fune/toolkit/components/glean/docs/code_organization.md

FOG code organization

.. notnote::

    Project FOG is currently being designed and implemented.
    This documentation is incomplete and may change significantly before FOG is usable inside mozilla-central.

The diagram shows the different modules of Project FOG.

FOG control

This module is the glue between Firefox and Glean.

• The code lives in toolkit/components/glean/src.
• It is written in Rust.
• The crate is named fog.
• It is not published to crates.io.
• It is not consumed by other Rust crates inside mozilla-central.

This module is responsible for

• collecting and assembling the client information
• configuring Glean
• watching the Firefox Telemetry data upload preference (datareporting.healthreport.uploadEnabled)
• scheduling builtin pings
• controling ping upload workers

It calls into glean_core to:

• configure and initialize Glean
• toggle upload_enabled
• get upload tasks

FOG API

This module provides the user-facing API for Glean inside mozilla-central.

• The code lives in toolkit/components/glean/api.
• It is written in Rust.
• The crate is named glean.
• It is not published to crates.io.
• It can be consumed by other Rust crates inside mozilla-central for their Glean usage.
• It will provide a build task for glean_parser integration.

This module is responsible for

• exposing a specific metric API in Rust
• wrapping metric implementations for handling IPC
• exposing FFI functionality to implement other language APIs on top

It calls into glean_core for:

• metric types (including pings)
• querying upload_enabled status.