Currently there is no way to disable the metrics via the config file.

As soon as a valid metrics entry is added (https://www.dropwizard.io/en/stable/manual/configuration.html#metrics), the metrics will be enabled. The problem is, when testing on localhost, one may not want the metrics to be reported.

Proposal: add support for an enabled: true/false field, both at the metrics level and for each reporter. This can then be used together with environment variable interpolation. For example:

metrics:
  enabled: ${ENABLE_METRICS:-false}

will cause the metrics to be disabled, unless there's an ENABLE_METRICS=true environment variable set. On test and live environments this env var could be set to true.

If this is an useful idea, I could create a PR.