Add timer capability to the Prometheus metrics

Co-authored-by: Ioannis Panagiotas <ioannis.panagiotas@neotechnology.com>

algo/src/main/java/org/neo4j/gds/algorithms/community/BasicAlgorithmRunner.java

@@ -115,15 +115,16 @@ public <A extends Algorithm<R>, R, C extends AlgoBaseConfig> AlgorithmComputatio
         );
 
         // run the algorithm
-        try {
-            algorithmMetricsService.started(algorithmFactory.taskName());
+        var algorithmMetric = algorithmMetricsService.create(algorithmFactory.taskName());
+        try(algorithmMetric) {
+            algorithmMetric.start();
             var algorithmResult = algorithm.compute();
 
             return AlgorithmComputationResult.of(algorithmResult, graph, graphStore, algorithm.getTerminationFlag());
         } catch (Exception e) {
             log.warn("Computation failed", e);
             algorithm.getProgressTracker().endSubTaskWithFailure();
-            algorithmMetricsService.failed(algorithmFactory.taskName());
+            algorithmMetric.failed();
             throw e;
         }
     }

algo/src/test/java/org/neo4j/gds/algorithms/community/BasicAlgorithmRunnerTest.java

@@ -24,6 +24,7 @@
 import org.neo4j.gds.Algorithm;
 import org.neo4j.gds.GraphAlgorithmFactory;
 import org.neo4j.gds.algorithms.AlgorithmMemoryValidationService;
+import org.neo4j.gds.algorithms.metrics.AlgorithmMetric;
 import org.neo4j.gds.algorithms.metrics.AlgorithmMetricsService;
 import org.neo4j.gds.api.DatabaseId;
 import org.neo4j.gds.api.Graph;
@@ -40,6 +41,7 @@
 
 import static org.assertj.core.api.Assertions.assertThatException;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.Mockito.RETURNS_DEEP_STUBS;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
@@ -58,7 +60,9 @@ void shouldRegisterAlgorithmMetricCountForSuccess() {
         when(graphStoreCatalogServiceMock.getGraphWithGraphStore(any(), any(), any(), any(), any()))
             .thenReturn(Pair.of(graphMock, mock(GraphStore.class)));
 
+        var algorithmMetricMock = mock(AlgorithmMetric.class);
         var algorithmMetricsServiceMock = mock(AlgorithmMetricsService.class);
+        when(algorithmMetricsServiceMock.create(anyString())).thenReturn(algorithmMetricMock);
 
         var logMock = mock(Log.class);
         when(logMock.getNeo4jLog()).thenReturn(Neo4jProxy.testLog());
@@ -87,9 +91,14 @@ void shouldRegisterAlgorithmMetricCountForSuccess() {
             DatabaseId.EMPTY
         );
 
-        verify(algorithmMetricsServiceMock, times(1)).started("TestingMetrics");
-        verify(algorithmMetricsServiceMock, times(0)).failed("TestingMetrics");
-        verifyNoMoreInteractions(algorithmMetricsServiceMock);
+        verify(algorithmMetricsServiceMock, times(1)).create("TestingMetrics");
+        verify(algorithmMetricMock, times(1)).start();
+        verify(algorithmMetricMock, times(1)).close();
+        verify(algorithmMetricMock, times(0)).failed();
+        verifyNoMoreInteractions(
+            algorithmMetricsServiceMock,
+            algorithmMetricMock
+        );
     }
 
 
@@ -102,7 +111,9 @@ void shouldRegisterAlgorithmMetricCountForFailure() {
         when(graphStoreCatalogServiceMock.getGraphWithGraphStore(any(), any(), any(), any(), any()))
             .thenReturn(Pair.of(graphMock, mock(GraphStore.class)));
 
+        var algorithmMetricMock = mock(AlgorithmMetric.class);
         var algorithmMetricsServiceMock = mock(AlgorithmMetricsService.class);
+        when(algorithmMetricsServiceMock.create(anyString())).thenReturn(algorithmMetricMock);
 
         var logMock = mock(Log.class);
         when(logMock.getNeo4jLog()).thenReturn(Neo4jProxy.testLog());
@@ -134,9 +145,14 @@ void shouldRegisterAlgorithmMetricCountForFailure() {
             )
         ).withMessage("Ooops");
 
