Scale long task timers to the implementation's base time unit

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

@@ -19,6 +19,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.Callable;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
 
@@ -101,14 +102,15 @@ default void record(Runnable f) {
      * Returns the current duration for an active task.
      *
      * @param task Id for the task to stop. This should be the value returned from {@link #start()}.
+     * @param unit The time unit to scale the returned value to.
      * @return Duration for the task in nanoseconds. A -1 value will be returned for an unknown task.
      */
-    long duration(long task);
+    double duration(long task, TimeUnit unit);
 
     /**
      * Returns the cumulative duration of all current tasks in nanoseconds.
      */
-    long duration();
+    double duration(TimeUnit unit);
 
     /**
      * Returns the current number of tasks being executed.
@@ -119,7 +121,7 @@ default void record(Runnable f) {
     default Iterable<Measurement> measure() {
         return Arrays.asList(
             new Measurement(() -> (double) activeTasks(), Statistic.Count),
-            new Measurement(() -> (double) duration(), Statistic.Total)
+            new Measurement(() -> duration(TimeUnit.NANOSECONDS), Statistic.Total)
         );
     }
 

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

@@ -91,18 +91,11 @@ default Runnable wrap(Runnable f) {
      */
     double totalTime(TimeUnit unit);
 
-    /**
-     * The total time in nanoseconds of all recorded events since this timer was created.
-     */
-    default double totalTimeNanos() {
-        return totalTime(TimeUnit.NANOSECONDS);
-    }
-
     @Override
     default Iterable<Measurement> measure() {
         return Arrays.asList(
             new Measurement(() -> (double) count(), Statistic.Count),
-            new Measurement(this::totalTimeNanos, Statistic.Total)
+            new Measurement(() -> totalTime(TimeUnit.NANOSECONDS), Statistic.Total)
         );
     }
 

micrometer-core/src/main/java/io/micrometer/core/instrument/composite/CompositeLongTaskTimer.java

@@ -20,10 +20,12 @@
 import io.micrometer.core.instrument.Meter;
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.noop.NoopLongTaskTimer;
+import io.micrometer.core.instrument.util.TimeUtils;
 
 import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
 
 public class CompositeLongTaskTimer extends AbstractMeter implements LongTaskTimer, CompositeMeter {
     private final Map<MeterRegistry, LongTaskTimer> timers = Collections.synchronizedMap(new LinkedHashMap<>());
@@ -53,22 +55,22 @@ public long stop(long task) {
     }
 
     @Override
-    public long duration(long task) {
+    public double duration(long task, TimeUnit unit) {
         synchronized (timers) {
             return timers.values().stream()
-                .map(ltt -> ltt.duration(task))
+                .map(ltt -> ltt.duration(task, unit))
                 .reduce((t1, t2) -> t2 == -1 ? t1 : t2)
-                .orElse(NoopLongTaskTimer.INSTANCE.duration(task));
+                .orElse(NoopLongTaskTimer.INSTANCE.duration(task, unit));
         }
     }
 
     @Override
-    public long duration() {
+    public double duration(TimeUnit unit) {
         synchronized (timers) {
             return timers.values().stream()
-                .map(LongTaskTimer::duration)
+                .map(ltt -> ltt.duration(unit))
                 .reduce((t1, t2) -> t2)
-                .orElse(NoopLongTaskTimer.INSTANCE.duration());
+                .orElse(NoopLongTaskTimer.INSTANCE.duration(unit));
         }
     }
 

micrometer-core/src/main/java/io/micrometer/core/instrument/dropwizard/DropwizardMeterRegistry.java

@@ -102,7 +102,7 @@ private Histogram<?> registerHistogramCounterIfNecessary(Meter.Id id, Histogram.
     protected LongTaskTimer newLongTaskTimer(Meter.Id id) {
         LongTaskTimer ltt = new SimpleLongTaskTimer(id, clock);
         registry.register(nameMapper.toHierarchicalName(id) + ".active", (Gauge<Integer>) ltt::activeTasks);
-        registry.register(nameMapper.toHierarchicalName(id) + ".duration", (Gauge<Long>) ltt::duration);
+        registry.register(nameMapper.toHierarchicalName(id) + ".duration", (Gauge<Double>) () -> ltt.duration(TimeUnit.NANOSECONDS));
         return ltt;
     }
 

micrometer-core/src/main/java/io/micrometer/core/instrument/noop/NoopLongTaskTimer.java

