refactor: MetricsService refactor to use an interface (#142)

Signed-off-by: Alfredo Gutierrez <[email protected]>

server/src/main/java/com/hedera/block/server/BlockStreamService.java

@@ -202,7 +202,7 @@ private void singleBlock(
                             fromPbjSingleBlockSuccessResponse(blockOpt.get()));
 
                     final MetricsService metricsService = blockNodeContext.metricsService();
-                    metricsService.singleBlocksRetrieved.increment();
+                    metricsService.singleBlocksRetrieved().increment();
                 } else {
                     LOGGER.log(DEBUG, "Block number {0} not found", blockNumber);
                     singleBlockResponseStreamObserver.onNext(buildSingleBlockNotFoundResponse());

server/src/main/java/com/hedera/block/server/mediator/LiveStreamMediatorImpl.java

@@ -121,7 +121,7 @@ public void publish(@NonNull final BlockItem blockItem) throws IOException {
             ringBuffer.publishEvent((event, sequence) -> event.set(subscribeStreamResponse));
 
             // Increment the block item counter
-            metricsService.liveBlockItems.increment();
+            metricsService.liveBlockItems().increment();
 
             try {
                 // Persist the BlockItem
@@ -211,7 +211,7 @@ private static SubscribeStreamResponse buildEndStreamResponse() {
 
     private void updateSubscriberMetrics() {
         @NonNull final MetricsService metricsService = blockNodeContext.metricsService();
-        @NonNull final LongGauge longGauge = metricsService.subscribers;
+        @NonNull final LongGauge longGauge = metricsService.subscribers();
         longGauge.set(subscribers.size());
     }
 }

server/src/main/java/com/hedera/block/server/metrics/MetricsInjectionModule.java

@@ -19,6 +19,7 @@
 import com.swirlds.common.metrics.platform.DefaultMetricsProvider;
 import com.swirlds.config.api.Configuration;
 import com.swirlds.metrics.api.Metrics;
+import dagger.Binds;
 import dagger.Module;
 import dagger.Provides;
 import javax.inject.Singleton;
@@ -30,14 +31,12 @@ public interface MetricsInjectionModule {
     /**
      * Provides the metrics service.
      *
-     * @param metrics the metrics to be used by the service
+     * @param metricsService the metrics service to be used
      * @return the metrics service
      */
     @Singleton
-    @Provides
-    static MetricsService provideMetricsService(Metrics metrics) {
-        return new MetricsService(metrics);
-    }
+    @Binds
+    MetricsService bindMetricsService(MetricsServiceImpl metricsService);
 
     /**
      * Provides the metrics.

server/src/main/java/com/hedera/block/server/metrics/MetricsService.java

@@ -18,57 +18,39 @@
 
 import com.swirlds.metrics.api.Counter;
 import com.swirlds.metrics.api.LongGauge;
-import com.swirlds.metrics.api.Metrics;
 import edu.umd.cs.findbugs.annotations.NonNull;
 
-/**
- * Use member variables of this class to update metric data for the Hedera Block Node.
- *
- * <p>Metrics are updated by calling the appropriate method on the metric object instance. For
- * example, to increment a counter, call {@link Counter#increment()}.
- */
-public class MetricsService {
-
-    private static final String CATEGORY = "hedera_block_node";
-
-    // Live BlockItem Counter
-    private static final Counter.Config LIVE_BLOCK_ITEM_COUNTER =
-            new Counter.Config(CATEGORY, "live_block_items").withDescription("Live BlockItems");
-
-    // Block Persistence Counter
-    private static final Counter.Config BLOCK_PERSISTENCE_COUNTER =
-            new Counter.Config(CATEGORY, "blocks_persisted").withDescription("Blocks Persisted");
-
-    // Subscriber Gauge
-    private static final LongGauge.Config SUBSCRIBER_GAUGE =
-            new LongGauge.Config(CATEGORY, "subscribers").withDescription("Subscribers");
-
-    // Single Block Retrieved Counter
-    private static final Counter.Config SINGLE_BLOCK_RETRIEVED_COUNTER =
-            new Counter.Config(CATEGORY, "single_blocks_retrieved")
-                    .withDescription("Single Blocks Retrieved");
-
-    /** Update the counter of live block items transiting via the live stream. */
-    public final Counter liveBlockItems;
-
-    /** Update the counter of blocks persisted to storage. */
-    public final Counter blocksPersisted;
+/** Use member variables of this class to update metric data for the Hedera Block Node. */
+public interface MetricsService {
+    /**
+     * Update the counter of live block items transiting via the live stream.
+     *
+     * @return use this metric to increase the counter of block items received
+     */
+    @NonNull
+    Counter liveBlockItems();
 
