Adding service level objectives support to the @timed annotation

Author: lcavadas

micrometer-core/src/main/java/io/micrometer/core/annotation/Timed.java

@@ -74,6 +74,15 @@
      */
     boolean histogram() default false;
 
+    /**
+     * List of service level objectives to calculate client-side for the
+     * {@link io.micrometer.core.instrument.Timer} in seconds. For example, for a 100ms
+     * should be passed as {@code 0.1}.
+     * @return service level objectives to calculate
+     * @see io.micrometer.core.instrument.Timer.Builder#serviceLevelObjectives(java.time.Duration...)
+     */
+    double[] serviceLevelObjectives() default {};
+
     /**
      * Description of the {@link io.micrometer.core.instrument.Timer}.
      * @return meter description

micrometer-core/src/main/java/io/micrometer/core/aop/TimedAspect.java

@@ -20,14 +20,18 @@
 import io.micrometer.core.annotation.Incubating;
 import io.micrometer.core.annotation.Timed;
 import io.micrometer.core.instrument.*;
+import io.micrometer.core.instrument.util.TimeUtils;
 import org.aspectj.lang.ProceedingJoinPoint;
 import org.aspectj.lang.annotation.Around;
 import org.aspectj.lang.annotation.Aspect;
 import org.aspectj.lang.reflect.MethodSignature;
 
 import java.lang.reflect.Method;
+import java.time.Duration;
+import java.util.Arrays;
 import java.util.Optional;
 import java.util.concurrent.CompletionStage;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 import java.util.function.Predicate;
 
@@ -254,7 +258,10 @@ private Timer.Builder recordBuilder(ProceedingJoinPoint pjp, Timed timed, String
             .tags(EXCEPTION_TAG, exceptionClass)
             .tags(tagsBasedOnJoinPoint.apply(pjp))
             .publishPercentileHistogram(timed.histogram())
-            .publishPercentiles(timed.percentiles().length == 0 ? null : timed.percentiles());
+            .serviceLevelObjectives((Duration[]) Arrays.stream(timed.serviceLevelObjectives())
+                .mapToObj(s -> Duration.ofNanos((long) TimeUtils.secondsToUnit(s, TimeUnit.NANOSECONDS)))
+                .toArray());
+
         if (meterTagAnnotationHandler != null) {
             meterTagAnnotationHandler.addAnnotatedParameters(builder, pjp);
         }

micrometer-core/src/main/java/io/micrometer/core/instrument/Timer.java

@@ -22,9 +22,12 @@
 import io.micrometer.core.instrument.distribution.HistogramSupport;
 import io.micrometer.core.instrument.distribution.ValueAtPercentile;
 import io.micrometer.core.instrument.distribution.pause.PauseDetector;
+import io.micrometer.core.instrument.util.TimeUtils;
 
 import java.time.Duration;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.concurrent.Callable;
 import java.util.concurrent.TimeUnit;
 import java.util.function.*;
@@ -100,7 +103,10 @@ static Builder builder(Timed timed, String defaultName) {
         return new Builder(timed.value().isEmpty() ? defaultName : timed.value()).tags(timed.extraTags())
             .description(timed.description().isEmpty() ? null : timed.description())
             .publishPercentileHistogram(timed.histogram())
-            .publishPercentiles(timed.percentiles().length > 0 ? timed.percentiles() : null);
+            .publishPercentiles(timed.percentiles().length > 0 ? timed.percentiles() : null)
+            .serviceLevelObjectives((Duration[]) Arrays.stream(timed.serviceLevelObjectives())
+                .mapToObj(s -> Duration.ofNanos((long) TimeUtils.secondsToUnit(s, TimeUnit.NANOSECONDS)))
+                .toArray());
     }
 
     /**