Extension:EventLogging

The EventLogging extension makes it possible to collect structured data on how users interact with MediaWiki sites.

Features

 * EventLogging supports client-side logging from JavaScript and server-side logging from PHP.


 * The events are JSON objects defined by JSON schemas that can be edited on a MediaWiki server in a Schema: namespace; the latter feature is generally useful for storing other structured data in wiki pages.


 * The extension does not include any back-end code for transporting, parsing, or loading these events. A separate repository, [https://gerrit.wikimedia.org/r/#/admin/projects/eventlogging Eventlogging server], implements this functionality and deals with inserting into Kafka streams, SQL tables (automatically generated from the same schemas), and MongoDB collections.  The details of these components are specific to Wikimedia Foundation's configuration.

EventLogging at Wikimedia
The Wikimedia Foundation uses the EventLogging extension as part of a broader system for collecting, aggregating, storing, and analyzing user data within the limits set out by our privacy policy and data retention guidelines.

This page is about general use of the EventLogging extension. The Wikimedia Foundation uses EventLogging with WMF specific backend components and schema repositories. Much of the documentation here refers to unmaintained legacy features of EventLogging. For Wikimedia specific and maintained documentation, see Analytics/Systems/EventLogging and Event Platform.

Configuring the schema location
By default, the extension will look for schemas on Meta-Wiki. The relevant default settings are:

To use local schemas, or schemas from the central wiki of your own wikifarm, you need to override these. E.g. to use the  namespace of the local wiki, set

(and ensure the user account that will create the schemas is autoconfirmed).

Logging events using EventLogging

 * - to developing and deploying EventLogging schemas, and more
 * - tips and suggestions for developers writing code to log events

Tips
Read to learn about creating and using a proper schema for your event.

Don't use a schema name like "MyFakeTest" during development. Since schemas are referenced by MediaWiki revision ID, development versions won't conflict with production, so you should always use a real name and can point to the production wiki holding schemas during development.

Your code that logs events can fail if EventLogging is not available, or it can have a soft dependency.


 * Sample code for specifying a soft dependency on EventLogging.

Developer setup
As a developer, you will want to set up and use EventLogging on your development wiki to simulate its use in production.

Sanity checking your setup
Your local development wiki must be running some cache server, such as memcached.

describes the EventLogging configuration variables.

If not using MediaWiki-Vagrant, you will need to clone eventlogging server repository for local development.

So you can set

and run export PYTHONPATH=./server && server/bin/eventlogging-devserver in a terminal to see events. The MediaWiki-Vagrant server "appliance" uses port 8080, so you may want to use another port like 8081 for event.gif requests.

To verify your setup, browse to any page of your wiki, and in a JavaScript console enter

The last line will generate console warnings in debug mode as null is not a known schema, but eventlogging-devserver should dump the event along with its own warnings.

For server-side events, set  to a local file writable by the PHP/Web server, and in a terminal run tail -f on that file. This will dump any calls to the PHP  function.

Using mediawiki-vagrant
If you develop using mediawiki-vagrant, all of the above is encapsulated in the  role. To enable it, run:

And once in vagrant please take a look at Extension:EventLogging/Guide#Installing_the_eventlogging-devserver to see how to run the eventlogging devserver

For JavaScript development
If working on the javascript client, you'll need to install dependencies with  from the folder you're developing in. Then you can use  to lint for example. The "How to run tests" section below points out how to see JavaScript test results.

How to run tests
There are PHP tests, python tests, and JavaScript tests.

To run JavaScript tests, visit Special:JavaScriptTest/qunit on your development wiki. (see: Manual:JavaScript unit testing)

To run PHP tests, we use PHPUnit. Make sure it is installed, see: Manual:PHP unit testing/Installing PHPUnit). Then

To run eventlogging server python tests in vagrant you need to install tox. If you use Windows, may also need to clone it to a directory that is not shared between guest and host (to work around an apparent VirtualBox shared folder issue). For example:

Then, run tox:

Note that tox tries to run tests for Python 2.7 and Python 3.4. EventLogging runs with Python 2.7 in production. If you want to install Python 3 in Vagrant, run: