ARTEMIS-5320 expose session count metrics

artemis-commons/src/main/java/org/apache/activemq/artemis/logs/AuditLogger.java

@@ -2839,12 +2839,24 @@ static void getPrefetchPageMessages(Object source) {
    @LogMessage(id = 601794, value = "User {} is getting prefetchPageMessages on target resource: {}", level = LogMessage.Level.INFO)
    void getPrefetchPageMessages(String user, Object source);
 
-
    static void getPrefetchPageBytes(Object source) {
       BASE_LOGGER.getPrefetchPageBytes(getCaller(), source);
    }
 
    @LogMessage(id = 601795, value = "User {} is getting prefetchPageBytes on target resource: {}", level = LogMessage.Level.INFO)
    void getPrefetchPageBytes(String user, Object source);
 
+   static void getSessionCount(Object source, Object... args) {
+      BASE_LOGGER.getSessionCount(getCaller(), source, parametersList(args));
+   }
+
+   @LogMessage(id = 601796, value = "User {} is getting session count on target resource: {} {}", level = LogMessage.Level.INFO)
+   void getSessionCount(String user, Object source, String args);
+
+   static void getTotalSessionCount(Object source) {
+      BASE_LOGGER.getTotalSessionCount(getCaller(), source);
+   }
+
+   @LogMessage(id = 601797, value = "User {} is getting total session count on target resource: {}", level = LogMessage.Level.INFO)
+   void getTotalSessionCount(String user, Object source);
 }

artemis-core-client/src/main/java/org/apache/activemq/artemis/api/core/management/ActiveMQServerControl.java

@@ -27,7 +27,9 @@
  */
 public interface ActiveMQServerControl {
    String CONNECTION_COUNT_DESCRIPTION = "Number of clients connected to this server";
-   String TOTAL_CONNECTION_COUNT_DESCRIPTION = "Number of clients which have connected to this server since it was started";
+   String TOTAL_CONNECTION_COUNT_DESCRIPTION = "Total number of clients which have connected to this server since it was started";
+   String SESSION_COUNT_DESCRIPTION = "Number of sessions on this server";
+   String TOTAL_SESSION_COUNT_DESCRIPTION = "Total number of sessions created on this server since it was started";
    String ADDRESS_MEMORY_USAGE_DESCRIPTION = "Memory used by all the addresses on broker for in-memory messages";
    String ADDRESS_MEMORY_USAGE_PERCENTAGE_DESCRIPTION = "Memory used by all the addresses on broker as a percentage of the global-max-size";
    String DISK_STORE_USAGE_DESCRIPTION = "Fraction of total disk store used";
@@ -64,11 +66,23 @@ public interface ActiveMQServerControl {
    int getConnectionCount();
 
    /**
-    * {@return the number of clients which have connected to this server since it was started.}
+    * {@return the total number of clients which have connected to this server since it was started.}
     */
    @Attribute(desc = TOTAL_CONNECTION_COUNT_DESCRIPTION)
    long getTotalConnectionCount();
 
+   /**
+    * Returns the number of sessions on this server.
+    */
+   @Attribute(desc = SESSION_COUNT_DESCRIPTION)
+   int getSessionCount();
+
+   /**
+    * Returns the total number of sessions created on this server since it was started.
+    */
+   @Attribute(desc = TOTAL_SESSION_COUNT_DESCRIPTION)
+   long getTotalSessionCount();
+
    /**
     * {@return the number of messages in all queues currently on the server.}
     */

artemis-server/src/main/java/org/apache/activemq/artemis/core/management/impl/ActiveMQServerControlImpl.java

@@ -1731,6 +1731,36 @@ public long getTotalConnectionCount() {
       }
    }
 
+   @Override
+   public int getSessionCount() {
+      if (AuditLogger.isBaseLoggingEnabled()) {
+         AuditLogger.getSessionCount(this.server);
+      }
+      checkStarted();
+
+      clearIO();
+      try {
+         return server.getSessionCount();
+      } finally {
+         blockOnIO();
+      }
+   }
+
+   @Override
+   public long getTotalSessionCount() {
+      if (AuditLogger.isBaseLoggingEnabled()) {
+         AuditLogger.getTotalSessionCount(this.server);
+      }
+      checkStarted();
+
+      clearIO();
+      try {
+         return server.getTotalSessionCount();
+      } finally {
+         blockOnIO();
+      }
+   }
+
    @Override
    public long getTotalMessageCount() {
       if (AuditLogger.isBaseLoggingEnabled()) {

