# Logger
URL: /logger

Explore how to configure logger options in OpenHTF to capture and manage log output during test execution with examples.

Capture structured log output during test execution.

Logging is crucial for debugging and tracking test execution. OpenHTF offers a logger that captures detailed outputs, custom messages, and error traces, which are saved to test records through output callbacks.

You can log events in phases and plugs with four different levels depending on the severity: `debug` for detailed troubleshooting, `info` for general information, `warning` for potential issues, and `error` for failures.

You can print the logs to the console, using the `-v` flag to control verbosity. All flags are listed on the command-line reference.

Default: No logs are printed.

`-v`: Logs at the `info` level and above are printed.

`-vv`: Logs at the `debug` level and above are printed.

All logs are saved to the report file via output callbacks if enabled.

You can use the logger extended features for advanced use cases.

OpenHTF organizes its loggers hierarchically, with different categories managing parts of the framework and test executions.

**Framework logs**: Manage internal logs for core OpenHTF operations (e.g. `openhtf.core.test_descriptor`, `openhtf.util.threads`).

**Test record logs**: Specific to each test, prefixed by `openhtf.test_record.<test_uid>`, capturing test details.

**Test subsystem logs**: Handle logs for individual test phases and plugs, identified by `openhtf.test_record.<test_uid>.phase.<phase_name>` or `openhtf.test_record.<test_uid>.plug.<plug_name>`.

You can customize the logger format.

Sample output:

<Card title="Output Callbacks" href="/output-callbacks" description="Where log records end up: JSON files or custom sinks." />

<Card title="Test Record" href="/test-record" description="The log_records field and the rest of the record." />

<Card title="Plugs" href="/plugs" description="Plugs log through self.logger, shown above." />