observability.md

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3	Observability

Observability

Logging

The log level and format can be adjusted by configuration flags.

Please note that the structured log format is not stable yet; field names and formatting of values might change in minor releases.

Docker logs

If Docker was launched with our quick local setup with Docker Compose, the following command can be used to fetch the logs.

docker compose logs ferretdb

Otherwise, you can check a list of running Docker containers with docker ps and get logs with docker logs:

$ docker ps
CONTAINER ID   IMAGE                       COMMAND                  CREATED              STATUS          PORTS                                           NAMES
13db4c8800d3   postgres                    "docker-entrypoint.s…"   About a minute ago   Up 59 seconds   5432/tcp                                        my-postgres
44fe6f4c3527   ghcr.io/ferretdb/ferretdb   "/ferretdb"              About a minute ago   Up 59 seconds   8080/tcp, 27018/tcp, 0.0.0.0:27017->27017/tcp   my-ferretdb

$ docker logs my-ferretdb

Binary executable logs

FerretDB writes logs to the standard error (stderr) stream.

Metrics

FerretDB exposes metrics in Prometheus format on the debug handler on http://127.0.0.1:8088/debug/metrics by default. There is no need to use an external exporter. The host and port can be changed with --debug-addr flag.

Please note that the set of metrics is not stable yet; metric and label names and formatting of values might change in minor releases.