@@ -17,6 +17,8 @@
 
 import io.micrometer.core.instrument.LongTaskTimer;
 
+import java.util.concurrent.TimeUnit;
+
 public class NoopLongTaskTimer extends NoopMeter implements LongTaskTimer {
     public static NoopLongTaskTimer INSTANCE = new NoopLongTaskTimer();
 
@@ -33,12 +35,12 @@ public long stop(long task) {
     }
 
     @Override
-    public long duration(long task) {
+    public double duration(long task, TimeUnit unit) {
         return -1;
     }
 
     @Override
-    public long duration() {
+    public double duration(TimeUnit unit) {
         return 0;
     }
 

micrometer-core/src/main/java/io/micrometer/core/instrument/simple/SimpleLongTaskTimer.java

@@ -20,9 +20,11 @@
 import io.micrometer.core.instrument.LongTaskTimer;
 import io.micrometer.core.instrument.Meter;
 import io.micrometer.core.instrument.util.MeterEquivalence;
+import io.micrometer.core.instrument.util.TimeUtils;
 
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
 
 public class SimpleLongTaskTimer extends AbstractMeter implements LongTaskTimer {
@@ -54,19 +56,19 @@ public long stop(long task) {
     }
 
     @Override
-    public long duration(long task) {
+    public double duration(long task, TimeUnit unit) {
         Long startTime = tasks.get(task);
-        return (startTime != null) ? (clock.monotonicTime() - startTime) : -1L;
+        return (startTime != null) ? TimeUtils.nanosToUnit(clock.monotonicTime() - startTime, unit) : -1L;
     }
 
     @Override
-    public long duration() {
+    public double duration(TimeUnit unit) {
         long now = clock.monotonicTime();
         long sum = 0L;
         for (long startTime : tasks.values()) {
             sum += now - startTime;
         }
-        return sum;
+        return TimeUtils.nanosToUnit(sum, unit);
     }
 
     @Override

micrometer-core/src/main/java/io/micrometer/core/instrument/spectator/SpectatorLongTaskTimer.java

@@ -15,10 +15,15 @@
  */
 package io.micrometer.core.instrument.spectator;
 
+import ch.qos.logback.core.util.TimeUtil;
 import io.micrometer.core.instrument.AbstractMeter;
 import io.micrometer.core.instrument.LongTaskTimer;
 import io.micrometer.core.instrument.Meter;
 import io.micrometer.core.instrument.util.MeterEquivalence;
+import io.micrometer.core.instrument.util.TimeUtils;
+
+import java.sql.Time;
+import java.util.concurrent.TimeUnit;
 
 public class SpectatorLongTaskTimer extends AbstractMeter implements LongTaskTimer {
     private final com.netflix.spectator.api.LongTaskTimer timer;
@@ -39,13 +44,13 @@ public long stop(long task) {
     }
 
     @Override
-    public long duration(long task) {
-        return timer.duration(task);
+    public double duration(long task, TimeUnit unit) {
+        return TimeUtils.nanosToUnit(timer.duration(task), unit);
     }
 
     @Override
-    public long duration() {
-        return timer.duration();
+    public double duration(TimeUnit unit) {
+        return TimeUtils.nanosToUnit(timer.duration(), unit);
     }
 
     @Override

micrometer-core/src/test/java/io/micrometer/core/instrument/LongTaskTimerTest.java

@@ -19,6 +19,8 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ArgumentsSource;
 
+import java.util.concurrent.TimeUnit;
+
 import static io.micrometer.core.instrument.MockClock.clock;
 import static java.util.Collections.emptyList;
 import static org.junit.jupiter.api.Assertions.assertAll;
@@ -35,15 +37,17 @@ void record(MeterRegistry registry) {
         long tId = t.start();
         clock(registry).addAndGetNanos(10);
 
