Magento OpenCensus

Project Outline

This is the Magento 2 opencensus project. It integrates these two projects together:

• Magento 2: An open source e-commerce platform
• OpenCensus: An implementation of Transaction Tracing

Similar Work

• The author knows of some work to integrate the profiler with flame graphs.

Justification

Transaction Traces allow getting complex performance data from an application in an easy to navigate format.

Installation

This requires an additional patch to the bootstrap file. This has been submitted as a pull request against Magento 2, but is included below for illustrative purposes:

diff --git a/app/bootstrap.php b/app/bootstrap.php
index e77c6d432c8..b3f2c71f0f8 100644
--- a/app/bootstrap.php
+++ b/app/bootstrap.php
@@ -54,12 +54,18 @@ if (
     && isset($_SERVER['HTTP_ACCEPT'])
     && strpos($_SERVER['HTTP_ACCEPT'], 'text/html') !== false
 ) {
-    $profilerFlag = isset($_SERVER['MAGE_PROFILER']) && strlen($_SERVER['MAGE_PROFILER'])
+    $profilerString = isset($_SERVER['MAGE_PROFILER']) && strlen($_SERVER['MAGE_PROFILER'])
         ? $_SERVER['MAGE_PROFILER']
         : trim(file_get_contents(BP . '/var/profiler.flag'));

-    \Magento\Framework\Profiler::applyConfig(
-        $profilerFlag,
+    if ($profilerString && $profilerArray = json_decode($profilerString, true)) {
+        $profilerConfig = $profilerArray;
+    } else {
+        $profilerConfig = $profilerString;
+    }
+
+    Magento\Framework\Profiler::applyConfig(
+        $profilerConfig,
         BP,
         !empty($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest'
     );

See https://github.com/magento/magento2/pull/15171 for details. More generally, this allows injecting complex configuration to the bootstrap process. It might not be 100% secure -- use with caution.

Once the patch above is applied, it's possible to configure the profiler.

Configuration

The $profilerConfig array expects something along the following lines:

    $profilerConfig = [
        'drivers' => [
                [

                // The type of profiling driver that will be run
                'type' => 'Sitewards\OpenCensus\Profiler\Driver\OpenCensus',

                // driver specific configuration configuration
                'exporter' => [

                    // The type of exporter that will be loaded
                    'type' => '\OpenCensus\Trace\Exporter\ZipkinExporter',

                    // An *ORDERED ARRAY* of arguments that will be unpacked with the `...` into the exporter
                    // constructor
                    'args' => [
                        'magento2',
                        'http://jaeger-host:9411/api/v2/spans'
                    ]
                ]
            ]
        ]
    ];

Expressed as JSON, this looks something like:

{"drivers":[{"type":"Sitewards\\OpenCensus\\Profiler\\Driver\\OpenCensus","exporter":{"type":"\\OpenCensus\\Trace\\Exporter\\ZipkinExporter","args":["magento2","http:\/\/jaeger-host:9411\/api\/v2\/spans"]}}]}

This will configure the Zipkin exporter to a Jaeger host. Due to a particular quirk associated with how UDP is handled (specifically, max packet size being too large) this seems the most reliable configuration with the nicest UI.

Usage:

Probably don't. It's still very experimental.

Thanks

• David Manners
• The Commwrap Team