ApiRouter {
         const apiRouter = router({ mergeParams: true });
 
         apiRouter.use(logger());
+        apiRouter.use(profiler({ statsClient: this.statsClient }));
         apiRouter.use(cors());
         apiRouter.use(servedByHostHeader());
 

app/middlewares/profiler.js

@@ -1,5 +1,18 @@
 'use strict';
 
+const Profiler = require('../stats/profiler-proxy');
+
+module.exports = function profiler ({ statsClient }) {
+    return function profilerMiddleware (req, res, next) {
+        req.profiler = new Profiler({
+            profile: global.settings.useProfiler,
+            statsd_client: statsClient
+        });
+
+        next();
+    };
+};
+
 module.exports.initializeProfilerMiddleware = function initializeProfiler (label) {
     return function initializeProfilerMiddleware (req, res, next) {
         if (req.profiler) {

app/server.js

@@ -17,7 +17,6 @@
 //
 
 var express = require('express');
-var Profiler = require('./stats/profiler-proxy');
 var fs = require('fs');
 var mkdirp = require('mkdirp');
 
@@ -75,15 +74,9 @@ function App(statsClient) {
         mkdirp.sync(global.settings.tmpDir);
     }
 
-    // Use step-profiler
     app.use(function bootstrap$prepareRequestResponse(req, res, next) {
         res.locals = res.locals || {};
 
-        var profile = global.settings.useProfiler;
-        req.profiler = new Profiler({
-            profile: profile,
-            statsd_client: statsClient
-        });
         next();
     });