Dropwizard healthchecks based on logged errors

Service.java

    @Override
    public void doRun(SwitchboardConfiguration configuration, Environment environment) throws Exception {

        Optional<Meter> allLogs = Optional.fromNullable( environment.metrics().getMeters().get("ch.qos.logback.core.Appender.all") );
        Optional<Meter> warnLogs = Optional.fromNullable( environment.metrics().getMeters().get("ch.qos.logback.core.Appender.warn") );
        Optional<Meter> errorLogs = Optional.fromNullable( environment.metrics().getMeters().get("ch.qos.logback.core.Appender.error") );
        if(allLogs.isPresent()) {
            if(errorLogs.isPresent()) registerLogMeterAsHealthCheck(environment, allLogs.get(), errorLogs.get(), "logged_errors", 0.05D);
            if(warnLogs.isPresent()) registerLogMeterAsHealthCheck(environment, allLogs.get(), warnLogs.get(), "logged_warns", 0.25D);
        }
    }


    /**
     * Registers logged event meters as a health check by comparing the five minute rates for all logs versus the supplied metric
     * @param environment yup
     * @param allMeter meter for all logs
     * @param meter meter for error or warn logs (recommended)
     * @param name name of healthcheck
     * @param threshold is inclusive
     */
    private void registerLogMeterAsHealthCheck(Environment environment, Meter allMeter, Meter meter, String name, Double threshold) {
        environment.healthChecks().register(name, new HealthCheck() {
            @Override protected Result check() throws Exception {
                Double ratio = (meter.getFiveMinuteRate() / Double.max(allMeter.getFiveMinuteRate(), Double.MIN_VALUE)) * 100.0D;
                String message = ratio + "%";
                if(ratio >= threshold) return HealthCheck.Result.unhealthy(message);
                else return HealthCheck.Result.healthy(message);
            }
        });
    }