Configure logging

By default, the Flower logger uses logging level INFO. This can be changed via the PYTHONLOGLEVEL environment variable to any other levels that Python’s logging module supports. For example, to launch your SuperLink showing DEBUG logs do:

# Launch the SuperLink with TLS (or use --insecure)
PYTHONLOGLEVEL=DEBUG flower-superlink \
    --ssl-ca-certfile certificates/ca.crt \
    --ssl-certfile certificates/server.pem \
    --ssl-keyfile certificates/server.key

INFO 2025-01-27 11:46:41,690:      Starting Flower SuperLink
INFO 2025-01-27 11:46:41,697:      Flower Deployment Engine: Starting Exec API on 0.0.0.0:9093
INFO 2025-01-27 11:46:41,724:      Flower ECE: Starting ServerAppIo API (gRPC-rere) on 0.0.0.0:9091
INFO 2025-01-27 11:46:41,728:      Flower ECE: Starting Fleet API (gRPC-rere) on 0.0.0.0:9092
DEBUG 2025-01-27 11:46:41,730:     Started flwr-serverapp scheduler thread.
DEBUG 2025-01-27 11:46:41,730:     Using InMemoryState

Note

You can make use of the PYTHONLOGLEVEL environment variable when executing other Flower commands to provision the different components in a Flower Federation (see Run Flower with the Deployment Engine) or using the flwr CLI.