仅当 Prometheus 指标不存在时才在 Python 中注册它

Question

I'm making use of the multiprocess prometheus collector (in python), but likely this problem would exist for single process as well.

Is there a way to check if a Counter Metric already exists, to prevent the attempt of registering a duplicate ? Multiple calls to the below code generate the appended error. Or alternatively to check if a given metric exists, and get it.

Some kind of look up in the Registry ? The docs seems rather lacking.

Code:

logging_counter = prometheus_client.Counter('test', 'test')

Error generated:

ValueError: Duplicated timeseries in CollectorRegistry: {'test', 'test_total', 'test_created'}

Answer 1

Ended up being an issue with how MultiProcessCollector was setup ... make sure that at the subprocess level you initialize with CollectorRegistry and not Registry.

Proper Solution:

prometheus_client.multiprocess.MultiProcessCollector(prometheus_client.registry.REGISTRY)

Incorrect Solution:

prometheus_client.multiprocess.MultiProcessCollector(CollectorRegistry())