Add pendingResponse to ServerMetrics

Author: warmth424

core/src/main/java/com/linecorp/armeria/server/GracefulShutdownSupport.java

@@ -19,7 +19,6 @@
 import java.time.Duration;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.atomic.LongAdder;
 
 import com.google.common.base.Ticker;
 
@@ -29,39 +28,48 @@
  */
 abstract class GracefulShutdownSupport {
 
-    static GracefulShutdownSupport create(Duration quietPeriod, Executor blockingTaskExecutor) {
-        return create(quietPeriod, blockingTaskExecutor, Ticker.systemTicker());
+    private final ServerMetrics serverMetrics;
+
+    /**
+     * Creates a new instance.
+     */
+    GracefulShutdownSupport(ServerMetrics serverMetrics) {
+        this.serverMetrics = serverMetrics;
     }
 
-    static GracefulShutdownSupport create(Duration quietPeriod, Executor blockingTaskExecutor, Ticker ticker) {
-        return new DefaultGracefulShutdownSupport(quietPeriod, blockingTaskExecutor, ticker);
+    static GracefulShutdownSupport create(Duration quietPeriod, Executor blockingTaskExecutor,
+                                          ServerMetrics serverMetrics) {
+        return create(quietPeriod, blockingTaskExecutor, Ticker.systemTicker(), serverMetrics);
     }
 
-    static GracefulShutdownSupport createDisabled() {
-        return new DisabledGracefulShutdownSupport();
+    static GracefulShutdownSupport create(Duration quietPeriod, Executor blockingTaskExecutor, Ticker ticker,
+                                          ServerMetrics serverMetrics) {
+        return new DefaultGracefulShutdownSupport(quietPeriod, blockingTaskExecutor, ticker, serverMetrics);
     }
 
-    private final LongAdder pendingResponses = new LongAdder();
+    static GracefulShutdownSupport createDisabled(ServerMetrics serverMetrics) {
+        return new DisabledGracefulShutdownSupport(serverMetrics);
+    }
 
     /**
      * Increases the number of pending responses.
      */
     final void inc() {
-        pendingResponses.increment();
+        serverMetrics.increaseNonTransientRequests();
     }
 
     /**
      * Decreases the number of pending responses.
      */
     void dec() {
-        pendingResponses.decrement();
+        serverMetrics.decreaseNonTransientRequests();
     }
 
     /**
      * Returns the number of pending responses.
      */
-    final long pendingResponses() {
-        return pendingResponses.sum();
+    final long activeNonTransientResponses() {
+        return serverMetrics.activeNonTransientRequests();
     }
 
     /**
@@ -78,6 +86,14 @@ private static final class DisabledGracefulShutdownSupport extends GracefulShutd
 
         private volatile boolean shuttingDown;
 
+        /**
+         * Creates a new instance.
+         *
+         */
+        DisabledGracefulShutdownSupport(ServerMetrics serverMetrics) {
+            super(serverMetrics);
+        }
+
         @Override
         boolean isShuttingDown() {
             return shuttingDown;
@@ -97,12 +113,14 @@ private static final class DefaultGracefulShutdownSupport extends GracefulShutdo
         private final Executor blockingTaskExecutor;
 
         /**
-         * Declared as non-volatile because using {@link #pendingResponses} as a memory barrier.
+         * Declared as non-volatile because using {@link #activeNonTransientResponses} as a memory barrier.
          */
         private long lastResTimeNanos;
         private volatile long shutdownStartTimeNanos;
 
-        DefaultGracefulShutdownSupport(Duration quietPeriod, Executor blockingTaskExecutor, Ticker ticker) {
+        DefaultGracefulShutdownSupport(Duration quietPeriod, Executor blockingTaskExecutor, Ticker ticker,
+                                       ServerMetrics serverMetrics) {
+            super(serverMetrics);
             quietPeriodNanos = quietPeriod.toNanos();
             this.blockingTaskExecutor = blockingTaskExecutor;
             this.ticker = ticker;
@@ -125,7 +143,7 @@ boolean completedQuietPeriod() {
                 shutdownStartTimeNanos = readTicker();
             }
 
-            if (pendingResponses() != 0 || !completedBlockingTasks()) {
+            if (activeNonTransientResponses() != 0 || !completedBlockingTasks()) {
                 return false;
             }
 

core/src/main/java/com/linecorp/armeria/server/Server.java

@@ -502,11 +502,11 @@ private final class ServerStartStopSupport extends StartStopSupport<Void, Void,
         @Override
         protected CompletionStage<Void> doStart(@Nullable Void arg) {
             if (config().gracefulShutdownQuietPeriod().isZero()) {
-                gracefulShutdownSupport = GracefulShutdownSupport.createDisabled();
+                gracefulShutdownSupport = GracefulShutdownSupport.createDisabled(config.serverMetrics());
             } else {
                 gracefulShutdownSupport =
                         GracefulShutdownSupport.create(config().gracefulShutdownQuietPeriod(),
-                                                       config().blockingTaskExecutor());
+                                                       config().blockingTaskExecutor(), config.serverMetrics());
             }
 
