The live data console
In order to aid debugging and monitoring of the application, a specific "live view" API and UI page is provided on each backend instance. It provides an instant view of what is happening on the tracker.
The live data console is available on the /internal/live.html URL.
The top of the console displays throughput data
The input section displays:
- The number of tracking requests received (either through the Javascript tracking or API tracking), since this instance of the WT1 server last restarted
- The current throughput in events per second.
The storage of WT1 events is done by an asynchronous processing queue. For more information, please see the Architecture page.
If the queue gets full during processing of events, some events can be dropped. They appear in the "events lost in queue" counter. Successfully queued events appear in "events queued".
The storage engine queue receives the events, and periodically stores them:
- "events processed" indicates how many events have been actually processed by the background storage queue
- "events saved" indicates how many events were successfully synced to stable storage The second line stores details about the storage files.
The Flush button triggers a flush of the event queue.
There is one line for each event handler. See Event handlers for more information.
The counters are the same as the storage ones.
The bottom of the console displays the last 100 requests received by the tracker. For each request, all available info is printed.
This is especially useful for developers, to check that all data that they intend to track is indeed received and recorded by the tracker.
The live data console is powered by a JSON REST API, available on /internal/live
It provides:
- All details of the last 100 received requests
- Number of tracking events received since backend startup
- Number of tracking events lost since backend startup (because a queue was full)
- Number of tracking events enqueued since backend startup
- Number of tracking events processed by the queue since backend startup
- Number of tracking events saved to disk since backend startup
- Number of files created since backend startup
- Total size of written files and received data since backend startup