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/ActiveMQServer.java

@@ -420,6 +420,10 @@ ServerSession createInternalSession(String name,
 
    long getTotalConnectionCount();
 
+   int getSessionCount();
+
+   long getTotalSessionCount();
+
    long getTotalMessageCount();
 
    long getTotalMessagesAdded();

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/ActiveMQServerImpl.java

@@ -52,6 +52,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Consumer;
 import java.util.function.Supplier;
@@ -349,6 +350,8 @@ public class ActiveMQServerImpl implements ActiveMQServer {
 
    private final ConcurrentMap<String, ServerSession> sessions = new ConcurrentHashMap<>();
 
+   private AtomicLong totalSessionCount = new AtomicLong(0);
+
    private final Semaphore activationLock = new Semaphore(1);
    /**
     * This class here has the same principle of CountDownLatch but you can reuse the counters.
@@ -1866,6 +1869,7 @@ protected ServerSessionImpl internalCreateSession(String name,
       ServerSessionImpl session = new ServerSessionImpl(name, username, password, validatedUser, minLargeMessageSize, autoCommitSends, autoCommitAcks, preAcknowledge, configuration.isPersistDeliveryCountBeforeDelivery(), xa, connection, storageManager, postOffice, resourceManager, securityStore, managementService, this, configuration.getManagementAddress(), defaultAddress == null ? null : SimpleString.of(defaultAddress), callback, context, pagingManager, prefixes, securityDomain, isLegacyProducer);
 
       sessions.put(name, session);
+      totalSessionCount.incrementAndGet();
 
       if (hasBrokerSessionPlugins()) {
          callBrokerSessionPlugins(plugin -> plugin.afterCreateSession(session));
@@ -1942,6 +1946,16 @@ public long getTotalConnectionCount() {
       return remotingService.getTotalConnectionCount();
    }
 
+   @Override
+   public int getSessionCount() {
+      return sessions.size();
+   }
+
+   @Override
+   public long getTotalSessionCount() {
+      return totalSessionCount.get();
+   }
+
    @Override
    public long getTotalMessageCount() {
       long total = 0;

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/management/impl/ManagementServiceImpl.java

@@ -248,6 +248,8 @@ private void registerBrokerMeters() {
          metricsManager.registerBrokerGauge(builder -> {
             builder.build(BrokerMetricNames.CONNECTION_COUNT, messagingServer, metrics -> (double) messagingServer.getConnectionCount(), ActiveMQServerControl.CONNECTION_COUNT_DESCRIPTION, Collections.emptyList());
             builder.build(BrokerMetricNames.TOTAL_CONNECTION_COUNT, messagingServer, metrics -> (double) messagingServer.getTotalConnectionCount(), ActiveMQServerControl.TOTAL_CONNECTION_COUNT_DESCRIPTION, Collections.emptyList());
+            builder.build(BrokerMetricNames.SESSION_COUNT, messagingServer, metrics -> (double) messagingServer.getSessionCount(), ActiveMQServerControl.SESSION_COUNT_DESCRIPTION, Collections.emptyList());
+            builder.build(BrokerMetricNames.TOTAL_SESSION_COUNT, messagingServer, metrics -> (double) messagingServer.getTotalSessionCount(), ActiveMQServerControl.TOTAL_SESSION_COUNT_DESCRIPTION, Collections.emptyList());
             builder.build(BrokerMetricNames.ADDRESS_MEMORY_USAGE, messagingServer, metrics -> (double) messagingServerControl.getAddressMemoryUsage(), ActiveMQServerControl.ADDRESS_MEMORY_USAGE_DESCRIPTION, Collections.emptyList());
             builder.build(BrokerMetricNames.ADDRESS_MEMORY_USAGE_PERCENTAGE, messagingServer, metrics -> (double) messagingServerControl.getAddressMemoryUsagePercentage(), ActiveMQServerControl.ADDRESS_MEMORY_USAGE_PERCENTAGE_DESCRIPTION, Collections.emptyList());
             builder.build(BrokerMetricNames.DISK_STORE_USAGE, messagingServer, metrics -> messagingServer.getDiskStoreUsage(), ActiveMQServerControl.DISK_STORE_USAGE_DESCRIPTION, Collections.emptyList());

