Implement stats middleware removing some duplicated code

lib/cartodb/controllers/base.js

@@ -1,18 +1,13 @@
-var debug = require('debug')('windshaft:cartodb');
-
 function BaseController() {
 }
 
 module.exports = BaseController;
 
-// jshint maxcomplexity:9
 BaseController.prototype.send = function(req, res, body, status, headers) {
     if (req.params.dbhost) {
         res.set('X-Served-By-DB-Host', req.params.dbhost);
     }
 
-    res.set('X-Tiler-Profiler', req.profiler.toJSONString());
-
     if (headers) {
         res.set(headers);
     }
@@ -28,13 +23,4 @@ BaseController.prototype.send = function(req, res, body, status, headers) {
     } else {
         res.send(body);
     }
-
-    try {
-        // May throw due to dns, see
-        // See http://github.com/CartoDB/Windshaft/issues/166
-        req.profiler.sendStats();
-    } catch (err) {
-        debug("error sending profiling stats: " + err);
-    }
 };
-// jshint maxcomplexity:6

lib/cartodb/middleware/error-middleware.js

@@ -35,8 +35,6 @@ module.exports = function errorMiddleware (/* options */) {
             res.set('X-Served-By-DB-Host', res.locals.dbhost);
         }
 
-        res.set('X-Tiler-Profiler', req.profiler.toJSONString());
-
         res.status(statusCode);
 
         if (req.query && req.query.callback) {
@@ -44,14 +42,6 @@ module.exports = function errorMiddleware (/* options */) {
         } else {
             res.json(errorResponseBody);
         }
-
-        try {
-            // May throw due to dns, see
-            // See http://github.com/CartoDB/Windshaft/issues/166
-            req.profiler.sendStats();
-        } catch (err) {
-            debug("error sending profiling stats: " + err);
-        }
     };
 };
 

lib/cartodb/middleware/stats.js

@@ -0,0 +1,33 @@
+const Profiler = require('../stats/profiler_proxy');
+const debug = require('debug')('windshaft:cartodb:stats');
+const methods = ['send', 'json', 'jsonp'];
+
+module.exports = function statsMiddleware(options) {
+    const { enabled = true, statsClient } = options;
+
+    return function stats(req, res, next) {
+        req.profiler = new Profiler({
+            statsd_client: statsClient,
+            profile: enabled
+        });
+
+        methods.forEach((method) => {
+            const originalFn = res[method];
+
+            res[method] = function (body) {
+                res.set('X-Tiler-Profiler', req.profiler.toJSONString());
+
+                originalFn.call(this, body);
+
+                try {
+                    // May throw due to dns, see: http://github.com/CartoDB/Windshaft/issues/166
+                    req.profiler.sendStats();
+                } catch (err) {
+                    debug("error sending profiling stats: " + err);
+                }
+            };
+        });
+
+        next();
+    };
+};

lib/cartodb/server.js

@@ -12,7 +12,8 @@ var VarnishHttpCacheBackend = require('./cache/backend/varnish_http');
 var FastlyCacheBackend = require('./cache/backend/fastly');
 
 var StatsClient = require('./stats/client');
-var Profiler = require('./stats/profiler_proxy');
+const stats = require('./middleware/stats');
+
 var RendererStatsReporter = require('./stats/reporter/renderer');
 
 var windshaft = require('windshaft');
@@ -362,10 +363,6 @@ function bootstrap(opts) {
 
     app.use(function bootstrap$prepareRequestResponse(req, res, next) {
         req.context = req.context || {};
-        req.profiler = new Profiler({
-            statsd_client: global.statsClient,
-            profile: opts.useProfiler
-        });
 
         if (global.environment && global.environment.api_hostname) {
             res.set('X-Served-By-Host', global.environment.api_hostname);
@@ -374,6 +371,11 @@ function bootstrap(opts) {
         next();
     });
 
+    app.use(stats({
+        enabled: opts.useProfiler,
+        statsClient: global.statsClient
+    }));
+
     app.use(lzmaMiddleware);
 
     // temporary measure until we upgrade to newer version expressjs so we can check err.status