-    /** Update the counter of single blocks retrieved from storage. */
-    public final Counter singleBlocksRetrieved;
+    /**
+     * Update the counter of blocks persisted to storage.
+     *
+     * @return use this counter to increase the amount of blocks persisted to disk
+     */
+    @NonNull
+    Counter blocksPersisted();
 
-    /** Update the gauge of subscribers currently consuming to the live stream. */
-    public final LongGauge subscribers;
+    /**
+     * Update the counter of single blocks retrieved from storage.
+     *
+     * @return use this metric to increase the counter of single blocks retrieved
+     */
+    @NonNull
+    Counter singleBlocksRetrieved();
 
     /**
-     * Create singleton instance of metrics service to be used throughout the application.
+     * Update the gauge of subscribers currently consuming to the live stream.
      *
-     * @param metrics the metrics instance
+     * @return Use this to increase or decrease the amount of current subscribers to the live stream
      */
-    public MetricsService(@NonNull final Metrics metrics) {
-        this.liveBlockItems = metrics.getOrCreate(LIVE_BLOCK_ITEM_COUNTER);
-        this.blocksPersisted = metrics.getOrCreate(BLOCK_PERSISTENCE_COUNTER);
-        this.singleBlocksRetrieved = metrics.getOrCreate(SINGLE_BLOCK_RETRIEVED_COUNTER);
-        this.subscribers = metrics.getOrCreate(SUBSCRIBER_GAUGE);
-    }
+    @NonNull
+    LongGauge subscribers();
 }

server/src/main/java/com/hedera/block/server/metrics/MetricsServiceImpl.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2024 Hedera Hashgraph, LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.hedera.block.server.metrics;
+
+import com.swirlds.metrics.api.Counter;
+import com.swirlds.metrics.api.LongGauge;
+import com.swirlds.metrics.api.Metrics;
+import edu.umd.cs.findbugs.annotations.NonNull;
+import javax.inject.Inject;
+
+/**
+ * Use member variables of this class to update metric data for the Hedera Block Node.
+ *
+ * <p>Metrics are updated by calling the appropriate method on the metric object instance. For
+ * example, to increment a counter, call {@link Counter#increment()}.
+ */
+public class MetricsServiceImpl implements MetricsService {
+
+    private static final String CATEGORY = "hedera_block_node";
+
+    // Live BlockItem Counter
+    private static final Counter.Config LIVE_BLOCK_ITEM_COUNTER =
+            new Counter.Config(CATEGORY, "live_block_items").withDescription("Live BlockItems");
+
+    // Block Persistence Counter
+    private static final Counter.Config BLOCK_PERSISTENCE_COUNTER =
+            new Counter.Config(CATEGORY, "blocks_persisted").withDescription("Blocks Persisted");
+
+    // Subscriber Gauge
+    private static final LongGauge.Config SUBSCRIBER_GAUGE =
+            new LongGauge.Config(CATEGORY, "subscribers").withDescription("Subscribers");
+
+    // Single Block Retrieved Counter
+    private static final Counter.Config SINGLE_BLOCK_RETRIEVED_COUNTER =
+            new Counter.Config(CATEGORY, "single_blocks_retrieved")
+                    .withDescription("Single Blocks Retrieved");
+
+    private final Counter liveBlockItems;
+
+    private final Counter blocksPersisted;
+
+    private final Counter singleBlocksRetrieved;
+
+    private final LongGauge subscribers;
+
+    /** Update the counter of live block items transiting via the live stream. */
+    @Override
+    @NonNull
+    public final Counter liveBlockItems() {
+        return liveBlockItems;
+    }
+
+    /** Update the counter of blocks persisted to storage. */
+    @Override
+    @NonNull
+    public final Counter blocksPersisted() {
+        return blocksPersisted;
+    }
+
+    /** Update the counter of single blocks retrieved from storage. */
+    @Override
+    @NonNull
+    public final Counter singleBlocksRetrieved() {
+        return singleBlocksRetrieved;
+    }
+
+    /** Update the gauge of subscribers currently consuming to the live stream. */
+    @Override
+    @NonNull
+    public final LongGauge subscribers() {
+        return subscribers;
+    }
+
+    /**
+     * Create singleton instance of metrics service to be used throughout the application.
+     *
+     * @param metrics the metrics instance
+     */
+    @Inject
+    public MetricsServiceImpl(@NonNull final Metrics metrics) {
+        this.liveBlockItems = metrics.getOrCreate(LIVE_BLOCK_ITEM_COUNTER);
+        this.blocksPersisted = metrics.getOrCreate(BLOCK_PERSISTENCE_COUNTER);
+        this.singleBlocksRetrieved = metrics.getOrCreate(SINGLE_BLOCK_RETRIEVED_COUNTER);
+        this.subscribers = metrics.getOrCreate(SUBSCRIBER_GAUGE);
+    }
+}

