feat: added subscriber metric

Signed-off-by: Matt Peterson <[email protected]>
hashgraph · Aug 8, 2024 · 8bae1da · 8bae1da
1 parent 45b2045
commit 8bae1da
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Showing 3 changed files with 19 additions and 1 deletion.
diff --git a/server/src/main/java/com/hedera/block/server/mediator/LiveStreamMediatorImpl.java b/server/src/main/java/com/hedera/block/server/mediator/LiveStreamMediatorImpl.java
@@ -30,6 +30,7 @@
 import com.lmax.disruptor.RingBuffer;
 import com.lmax.disruptor.dsl.Disruptor;
 import com.lmax.disruptor.util.DaemonThreadFactory;
+import com.swirlds.metrics.api.LongGauge;
 import edu.umd.cs.findbugs.annotations.NonNull;
 import java.io.IOException;
 import java.util.Map;
@@ -164,6 +165,8 @@ public void subscribe(
 
         // Keep track of the subscriber
         subscribers.put(handler, batchEventProcessor);
+
+        updateSubscriberMetrics();
     }
 
     @Override
@@ -183,6 +186,8 @@ public void unsubscribe(
             // Remove the gating sequence from the ring buffer
             ringBuffer.removeGatingSequence(batchEventProcessor.getSequence());
         }
+
+        updateSubscriberMetrics();
     }
 
     @Override
@@ -200,4 +205,10 @@ private static SubscribeStreamResponse buildEndStreamResponse() {
                 .setStatus(SubscribeStreamResponse.SubscribeStreamResponseCode.READ_STREAM_SUCCESS)
                 .build();
     }
+
+    private void updateSubscriberMetrics() {
+        @NonNull final MetricsService metricsService = blockNodeContext.metricsService();
+        @NonNull final LongGauge longGauge = metricsService.subscriberGauge;
+        longGauge.set(subscribers.size());
+    }
 }
diff --git a/server/src/main/java/com/hedera/block/server/metrics/MetricsService.java b/server/src/main/java/com/hedera/block/server/metrics/MetricsService.java
@@ -37,13 +37,20 @@ public class MetricsService {
             new Counter.Config(LIVE_CATEGORY, "liveBlockItemCounter")
                     .withDescription("Live BlockItem Counter");
 
+    // Subscriber Gauge
+    private static final String SUBSCRIBER_CATEGORY = "subscriber";
+    private static final LongGauge.Config SUBSCRIBER_GAUGE =
+            new LongGauge.Config(SUBSCRIBER_CATEGORY, "subscriberGauge")
+                    .withDescription("Subscriber Gauge");
+
     /** An example gauge. */
     public final LongGauge exampleGauge;
 
     /** An example counter. */
     public final Counter exampleCounter;
 
     public final Counter liveBlockItemCounter;
+    public final LongGauge subscriberGauge;
 
     /**
      * Creates a new instance of {@link MetricsService}.
@@ -55,5 +62,6 @@ public MetricsService(@NonNull final Metrics metrics) {
         this.exampleCounter = metrics.getOrCreate(EXAMPLE_COUNTER);
 
         this.liveBlockItemCounter = metrics.getOrCreate(LIVE_BLOCK_ITEM_COUNTER);
+        this.subscriberGauge = metrics.getOrCreate(SUBSCRIBER_GAUGE);
     }
 }
diff --git a/server/src/test/java/com/hedera/block/server/BlockStreamServiceIT.java b/server/src/test/java/com/hedera/block/server/BlockStreamServiceIT.java
@@ -175,7 +175,6 @@ public void testSubscribeBlockStream() throws IOException {
         // Calling onNext() with a BlockItem
         streamObserver.onNext(publishStreamRequest);
 
-
         // Verify the counter was incremented
         assertEquals(1, blockNodeContext.metricsService().liveBlockItemCounter.get());