🔗 Out-of-the-box Elixir telemetry with Phoenix

Knowledge is power, and this is especially true for software. Telemetry puts software engineers in the driver's seat by exposing the underlying performance of a system. Identifying possible problems before they occur and proactively fixing them is better than waiting for users to point them out for you.

Telemetry refers to the instrumentation of a system. When you use your web application and take action, you emit events. These events can be aggregated to calculate statistics—which we call metrics—or written to logs. Later, they can be decorated with information that links them together.

This article will start by examining the built-in telemetry and metrics that come for free with the Phoenix framework in Elixir. Elixir is built on the BEAM virtual machine, which is cluster-friendly, so distributed telemetry works out of the box.