server/src/main/java/com/hedera/block/server/persistence/storage/write/BlockAsDirWriter.java

@@ -163,7 +163,7 @@ private void resetState(@NonNull final BlockItem blockItem) throws IOException {
 
         // Increment the block counter
         final MetricsService metricsService = blockNodeContext.metricsService();
-        metricsService.blocksPersisted.increment();
+        metricsService.blocksPersisted().increment();
     }
 
     private void repairPermissions(@NonNull final Path path) throws IOException {

server/src/test/java/com/hedera/block/server/BlockStreamServiceIntegrationTest.java

@@ -230,7 +230,7 @@ public void testSubscribeBlockStream() throws IOException {
         streamObserver.onNext(fromPbj(publishStreamRequest));
 
         // Verify the counter was incremented
-        assertEquals(1, blockNodeContext.metricsService().liveBlockItems.get());
+        assertEquals(1, blockNodeContext.metricsService().liveBlockItems().get());
 
         verify(blockWriter, timeout(testTimeout).times(1)).write(blockItems.getFirst());
 

server/src/test/java/com/hedera/block/server/config/BlockNodeContextTest.java

@@ -20,6 +20,7 @@
 import static org.mockito.Mockito.*;
 
 import com.hedera.block.server.metrics.MetricsService;
+import com.hedera.block.server.metrics.MetricsServiceImpl;
 import com.swirlds.config.api.Configuration;
 import org.junit.jupiter.api.Test;
 
@@ -28,7 +29,7 @@ class BlockNodeContextTest {
     @Test
     void BlockNodeContext_initializesWithMetricsAndConfiguration() {
         Configuration configuration = mock(Configuration.class);
-        MetricsService metricsService = mock(MetricsService.class);
+        MetricsService metricsService = mock(MetricsServiceImpl.class);
 
         BlockNodeContext context = new BlockNodeContext(metricsService, configuration);
 

server/src/test/java/com/hedera/block/server/config/TestConfigBuilder.java

@@ -166,6 +166,7 @@ public TestConfigBuilder withValue(
      * @return the created configuration
      */
     @NonNull
+    @SuppressWarnings({"removal"})
     public Configuration getOrCreateConfig() {
         try (final Locked ignore = configLock.lock()) {
             if (configuration == null) {

server/src/test/java/com/hedera/block/server/mediator/LiveStreamMediatorImplTest.java