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/metrics/BrokerMetricNames.java

@@ -20,6 +20,8 @@ public class BrokerMetricNames {
 
    public static final String CONNECTION_COUNT = "connection.count";
    public static final String TOTAL_CONNECTION_COUNT = "total.connection.count";
+   public static final String SESSION_COUNT = "session.count";
+   public static final String TOTAL_SESSION_COUNT = "total.session.count";
    public static final String ADDRESS_MEMORY_USAGE = "address.memory.usage";
    public static final String ADDRESS_MEMORY_USAGE_PERCENTAGE = "address.memory.usage.percentage";
    public static final String DISK_STORE_USAGE = "disk.store.usage";

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/management/ActiveMQServerControlTest.java

@@ -2520,7 +2520,7 @@ public void testTotalMessageCount() throws Exception {
    }
 
    @TestTemplate
-   public void testTotalConnectionCount() throws Exception {
+   public void testConnectionCounts() throws Exception {
       final int CONNECTION_COUNT = 100;
 
       ActiveMQServerControl serverControl = createManagementControl();
@@ -2536,6 +2536,37 @@ public void testTotalConnectionCount() throws Exception {
       locator.close();
    }
 
+   @TestTemplate
+   public void testSessionCounts() throws Exception {
+      // don't test this with management messages as it completely throws off the session counts
+      assumeFalse(usingCore());
+      final int SESSION_COUNT = 100;
+
+      ActiveMQServerControl serverControl = createManagementControl();
+      ServerLocator locator = createInVMNonHALocator();
+      ClientSessionFactory csf = createSessionFactory(locator);
+      List<ClientSession> sessions = new ArrayList<>(SESSION_COUNT);
+
+      assertEquals(0, serverControl.getSessionCount());
+
+      for (int i = 1; i <= SESSION_COUNT; i++) {
+         sessions.add(csf.createSession());
+         assertEquals(i, serverControl.getSessionCount());
+      }
+
+      assertEquals(SESSION_COUNT, serverControl.getTotalSessionCount());
+
+      for (int i = 1; i <= SESSION_COUNT; i++) {
+         sessions.get(i - 1).close();
+         assertEquals(SESSION_COUNT - i, serverControl.getSessionCount());
+      }
+
+      assertEquals(SESSION_COUNT, serverControl.getTotalSessionCount());
+      assertEquals(0, serverControl.getSessionCount());
+
+      locator.close();
+   }
+
    @TestTemplate
    public void testTotalMessagesAdded() throws Exception {
       String random1 = RandomUtil.randomUUIDString();

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/management/ActiveMQServerControlUsingCoreTest.java

@@ -401,6 +401,16 @@ public long getTotalConnectionCount() {
             return (Long) proxy.retrieveAttributeValue("totalConnectionCount", Long.class);
          }
 
+         @Override
+         public int getSessionCount() {
+            return (Integer) proxy.retrieveAttributeValue("sessionCount", Integer.class);
+         }
+
+         @Override
+         public long getTotalSessionCount() {
+            return (Long) proxy.retrieveAttributeValue("totalSessionCount", Long.class);
+         }
+
          @Override
          public long getTotalMessageCount() {
             return (Long) proxy.retrieveAttributeValue("totalMessageCount", Long.class);

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/plugin/MetricsPluginTest.java

@@ -140,6 +140,8 @@ public int hashCode() {
               new Metric("artemis.address.memory.usage.percentage", 0.0, Arrays.asList(Tag.of("broker", "localhost"))),
               new Metric("artemis.connection.count", 1.0, Arrays.asList(Tag.of("broker", "localhost"))),
               new Metric("artemis.total.connection.count", 1.0, Arrays.asList(Tag.of("broker", "localhost"))),
+              new Metric("artemis.session.count", 1.0, Arrays.asList(Tag.of("broker", "localhost"))),
+              new Metric("artemis.total.session.count", 1.0, Arrays.asList(Tag.of("broker", "localhost"))),
               new Metric("artemis.active", 1.0, Arrays.asList(Tag.of("broker", "localhost"))),
               new Metric("artemis.replica.sync", 0.0, Arrays.asList(Tag.of("broker", "localhost"))),
               new Metric("artemis.disk.store.usage", 0.0, Arrays.asList(Tag.of("broker", "localhost"))),