From 70a38a045723cc98fefe9016ed5da3725d730a74 Mon Sep 17 00:00:00 2001
From: Maxime Rainville <maxime@silverstripe.com>
Date: Thu, 17 Jan 2019 16:30:00 +1300
Subject: [PATCH] NEW Add new execmetric debur URL parameter to print out
 exection time and peak memory usage

---
 .../07_Debugging/02_URL_Variable_Tools.md     |  3 +-
 src/Control/HTTPApplication.php               | 50 +++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/docs/en/02_Developer_Guides/07_Debugging/02_URL_Variable_Tools.md b/docs/en/02_Developer_Guides/07_Debugging/02_URL_Variable_Tools.md
index 3217c114d84..e8ae2cbcc37 100644
--- a/docs/en/02_Developer_Guides/07_Debugging/02_URL_Variable_Tools.md
+++ b/docs/en/02_Developer_Guides/07_Debugging/02_URL_Variable_Tools.md
@@ -28,7 +28,8 @@ session variables, used templates and much more.
  | isDev         | | 1      | | Put the site into [development mode](../), enabling debugging messages to the browser on a live server.  For security, you'll be asked to log in with an administrator log-in. Will persist for the current browser session. | 
  | isTest        | | 1      | | See above. | 
  | debug         | | 1      | | Show a collection of debugging information about the director / controller operation        |
- | debug_request | | 1      | | Show all steps of the request from initial [HTTPRequest](api:SilverStripe\Control\HTTPRequest) to [Controller](api:SilverStripe\Control\Controller) to Template Rendering  | 
+ | debug_request | | 1      | | Show all steps of the request from initial [HTTPRequest](api:SilverStripe\Control\HTTPRequest) to [Controller](api:SilverStripe\Control\Controller) to Template Rendering  |
+ | execmetric    | | 1      | | Dispaly the execution time and peak memory usage for the request |  
 
 ## Classes and Objects
 
diff --git a/src/Control/HTTPApplication.php b/src/Control/HTTPApplication.php
index 35f453d6da4..017a6941085 100644
--- a/src/Control/HTTPApplication.php
+++ b/src/Control/HTTPApplication.php
@@ -5,6 +5,7 @@
 use SilverStripe\Control\Middleware\HTTPMiddlewareAware;
 use SilverStripe\Core\Application;
 use SilverStripe\Core\Kernel;
+use SilverStripe\Dev\Debug;
 
 /**
  * Invokes the HTTP application within an ErrorControlChain
@@ -18,6 +19,8 @@ class HTTPApplication implements Application
      */
     protected $kernel;
 
+    protected $showExecMetric = false;
+
     public function __construct(Kernel $kernel)
     {
         $this->kernel = $kernel;
@@ -42,6 +45,7 @@ public function getKernel()
     public function handle(HTTPRequest $request)
     {
         $flush = array_key_exists('flush', $request->getVars()) || ($request->getURL() === 'dev/build');
+        $this->showExecMetric = Director::isDev() && array_key_exists('execmetric', $request->getVars());
 
         // Ensure boot is invoked
         return $this->execute($request, function (HTTPRequest $request) {
@@ -59,6 +63,8 @@ public function handle(HTTPRequest $request)
      */
     public function execute(HTTPRequest $request, callable $callback, $flush = false)
     {
+        $start = microtime(true);
+
         try {
             return $this->callMiddleware($request, function ($request) use ($callback, $flush) {
                 // Pre-request boot
@@ -69,6 +75,50 @@ public function execute(HTTPRequest $request, callable $callback, $flush = false
             return $ex->getResponse();
         } finally {
             $this->getKernel()->shutdown();
+
+            if ($this->showExecMetric) {
+                $end = microtime(true);
+                Debug::message(
+                    sprintf(
+                        "Execution time: %s, Peak memory usage: %s\n",
+                        $this->formatExecutionTime($start, $end),
+                        $this->formatPeakMemoryUsage()
+                    ),
+                    false
+                );
+            }
         }
     }
+
+    /**
+     * Convert the provided start and end time to a interval in secs.
+     * @param float $start
+     * @param float $end
+     * @return string
+     */
+    protected function formatExecutionTime($start, $end)
+    {
+        $diff = round($end - $start, 4);
+        return $diff . ' seconds';
+    }
+
+    /**
+     * Get the peak memory usage formatted has a string and a meaningful unit.
+     * @return string
+     */
+    protected function formatPeakMemoryUsage()
+    {
+        $bytes = memory_get_peak_usage(true);
+        $precision = 2;
+
+        $units = array('B', 'KB', 'MB', 'GB', 'TB');
+
+        $bytes = max($bytes, 0);
+        $pow = floor(($bytes ? log($bytes) : 0) / log(1024));
+        $pow = min($pow, count($units) - 1);
+
+         $bytes /= pow(1024, $pow);
+
+        return round($bytes, $precision) . ' ' . $units[$pow];
+    }
 }