| # Cobalt |
| |
| [TOC] |
| |
| ## Summary |
| Cobalt is a system for collecting metrics from Fuchsia devices, sending |
| metric observations to servers running in the cloud, aggregating and analyzing |
| the collected observations and generating useful reports and visualizations. |
| Cobalt emphasizes the preservation of user privacy while collecting |
| high-quality, useful analytics. |
| |
| ## Concepts |
| |
| * **Customer** and **Project**. Cobalt is a multi-tenant system. We partition |
| the system using the notions of customer and project. For example |
| **Fuchsia** is a customer and **Ledger** is a project. |
| * **Metric**: A variable to be measured, e.g. the number of times that a Fuchsia |
| device was booted. |
| * **Observation**: A single measurement of a metric, e.g. |
| “This Fuchsia device has booted.” Observations are the units of data |
| transmitted from the client running Fuchsia to the Cobalt servers. |
| * **Encoding**: A built-in algorithm for encoding Observations. Some of Cobalt's |
| encodings implement special privacy-preserving algorithms. |
| |
| ## FIDL Protocol |
| Fuchsia code uses Cobalt through its FIDL protocol. |
| See [`//sdk/fidl/fuchsia.cobalt/cobalt.fidl`](/sdk/fidl/fuchsia.cobalt/cobalt.fidl). |
| |
| ### Cobalt Test App |
| |
| The Cobalt test app `cobalt_testapp.cc` serves as an example usage of the Cobalt |
| FIDL service. |
| |
| ### Building the test app: |
| |
| For example: |
| |
| ``` |
| $ fx set x64 |
| $ fx full-build |
| ``` |
| |
| ### Running the test app: |
| |
| Start Fuchsia. For example: |
| |
| ``` |
| $ fx emu -N |
| ``` |
| |
| From within Fuchsia: |
| |
| ``` |
| $ system/test/cobalt_testapp |
| ``` |
| or try |
| |
| ``` |
| $ system/test/cobalt_testapp --verbose=3 |
| ``` |
