Add access to network engine stats

Added API call GET /peers/enginestats to allow external monitoring.

Extract all engine stats in one synchronized block, instead of
separate calls, for better consistency.

src/main/java/org/qortal/api/resource/PeersResource.java

@@ -31,6 +31,7 @@ import org.qortal.network.PeerAddress;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
+import org.qortal.utils.ExecuteProduceConsume;
 
 @Path("/peers")
 @Tag(name = "Peers")
@@ -108,6 +109,29 @@ public class PeersResource {
 		return Network.getInstance().getSelfPeers();
 	}
 
+	@GET
+	@Path("/enginestats")
+	@Operation(
+		summary = "Fetch statistics snapshot for networking engine",
+		responses = {
+			@ApiResponse(
+				content = @Content(
+					mediaType = MediaType.APPLICATION_JSON,
+					array = @ArraySchema(
+						schema = @Schema(
+							implementation = ExecuteProduceConsume.StatsSnapshot.class
+						)
+					)
+				)
+			)
+		}
+	)
+	public ExecuteProduceConsume.StatsSnapshot getEngineStats() {
+		Security.checkApiCallAllowed(request);
+
+		return Network.getInstance().getStatsSnapshot();
+	}
+
 	@POST
 	@Operation(
 		summary = "Add new peer address",

src/main/java/org/qortal/network/Network.java

@@ -56,6 +56,7 @@ import org.qortal.repository.Repository;
 import org.qortal.repository.RepositoryManager;
 import org.qortal.settings.Settings;
 import org.qortal.utils.ExecuteProduceConsume;
+import org.qortal.utils.ExecuteProduceConsume.StatsSnapshot;
 import org.qortal.utils.NTP;
 
 // For managing peers
@@ -199,6 +200,10 @@ public class Network {
 		return this.maxMessageSize;
 	}
 
+	public StatsSnapshot getStatsSnapshot() {
+		return this.networkEPC.getStatsSnapshot();
+	}
+
 	// Peer lists
 
 	public List<Peer> getConnectedPeers() {

src/main/java/org/qortal/utils/ExecuteProduceConsume.java

@@ -5,11 +5,26 @@ import java.util.concurrent.Executors;
 import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
 
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 public abstract class ExecuteProduceConsume implements Runnable {
 
+	@XmlAccessorType(XmlAccessType.FIELD)
+	public static class StatsSnapshot {
+		public int activeThreadCount = 0;
+		public int greatestActiveThreadCount = 0;
+		public int consumerCount = 0;
+		public int tasksProduced = 0;
+		public int tasksConsumed = 0;
+
+		public StatsSnapshot() {
+		}
+	}
+
 	private final String className;
 	private final Logger logger;
 
@@ -51,28 +66,18 @@ public abstract class ExecuteProduceConsume implements Runnable {
 		return this.executor.awaitTermination(timeout, TimeUnit.MILLISECONDS);
 	}
 
-	public int getActiveThreadCount() {
+	public StatsSnapshot getStatsSnapshot() {
-		synchronized (this) {
+		StatsSnapshot snapshot = new StatsSnapshot();
-			return this.activeThreadCount;
-		}
-	}
 
-	public int getGreatestActiveThreadCount() {
 		synchronized (this) {
-			return this.greatestActiveThreadCount;
+			snapshot.activeThreadCount = this.activeThreadCount;
+			snapshot.greatestActiveThreadCount = this.greatestActiveThreadCount;
+			snapshot.consumerCount = this.consumerCount;
+			snapshot.tasksProduced = this.tasksProduced;
+			snapshot.tasksConsumed = this.tasksConsumed;
 		}
-	}
 
-	public int getTasksProduced() {
+		return snapshot;
-		synchronized (this) {
-			return this.tasksProduced;
-		}
-	}
-
-	public int getTasksConsumed() {
-		synchronized (this) {
-			return this.tasksConsumed;
-		}
 	}
 
 	/**

src/test/java/org/qortal/test/EPCTests.java

@@ -11,6 +11,7 @@ import java.util.concurrent.TimeUnit;
 
 import org.junit.Test;
 import org.qortal.utils.ExecuteProduceConsume;
+import org.qortal.utils.ExecuteProduceConsume.StatsSnapshot;
 
 public class EPCTests {
 
@@ -60,13 +61,12 @@ public class EPCTests {
 		ScheduledExecutorService statusExecutor = Executors.newSingleThreadScheduledExecutor();
 
 		statusExecutor.scheduleAtFixedRate(() -> {
-			synchronized (testEPC) {
+			StatsSnapshot snapshot = testEPC.getStatsSnapshot();
-				final long seconds = (System.currentTimeMillis() - start) / 1000L;
+			final long seconds = (System.currentTimeMillis() - start) / 1000L;
-				System.out.println(String.format("After %d second%s, active threads: %d, greatest thread count: %d, tasks produced: %d, tasks consumed: %d",
+			System.out.println(String.format("After %d second%s, active threads: %d, greatest thread count: %d, tasks produced: %d, tasks consumed: %d",
-						seconds, (seconds != 1 ? "s" : ""),
+					seconds, (seconds != 1 ? "s" : ""),
-						testEPC.getActiveThreadCount(), testEPC.getGreatestActiveThreadCount(),
+					snapshot.activeThreadCount, snapshot.greatestActiveThreadCount,
-						testEPC.getTasksProduced(), testEPC.getTasksConsumed()));
+					snapshot.tasksProduced, snapshot.tasksConsumed));
-			}
 		}, 1L, 1L, TimeUnit.SECONDS);
 
 		// Let it run for a minute
@@ -78,10 +78,10 @@ public class EPCTests {
 		final long after = System.currentTimeMillis();
 
 		System.out.println(String.format("Shutdown took %d milliseconds", after - before));
-		System.out.println(String.format("Greatest thread count: %d", testEPC.getGreatestActiveThreadCount()));
 
-		System.out.println(String.format("Tasks produced: %d", testEPC.getTasksProduced()));
+		StatsSnapshot snapshot = testEPC.getStatsSnapshot();
-		System.out.println(String.format("Tasks consumed: %d", testEPC.getTasksConsumed()));
+		System.out.println(String.format("Greatest thread count: %d, tasks produced: %d, tasks consumed: %d",
+				snapshot.greatestActiveThreadCount, snapshot.tasksProduced, snapshot.tasksConsumed));
 	}
 
 	@Test