Every event minato emits, in one module.

Instrumentation belongs in one place for the same reason the protocol codec does: the event names, the measurements and the metadata keys are a contract with whoever is collecting them, and a contract spread across eight call sites drifts. Everything here is telemetry, which is what an OpenTelemetry bridge, a Prometheus exporter and a logger handler all already know how to read.

The events

Spans follow the telemetry:span/3 shape, so each is three events - start, stop, and exception when the work raised - and stop carries a duration in native units.

What is in the metadata, and what is never

sql is present when minato was configured with log_statements => true, and absent otherwise. A statement is not a secret but it is close to one: SELECT * FROM users WHERE email = $1 in a log is fine, and the same statement written by a caller that pasted the value in is a leak. Parameters are never in an event, in any configuration, for the same reason - they are the values themselves.

Passwords never reach this module at all. See minato_conn for where they stop.

Attaching

telemetry:attach(<<"minato-slow">>, [minato, query, stop], fun
    (_Event, #{duration := Duration}, #{command := Command}, _Config) ->
        case erlang:convert_time_unit(Duration, native, millisecond) of
            Slow when Slow > 100 -> logger:warning(#{slow_query => Command, ms => Slow});
            _Fast -> ok
        end
end, undefined).