Measure consecutive maintenance failures

Measuring time since last success results in a wide range of acceptable values,
due to maintenance intervals varying from seconds to as long as half a day.
Measure consecutive failures instead, to simplify alerting thresholds.

4 files changed, 25 insertions, 33 deletions

diff --git a/vespajlib/src/main/java/com/yahoo/concurrent/maintenance/JobMetrics.java b/vespajlib/src/main/java/com/yahoo/concurrent/maintenance/JobMetrics.java
index 4c05d46d782..a43e2156025 100644
--- a/vespajlib/src/main/java/com/yahoo/concurrent/maintenance/JobMetrics.java
+++ b/vespajlib/src/main/java/com/yahoo/concurrent/maintenance/JobMetrics.java
@@ -1,10 +1,7 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.concurrent.maintenance;
 
-import java.time.Clock;
-import java.time.Instant;
 import java.util.Map;
-import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.BiConsumer;
 
@@ -15,26 +12,29 @@ import java.util.function.BiConsumer;
  */
 public class JobMetrics {
 
-    private final Clock clock;
-    private final BiConsumer<String, Instant> metricConsumer;
+    private final BiConsumer<String, Long> metricConsumer;
 
-    private final Map<String, Instant> successfulRuns = new ConcurrentHashMap<>();
+    private final Map<String, Long> incompleteRuns = new ConcurrentHashMap<>();
 
-    public JobMetrics(Clock clock, BiConsumer<String, Instant> metricConsumer) {
-        this.clock = Objects.requireNonNull(clock);
+    public JobMetrics(BiConsumer<String, Long> metricConsumer) {
         this.metricConsumer = metricConsumer;
     }
 
+    /** Record a run for given job */
+    public void recordRunOf(String job) {
+        incompleteRuns.compute(job, (ignored, run) -> run == null ? 1 : ++run);
+    }
+
     /** Record successful run of given job */
     public void recordSuccessOf(String job) {
-        successfulRuns.put(job, clock.instant());
+        incompleteRuns.put(job, 0L);
     }
 
     /** Forward metrics for given job to metric consumer */
     public void forward(String job) {
-        Instant lastSuccess = successfulRuns.get(job);
-        if (lastSuccess != null) {
-            metricConsumer.accept(job, lastSuccess);
+        Long incompleteRuns = this.incompleteRuns.get(job);
+        if (incompleteRuns != null) {
+            metricConsumer.accept(job, incompleteRuns);
         }
     }
 
diff --git a/vespajlib/src/main/java/com/yahoo/concurrent/maintenance/Maintainer.java b/vespajlib/src/main/java/com/yahoo/concurrent/maintenance/Maintainer.java
index 0385c27536d..eb9b91c812c 100644
--- a/vespajlib/src/main/java/com/yahoo/concurrent/maintenance/Maintainer.java
+++ b/vespajlib/src/main/java/com/yahoo/concurrent/maintenance/Maintainer.java
@@ -85,6 +85,7 @@ public abstract class Maintainer implements Runnable, AutoCloseable {
     public final void lockAndMaintain() {
         try (var lock = jobControl.lockJob(name())) {
             try {
+                jobMetrics.recordRunOf(name());
                 if (maintain()) jobMetrics.recordSuccessOf(name());
             } finally {
                 // Always forward metrics
diff --git a/vespajlib/src/test/java/com/yahoo/concurrent/maintenance/MaintainerTest.java b/vespajlib/src/test/java/com/yahoo/concurrent/maintenance/MaintainerTest.java
index 47ed010e95e..2bfaad894a5 100644
--- a/vespajlib/src/test/java/com/yahoo/concurrent/maintenance/MaintainerTest.java
+++ b/vespajlib/src/test/java/com/yahoo/concurrent/maintenance/MaintainerTest.java
@@ -1,16 +1,14 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.concurrent.maintenance;
 
-import com.yahoo.test.ManualClock;
 import org.junit.Test;
 
 import java.time.Duration;
 import java.time.Instant;
 import java.util.List;
-import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.atomic.AtomicLong;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
 
 /**
  * @author freva
@@ -41,37 +39,31 @@ public class MaintainerTest {
 
     @Test
     public void success_metric() {
-        ManualClock clock = new ManualClock();
-        AtomicReference<Instant> lastSuccess = new AtomicReference<>();
-        JobMetrics jobMetrics = new JobMetrics(clock, (job, instant) -> lastSuccess.set(instant));
+        AtomicLong consecutiveFailures = new AtomicLong();
+        JobMetrics jobMetrics = new JobMetrics((job, count) -> consecutiveFailures.set(count));
         TestMaintainer maintainer = new TestMaintainer(jobMetrics);
 
-        // Maintainer not successful yet
+        // Maintainer fails twice in a row
         maintainer.successOnNextRun(false).run();
-        assertNull(lastSuccess.get());
+        assertEquals(1, consecutiveFailures.get());
+        maintainer.successOnNextRun(false).run();
+        assertEquals(2, consecutiveFailures.get());
 
         // Maintainer runs successfully
-        clock.advance(Duration.ofHours(1));
-        Instant lastSuccess0 = clock.instant();
         maintainer.successOnNextRun(true).run();
-        assertEquals(lastSuccess0, lastSuccess.get());
+        assertEquals(0, consecutiveFailures.get());
 
         // Maintainer runs successfully again
-        clock.advance(Duration.ofHours(2));
-        Instant lastSuccess1 = clock.instant();
         maintainer.run();
-        assertEquals(lastSuccess1, lastSuccess.get());
+        assertEquals(0, consecutiveFailures.get());
 
         // Maintainer throws
-        clock.advance(Duration.ofHours(5));
         maintainer.throwOnNextRun(true).run();
-        assertEquals("Time of successful run is unchanged", lastSuccess1, lastSuccess.get());
+        assertEquals(1, consecutiveFailures.get());
 
         // Maintainer recovers
-        clock.advance(Duration.ofHours(3));
-        Instant lastSuccess2 = clock.instant();
         maintainer.throwOnNextRun(false).run();
-        assertEquals(lastSuccess2, lastSuccess.get());
+        assertEquals(0, consecutiveFailures.get());
     }
 
 }
diff --git a/vespajlib/src/test/java/com/yahoo/concurrent/maintenance/TestMaintainer.java b/vespajlib/src/test/java/com/yahoo/concurrent/maintenance/TestMaintainer.java
index 0ea24fb6c2b..5eae643fe40 100644
--- a/vespajlib/src/test/java/com/yahoo/concurrent/maintenance/TestMaintainer.java
+++ b/vespajlib/src/test/java/com/yahoo/concurrent/maintenance/TestMaintainer.java
@@ -1,7 +1,6 @@
 // Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.concurrent.maintenance;
 
-import java.time.Clock;
 import java.time.Duration;
 
 /**
@@ -22,7 +21,7 @@ class TestMaintainer extends Maintainer {
     }
 
     public TestMaintainer(String name, JobControl jobControl) {
-        this(name, jobControl, new JobMetrics(Clock.systemUTC(), (job, instant) -> {}));
+        this(name, jobControl, new JobMetrics((job, instant) -> {}));
     }
 
     public int totalRuns() {