-        assertAll(() -> assertEquals(10, t.duration()),
-                () -> assertEquals(10, t.duration(tId)),
-                () -> assertEquals(1, t.activeTasks()));
+        assertAll(() -> assertEquals(10, t.duration(TimeUnit.NANOSECONDS)),
+            () -> assertEquals(0.01, t.duration(TimeUnit.MICROSECONDS)),
+            () -> assertEquals(10, t.duration(tId, TimeUnit.NANOSECONDS)),
+            () -> assertEquals(0.01, t.duration(tId, TimeUnit.MICROSECONDS)),
+            () -> assertEquals(1, t.activeTasks()));
 
         clock(registry).addAndGetNanos(10);
         t.stop(tId);
 
-        assertAll(() -> assertEquals(0, t.duration()),
-                () -> assertEquals(-1, t.duration(tId)),
-                () -> assertEquals(0, t.activeTasks()));
+        assertAll(() -> assertEquals(0, t.duration(TimeUnit.NANOSECONDS)),
+            () -> assertEquals(-1, t.duration(tId, TimeUnit.NANOSECONDS)),
+            () -> assertEquals(0, t.activeTasks()));
     }
 }

micrometer-core/src/test/java/io/micrometer/core/instrument/TimerTest.java

@@ -57,7 +57,7 @@ void recordNegative(MeterRegistry registry) {
         t.record(-42, TimeUnit.MILLISECONDS);
 
         assertAll(() -> assertEquals(0L, t.count()),
-                () -> assertEquals(0, t.totalTimeNanos(), 1.0e-12));
+                () -> assertEquals(0, t.totalTime(TimeUnit.NANOSECONDS), 1.0e-12));
     }
 
     @DisplayName("zero times contribute to the count of overall events but do not add to total time")
@@ -69,7 +69,7 @@ void recordZero(MeterRegistry registry) {
         clock(registry).addAndGet(1, TimeUnit.SECONDS);
 
         assertAll(() -> assertEquals(1L, t.count()),
-                () -> assertEquals(0L, t.totalTimeNanos()));
+                () -> assertEquals(0L, t.totalTime(TimeUnit.NANOSECONDS)));
     }
 
     @DisplayName("record a runnable task")
@@ -83,7 +83,7 @@ void recordWithRunnable(MeterRegistry registry) throws Exception {
             clock(registry).addAndGet(1, TimeUnit.SECONDS);
         } finally {
             assertAll(() -> assertEquals(1L, t.count()),
-                    () -> assertEquals(10, t.totalTimeNanos() ,1.0e-12));
+                    () -> assertEquals(10, t.totalTime(TimeUnit.NANOSECONDS) ,1.0e-12));
         }
     }
 
@@ -103,6 +103,6 @@ void recordCallableException(MeterRegistry registry) {
         clock(registry).addAndGet(1, TimeUnit.SECONDS);
 
         assertAll(() -> assertEquals(1L, t.count()),
-                () -> assertEquals(10, t.totalTimeNanos(), 1.0e-12));
+                () -> assertEquals(10, t.totalTime(TimeUnit.NANOSECONDS), 1.0e-12));
     }
 }

starter/micrometer-prometheus-starter/src/main/java/io/micrometer/prometheus/PrometheusLongTaskTimer.java

@@ -21,6 +21,8 @@
 import io.micrometer.core.instrument.util.MeterEquivalence;
 import io.micrometer.prometheus.internal.CustomPrometheusLongTaskTimer;
 
+import java.util.concurrent.TimeUnit;
+
 public class PrometheusLongTaskTimer extends AbstractMeter implements LongTaskTimer {
     private final CustomPrometheusLongTaskTimer.Child timer;
 
@@ -40,13 +42,13 @@ public long stop(long task) {
     }
 
     @Override
-    public long duration(long task) {
-        return timer.duration(task);
+    public double duration(long task, TimeUnit unit) {
+        return timer.duration(task, unit);
     }
 
     @Override
-    public long duration() {
-        return timer.duration();
+    public double duration(TimeUnit unit) {
+        return timer.duration(unit);
     }
 
     @Override

starter/micrometer-prometheus-starter/src/main/java/io/micrometer/prometheus/PrometheusNamingConvention.java

@@ -55,6 +55,7 @@ public String name(String name, Meter.Type type, String baseUnit) {
                 conventionName += "_total";
                 break;
             case Timer:
+            case LongTaskTimer:
                 if(conventionName.endsWith("_duration")) {
                     conventionName += "_seconds";
                 }

starter/micrometer-prometheus-starter/src/main/java/io/micrometer/prometheus/internal/CustomPrometheusLongTaskTimer.java

