Manual call alternative for grails.plugin.dropwizard.metrics.timers.@timed for Grails 3

readme.txt

Class `MetricsMethodUtilsService` helps to manually call DropWizard metrics with custom class

example.groovy

class DemoController() {
    MetricsMethodUtilsService metricsMethodUtilsService 
  
    def index() {
        render metricsMethodUtilsService.start(getClass(), "index", {
                "Hello World"
        })
    }  
}

MetricsMethodUtilsService.groovy

import com.codahale.metrics.MetricRegistry
import com.codahale.metrics.Timer
import groovy.transform.stc.ClosureParams
import groovy.transform.stc.FirstParam
import groovy.util.logging.Log4j

@Log4j
class MetricsMethodUtilsService {
    MetricRegistry metricRegistry

    private static LinkedHashMap<String, Timer> metricsContexts = []

    private Timer getTimerContext(Class clazz, String metricName) {
        String contextKey = createContextKey(clazz, metricName)

        Timer context = metricsContexts.get(contextKey)

        if(!context) {
            context = createContext(clazz, metricName)

            metricsContexts.put(contextKey, context)
        }

        context
    }

    private Timer createContext(Class clazz, String metricName) {
       metricRegistry.timer(MetricRegistry.name(clazz, metricName))
    }

    private String createContextKey(Class clazz, String metricName) {
        clazz.name + "." + metricName
    }

    /**
     * Call a passes Closure function. Function returns a closure response
     *
     * @param clazz
     * @param metricName
     * @param body
     * @return
     */
    def start(Class clazz, String metricName, @ClosureParams(FirstParam.FirstGenericType.class) Closure body) {
        Timer.Context context = getTimerContext(clazz, metricName).time()

        if(!context) {
            log.warn("Not found TimerContext for $clazz.$metricName")

            return body.call()
        }

        try {
            return body.call()
        } finally {
            context.stop()
        }
    }
}