@@ -131,7 +131,7 @@ public void testUnsubscribeEach() throws InterruptedException, IOException {
                 "Expected the mediator to have unsubscribed observer3");
 
         // Confirm the counter was never incremented
-        assertEquals(0, blockNodeContext.metricsService().liveBlockItems.get());
+        assertEquals(0, blockNodeContext.metricsService().liveBlockItems().get());
     }
 
     @Test
@@ -148,7 +148,7 @@ blockWriter, blockNodeContext, new ServiceStatusImpl())
         streamMediator.publish(blockItem);
 
         // Verify the counter was incremented
-        assertEquals(1, blockNodeContext.metricsService().liveBlockItems.get());
+        assertEquals(1, blockNodeContext.metricsService().liveBlockItems().get());
 
         // Confirm the BlockStorage write method was
         // called despite the absence of subscribers
@@ -201,7 +201,7 @@ blockWriter, blockNodeContext, new ServiceStatusImpl())
         // Acting as a producer, notify the mediator of a new block
         streamMediator.publish(blockItem);
 
-        assertEquals(1, blockNodeContext.metricsService().liveBlockItems.get());
+        assertEquals(1, blockNodeContext.metricsService().liveBlockItems().get());
 
         // Confirm each subscriber was notified of the new block
         verify(streamObserver1, timeout(testTimeout).times(1))
@@ -248,7 +248,7 @@ blockWriter, blockNodeContext, new ServiceStatusImpl())
         streamMediator.unsubscribe(concreteObserver3);
 
         // Confirm the counter was never incremented
-        assertEquals(0, blockNodeContext.metricsService().liveBlockItems.get());
+        assertEquals(0, blockNodeContext.metricsService().liveBlockItems().get());
     }
 
     @Test
@@ -277,7 +277,7 @@ blockWriter, blockNodeContext, new ServiceStatusImpl())
         testConsumerBlockItemObserver.getOnCancel().run();
 
         // Verify the block item incremented the counter
-        assertEquals(1, blockNodeContext.metricsService().liveBlockItems.get());
+        assertEquals(1, blockNodeContext.metricsService().liveBlockItems().get());
 
         // Verify the event made it to the consumer
         verify(serverCallStreamObserver, timeout(testTimeout).times(1)).setOnCancelHandler(any());
@@ -313,7 +313,7 @@ blockWriter, blockNodeContext, new ServiceStatusImpl())
         testConsumerBlockItemObserver.getOnClose().run();
 
         // Verify the block item incremented the counter
-        assertEquals(1, blockNodeContext.metricsService().liveBlockItems.get());
+        assertEquals(1, blockNodeContext.metricsService().liveBlockItems().get());
 
         // Verify the event made it to the consumer
         verify(serverCallStreamObserver, timeout(testTimeout).times(1)).setOnCancelHandler(any());
@@ -348,7 +348,7 @@ blockWriter, blockNodeContext, new ServiceStatusImpl())
             streamMediator.publish(secondBlockItem);
 
             // Confirm the counter was incremented only once
-            assertEquals(1, blockNodeContext.metricsService().liveBlockItems.get());
+            assertEquals(1, blockNodeContext.metricsService().liveBlockItems().get());
 
             // Confirm the BlockPersistenceHandler write method was only called
             // once despite the second block being published.

server/src/test/java/com/hedera/block/server/metrics/MetricsInjectionModuleTest.java

@@ -25,23 +25,11 @@
 import java.io.IOException;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
-import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 
 @ExtendWith(MockitoExtension.class)
 class MetricsInjectionModuleTest {
 
-    @Mock private Metrics metrics;
-
-    @Test
-    void testProvideMetricsService() {
-        // Call the method under test
-        MetricsService metricsService = MetricsInjectionModule.provideMetricsService(metrics);
-
-        // Verify that the metricsService is correctly instantiated
-        assertNotNull(metricsService);
-    }
-
     @Test
     void testProvideMetrics() throws IOException {
         BlockNodeContext context = TestConfigUtil.getTestBlockNodeContext();