@@ -18,6 +18,7 @@
 import io.micrometer.core.instrument.Clock;
 import io.micrometer.core.instrument.Meter;
 import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.util.TimeUtils;
 import io.prometheus.client.Collector;
 
 import java.util.Collection;
@@ -27,6 +28,7 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.stream.Stream;
 
@@ -36,6 +38,8 @@
 public class CustomPrometheusLongTaskTimer extends Collector {
     private final Clock clock;
     private final String name;
+    private final String activeTasksName;
+    private final String durationName;
     private final String description;
     private final List<String> tagKeys;
     private final Collection<Child> children = new ConcurrentLinkedQueue<>();
@@ -45,6 +49,9 @@ public CustomPrometheusLongTaskTimer(Meter.Id id, Clock clock) {
         this.description = id.getDescription();
         this.clock = clock;
         this.tagKeys = id.getConventionTags().stream().map(Tag::getKey).collect(toList());
+
+        this.activeTasksName = name + "_active_count";
+        this.durationName = name + "_sum";
     }
 
     public Child child(Iterable<Tag> tags) {
@@ -65,19 +72,8 @@ public class Child implements CustomCollectorChild {
         @Override
         public Stream<MetricFamilySamples.Sample> collect() {
             Stream.Builder<MetricFamilySamples.Sample> samples = Stream.builder();
-
-            List<String> activeTasksKeys = new LinkedList<>(tagKeys);
-            activeTasksKeys.add("statistic");
-            List<String> activeTasksValues = new LinkedList<>(tagValues);
-            activeTasksValues.add("active_tasks");
-            samples.add(new MetricFamilySamples.Sample(name, activeTasksKeys, activeTasksValues, activeTasks()));
-
-            List<String> durationKeys = new LinkedList<>(tagKeys);
-            durationKeys.add("statistic");
-            List<String> durationValues = new LinkedList<>(tagValues);
-            durationValues.add("duration");
-            samples.add(new MetricFamilySamples.Sample(name, durationKeys, durationValues, duration()));
-
+            samples.add(new MetricFamilySamples.Sample(activeTasksName, tagKeys, tagValues, activeTasks()));
+            samples.add(new MetricFamilySamples.Sample(durationName, tagKeys, tagValues, duration(TimeUnit.SECONDS)));
             return samples.build();
         }
 
@@ -97,18 +93,18 @@ public long stop(long task) {
             }
         }
 
-        public long duration(long task) {
+        public double duration(long task, TimeUnit unit) {
             Long startTime = tasks.get(task);
-            return (startTime != null) ? (clock.monotonicTime() - startTime) : -1L;
+            return (startTime != null) ? TimeUtils.nanosToUnit(clock.monotonicTime() - startTime, unit) : -1L;
         }
 
-        public long duration() {
+        public double duration(TimeUnit unit) {
             long now = clock.monotonicTime();
             long sum = 0L;
             for (long startTime : tasks.values()) {
                 sum += now - startTime;
             }
-            return sum;
+            return TimeUtils.nanosToUnit(sum, unit);
         }
 
         public int activeTasks() {

starter/micrometer-prometheus-starter/src/test/java/io/micrometer/prometheus/PrometheusMeterRegistryTest.java

@@ -108,7 +108,7 @@ void helpText() {
             .contains("HELP summary my summary")
             .contains("HELP gauge my gauge")
             .contains("HELP counter_total my counter")
-            .contains("HELP long_task_timer my long task timer");
+            .contains("HELP long_task_timer_duration_seconds my long task timer");
     }
 
     private Condition<Enumeration<Collector.MetricFamilySamples>> withNameAndTagKey(String name, String tagKey) {

starter/micrometer-prometheus-starter/src/test/java/io/micrometer/prometheus/PrometheusNamingConventionTest.java

@@ -39,6 +39,7 @@ void formatTagKey() {
     @Test
     void unitsAreAppendedToTimers() {
         assertThat(convention.name("timer", Meter.Type.Timer)).isEqualTo("timer_duration_seconds");
+        assertThat(convention.name("timer", Meter.Type.LongTaskTimer)).isEqualTo("timer_duration_seconds");
     }
 
     @Test