This library uses sensors of Faust. Those sensors are events based. Our monitor implements that interface and hooks some actions when those events happen. That allows us to create our own prometheus Counters, Gauges and Histograms. I created some predefined metrics, but we can expand on them in the future.

To use this library in your faust project just add faust-prometheus or install it through pip:

pip install faust-prometheus

Add PrometheusMonitor to the app as seen below:

    import faust
    from faustprometheus.monitor import PrometheusMonitor

    app = faust.App('example', broker='kafka://')
    app.monitor = PrometheusMonitor(app)

You can also configure some global options to monitor through PrometheusMonitorConfig, such as 2 levels of prefixes, through namespace and subsystem. The path exposing prometheus metrics can be set through metrics config, with /metrics as default value. I added labels to config, but are not applied to monitor due to lack of my understanding of faust sensors and prometheus.

    from faustprometheus.config import PrometheusMonitorConfig

    monitor_config = PrometheusMonitorConfig(
        path='/metrics',
        namespace='faust',
        subsystem='foo-app',
        labels=['v2.3', 'prod']
        )        

Library is fully unit tested and can be run by

    pytest