Internals

Here is a quick overview of the most important code parts. They can be found in the telemetry folder.

• TelemetryController: Main telemetry logic, e.g. assembling pings, local storage (when archiving is enabled), preference changes, testing

• Telemetry.cpp contains most of the public interface, implements the IDL

• The different data types for telemetry are handled in TelemetryHistogram, TelemetryScalar, TelemetryEvent.

• TelemetryEnvironment: A helper for gathering environment data, like build version or graphics data

• TelemetryScheduler: Starts regular jobs for collecting and sending data

• TelemetrySend: Sending and caching of pings

• TelemetryStorage: Handles writing pings to disk for TelemetrySend

• TelemetrySession: Collects data for a browsing session, includes many of the most important probes (aka metrics)

• Policy: A layer of indirection added to provide testability. A common pattern in many files

• pings/: Contains definitions and handling for most ping types, like EventPing

More details on different topics can be found in these chapters:

• Integration Tests
• Template for Mentored Bugs
• Ping Sender
• Preferences and Defines
• Telemetry review guidelines
• Tests