             // Initialize the server sockets asynchronously.
@@ -585,8 +585,6 @@ private void setupServerMetrics() {
             final GracefulShutdownSupport gracefulShutdownSupport = this.gracefulShutdownSupport;
             assert gracefulShutdownSupport != null;
 
-            meterRegistry.gauge("armeria.server.pending.responses", gracefulShutdownSupport,
-                                GracefulShutdownSupport::pendingResponses);
             config.serverMetrics().bindTo(meterRegistry);
         }
 

core/src/main/java/com/linecorp/armeria/server/ServerMetrics.java

@@ -39,6 +39,7 @@ public final class ServerMetrics implements MeterBinder {
     private final LongAdder activeHttp1WebSocketRequests = new LongAdder();
     private final LongAdder activeHttp1Requests = new LongAdder();
     private final LongAdder activeHttp2Requests = new LongAdder();
+    private final LongAdder activeNonTransientRequests = new LongAdder();
 
     /**
      * AtomicInteger is used to read the number of active connections frequently.
@@ -98,6 +99,13 @@ public long activeHttp2Requests() {
         return activeHttp2Requests.longValue();
     }
 
+    /**
+     * Returns the number of pending http responses.
+     */
+    public long activeNonTransientRequests() {
+        return activeNonTransientRequests.longValue();
+    }
+
     /**
      * Returns the number of open connections.
      */
@@ -153,6 +161,14 @@ void decreaseActiveConnections() {
         activeConnections.decrementAndGet();
     }
 
+    void increaseNonTransientRequests() {
+        activeNonTransientRequests.increment();
+    }
+
+    void decreaseNonTransientRequests() {
+        activeNonTransientRequests.decrement();
+    }
+
     @Override
     public void bindTo(MeterRegistry meterRegistry) {
         meterRegistry.gauge("armeria.server.connections", activeConnections);
@@ -174,6 +190,10 @@ public void bindTo(MeterRegistry meterRegistry) {
         meterRegistry.gauge(allRequestsMeterName,
                             ImmutableList.of(Tag.of("protocol", "http1.websocket"), Tag.of("state", "active")),
                             activeHttp1WebSocketRequests);
+        // pending non-transient responses
+        meterRegistry.gauge(allRequestsMeterName,
+                            ImmutableList.of(Tag.of("protocol", "all"), Tag.of("state", "active")),
+                activeNonTransientRequests);
     }
 
     @Override
@@ -185,6 +205,7 @@ public String toString() {
                           .add("pendingHttp2Requests", pendingHttp2Requests)
                           .add("activeHttp2Requests", activeHttp2Requests)
                           .add("activeConnections", activeConnections)
+                          .add("activeNonTransientRequests", activeNonTransientRequests)
                           .toString();
     }
 }

core/src/test/java/com/linecorp/armeria/server/GracefulShutdownSupportTest.java

@@ -45,6 +45,8 @@ class GracefulShutdownSupportTest {
     @Mock
     private Ticker ticker;
 
+    private ServerMetrics serverMetrics;
+
     private GracefulShutdownSupport support;
     private ThreadPoolExecutor executor;
 
@@ -54,7 +56,9 @@ void setUp() {
                 0, 1, 1, TimeUnit.SECONDS, new LinkedTransferQueue<>(),
                 ThreadFactories.newThreadFactory("graceful-shutdown-test", true));
 
-        support = GracefulShutdownSupport.create(Duration.ofNanos(QUIET_PERIOD_NANOS), executor, ticker);
+        serverMetrics = new ServerMetrics();
+        support = GracefulShutdownSupport.create(Duration.ofNanos(QUIET_PERIOD_NANOS), executor, ticker,
+                                                 serverMetrics);
     }
 
     @AfterEach
@@ -64,17 +68,17 @@ void tearDown() {
 
     @Test
     void testDisabled() {
-        final GracefulShutdownSupport support = GracefulShutdownSupport.createDisabled();
+        final GracefulShutdownSupport support = GracefulShutdownSupport.createDisabled(serverMetrics);
         assertThat(support.isShuttingDown()).isFalse();
         assertThat(support.completedQuietPeriod()).isTrue();
         assertThat(support.isShuttingDown()).isTrue();
         support.inc();
-        assertThat(support.pendingResponses()).isOne();
+        assertThat(support.activeNonTransientResponses()).isOne();
         assertThat(support.completedQuietPeriod()).isTrue();
 
         // pendingResponses must be updated even if disabled, because it's part of metrics.
         support.dec();
-        assertThat(support.pendingResponses()).isZero();
+        assertThat(support.activeNonTransientResponses()).isZero();
     }
 
     @Test