event-timings.md

Appium Event Timing

Appium comes with the ability to retrieve timing information about startup information and command length. This is an advanced feature that is controlled by the use of the eventTimings capability (set it to true to log event timings).

With this capability turned on, the GET /session/:id response (i.e., the response to driver.getSessionDetails() or similar, depending on client) will be decorated with an events property. This is the structure of that events property:

{
    "<event_type>": [<occurence_timestamp_1>, ...],
    "commands": [
        {
            "cmd": "<command_name>",
            "startTime": <js_timestamp>,
            "endTime": <js_timestamp>
        },
        ...
    ]
}

In other words, the events property has 2 kinds of properties of its own:

• Properties which are the names of event types
• The commands property

Properties which are names of event types correspond to an array of timestamps when that event happened. It's an array because events might happen multiple times in the course of a session. Examples of event types include:

• newSessionRequested
• newSessionStarted

(Individual drivers will define their own event types, so we do not have an exhaustive list to share here. It's best to actually get one of these responses from a real session to inspect the possible event types.)

The commands property is an array of objects. Each object has the name of the Appium-internal command (for example click), as well as the time the command started processing and the time it finished processing.

With this data, you can calculate the time between events, or a strict timeline of events, or statistical information about average length of a certain type of command, and so on.

You can only receive data about events that have happened when you make the call to /session/:id, so the best time to get data about an entire session is right before quitting it.

The Appium team maintains an event timings parser tool that can be used to generate various kinds of reports from event timings output: appium/appium-event-parser.

Add a custom event

Since Appium 1.16.0, you can add a custom event. You can send a custom event name to the Appium server using the Log Event API, and the server will store the timestamp. The Get events command can be used to retrieve named events' timestamps later on.