-        verify(algorithmMetricsServiceMock, times(1)).started("TestingMetrics");
-        verify(algorithmMetricsServiceMock, times(1)).failed("TestingMetrics");
-        verifyNoMoreInteractions(algorithmMetricsServiceMock);
+        verify(algorithmMetricsServiceMock, times(1)).create("TestingMetrics");
+        verify(algorithmMetricMock, times(1)).start();
+        verify(algorithmMetricMock, times(1)).close();
+        verify(algorithmMetricMock, times(1)).failed();
+        verifyNoMoreInteractions(
+            algorithmMetricsServiceMock,
+            algorithmMetricMock
+        );
     }
 
 }

algorithm-metrics-api/src/main/java/org/neo4j/gds/algorithms/metrics/AlgorithmMetric.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) "Neo4j"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.gds.algorithms.metrics;
+
+public abstract class AlgorithmMetric implements AutoCloseable {
+
+    protected final String algorithm;
+
+    protected AlgorithmMetric(String algorithm) {
+        this.algorithm = algorithm;
+    }
+
+    public abstract void start();
+
+    public abstract void failed();
+
+    @Override
+    public abstract void close();
+}

algorithm-metrics-api/src/main/java/org/neo4j/gds/algorithms/metrics/AlgorithmMetricRegistrar.java

@@ -21,6 +21,6 @@
 
 public interface AlgorithmMetricRegistrar {
 
-    void started(String algorithm);
-    void failed(String algorithm);
+    AlgorithmMetric create(String algorithm);
+
 }

algorithm-metrics-api/src/main/java/org/neo4j/gds/algorithms/metrics/AlgorithmMetricsService.java

@@ -27,12 +27,7 @@ public AlgorithmMetricsService(AlgorithmMetricRegistrar metricRegistrar) {
         this.metricRegistrar = metricRegistrar;
     }
 
-    public void started(String algorithm) {
-        metricRegistrar.started(algorithm);
+    public AlgorithmMetric create(String algorithm) {
+        return metricRegistrar.create(algorithm);
     }
-
-    public void failed(String algorithm) {
-        metricRegistrar.failed(algorithm);
-    }
-
 }

algorithm-metrics-api/src/main/java/org/neo4j/gds/algorithms/metrics/PassthroughAlgorithmMetric.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) "Neo4j"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.gds.algorithms.metrics;
+
+public final class PassthroughAlgorithmMetric extends AlgorithmMetric {
+
+    PassthroughAlgorithmMetric(String algorithm) {
+        super(algorithm);
+    }
+
+    @Override
+    public void start() {}
+
+    @Override
+    public void failed() {}
+
+    @Override
+    public void close() {}
+}

algorithm-metrics-api/src/main/java/org/neo4j/gds/algorithms/metrics/PassthroughAlgorithmMetricRegistrar.java

@@ -25,12 +25,7 @@
 public class PassthroughAlgorithmMetricRegistrar implements AlgorithmMetricRegistrar {
 
     @Override
-    public void started(String algorithm) {
-
-    }
-
-    @Override
-    public void failed(String algorithm) {
-
+    public AlgorithmMetric create(String algorithm) {
+        return new PassthroughAlgorithmMetric(algorithm);
     }
 }

algorithm-metrics-api/src/test/java/org/neo4j/gds/algorithms/metrics/AlgorithmMetricsServiceTest.java

@@ -29,30 +29,17 @@
 class AlgorithmMetricsServiceTest {
 
     @Test
-    void shouldRegisterStarted() {
+    void shouldCreateAlgorithmMetric() {
         // given
         var registrarMock = mock(AlgorithmMetricRegistrar.class);
         var metricsService = new AlgorithmMetricsService(registrarMock);
 
         // when
-        metricsService.started("foo");
+        metricsService.create("foo");
 
         // then
-        verify(registrarMock, times(1)).started("foo");
+        verify(registrarMock, times(1)).create("foo");
         verifyNoMoreInteractions(registrarMock);
     }
 
-    @Test
-    void shouldRegisterFailed() {
-        // given
-        var registrarMock = mock(AlgorithmMetricRegistrar.class);
-        var metricsService = new AlgorithmMetricsService(registrarMock);
-
-        // when
-        metricsService.failed("foo");
-
-        // then
-        verify(registrarMock, times(1)).failed("foo");
-        verifyNoMoreInteractions(registrarMock);
-    }
 }