Reinstate time-to-first-byte-ms metric.

components/client/src/main/java/com/hotels/styx/client/Connection.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2019 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -65,13 +65,6 @@ interface Factory {
      */
     Origin getOrigin();
 
-    /**
-     * Returns time to first byte in milliseconds.
-     *
-     * @return time to first byte in milliseconds
-     */
-    long getTimeToFirstByteMillis();
-
     /**
      * Register a listener connection state events.
      *

components/client/src/main/java/com/hotels/styx/client/applications/AggregateTimer.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2018 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -48,21 +48,21 @@ public void stopAndRecord() {
         }
     }
 
-    private final Timer requestLatency;
-    private final Timer applicationLatency;
+    private final Timer requestTimer;
+    private final Timer applicationTimer;
 
     /**
      * Constructor.
      *
-     * @param requestLatency a timer
-     * @param applicationLatency a timer
+     * @param requestTimer a timer
+     * @param applicationTimer a timer
      */
-    public AggregateTimer(Timer requestLatency, Timer applicationLatency) {
-        this.requestLatency = requestLatency;
-        this.applicationLatency = applicationLatency;
+    public AggregateTimer(Timer requestTimer, Timer applicationTimer) {
+        this.requestTimer = requestTimer;
+        this.applicationTimer = applicationTimer;
     }
 
     public Stopper time() {
-        return new Stopper(requestLatency.time(), applicationLatency.time());
+        return new Stopper(requestTimer.time(), applicationTimer.time());
     }
 }

components/client/src/main/java/com/hotels/styx/client/applications/OriginStats.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2018 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -33,10 +33,15 @@ public interface OriginStats {
     void requestError();
 
     /**
-     * Starts request latency timer.
+     * Returns a request latency timer.
      */
     AggregateTimer requestLatencyTimer();
 
+    /**
+     * Returns a time-to-first-byte timer.
+     */
+    AggregateTimer timeToFirstByteTimer();
+
     /**
      * records a response with a status code.
      *

components/client/src/main/java/com/hotels/styx/client/applications/metrics/ApplicationMetrics.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2018 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -32,6 +32,7 @@ public class ApplicationMetrics {
     private final MetricRegistry applicationMetrics;
     private final MetricRegistry requestScope;
     private final Timer requestLatencyTimer;
+    private final Timer requestTimeToFirstByteTimer;
     private final Meter requestSuccessMeter;
     private final Meter requestErrorMeter;
     private final Meter status200OkMeter;
@@ -52,6 +53,7 @@ public ApplicationMetrics(Id appId, MetricRegistry metricRegistry) {
 
         this.requestScope = this.applicationMetrics.scope("requests");
         this.requestLatencyTimer = this.requestScope.timer("latency");
+        this.requestTimeToFirstByteTimer = this.requestScope.timer("time-to-first-byte");
         this.requestSuccessMeter = this.requestScope.meter("success-rate");
         this.requestErrorMeter = this.requestScope.meter("error-rate");
         this.status200OkMeter = this.requestScope.meter(name("response", statusCodeName(200)));
@@ -73,14 +75,19 @@ public void requestError() {
     }
 
     /**
-     * Starts request latency timer.
-     *
-     * @return timer context for request latency
+     * Returns request latency timer.
      */
     public Timer requestLatencyTimer() {
         return requestLatencyTimer;
     }
 
+    /**
+     * Returns request time-to-first-byte timer.
+     */
+    public Timer requestTimeToFirstByteTimer() {
+        return requestTimeToFirstByteTimer;
+    }
+
     /**
      * Returns the metrics registry used.
      *

components/client/src/main/java/com/hotels/styx/client/applications/metrics/OriginMetrics.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2019 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -50,6 +50,7 @@ public class OriginMetrics implements OriginStats {
     private final Meter requestSuccessMeter;
     private final Meter requestErrorMeter;
     private final Timer requestLatency;
+    private final Timer timeToFirstByte;
     private final Meter status200OkMeter;
     private final Meter errorsCatchAll;
 
@@ -60,7 +61,7 @@ public class OriginMetrics implements OriginStats {
      * Constructor.
      *
      * @param applicationMetrics application metrics
-     * @param origin             an origin
+     * @param originId           an origin
      */
     public OriginMetrics(ApplicationMetrics applicationMetrics, String originId) {
         this.applicationMetrics = requireNonNull(applicationMetrics);
@@ -72,6 +73,7 @@ public OriginMetrics(ApplicationMetrics applicationMetrics, String originId) {
         this.requestSuccessMeter = this.registry.meter(name(this.requestMetricPrefix, "success-rate"));
         this.requestErrorMeter = this.registry.meter(name(this.requestMetricPrefix, "error-rate"));
         this.requestLatency = this.registry.timer(name(this.requestMetricPrefix, "latency"));
+        this.timeToFirstByte = this.registry.timer(name(this.requestMetricPrefix, "time-to-first-byte"));
         this.status200OkMeter = this.registry.meter(name(this.requestMetricPrefix, "response", statusCodeName(200)));
         this.errorsCatchAll = this.registry.meter(name(this.requestMetricPrefix, "response.status.5xx"));
 
@@ -81,7 +83,8 @@ public OriginMetrics(ApplicationMetrics applicationMetrics, String originId) {
     /**
      * Create a new OriginMetrics.
      *
-     * @param origin         an origin
+     * @param appId          application ID
+     * @param originId       an origin
      * @param metricRegistry a metrics registry
      * @return a new OriginMetrics
      */
@@ -134,6 +137,11 @@ public AggregateTimer requestLatencyTimer() {
         return new AggregateTimer(requestLatency, applicationMetrics.requestLatencyTimer());
     }
 
+    @Override
+    public AggregateTimer timeToFirstByteTimer() {
+        return new AggregateTimer(timeToFirstByte, applicationMetrics.requestTimeToFirstByteTimer());
+    }
+
     private int httpStatusCodeClass(int code) {
         if (code < 100 || code >= 600) {
             return 0;

components/client/src/main/java/com/hotels/styx/client/connectionpool/ConnectionPool.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2019 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.

components/client/src/main/java/com/hotels/styx/client/connectionpool/ExpiringConnection.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2019 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -62,11 +62,6 @@ public Origin getOrigin() {
         return nettyConnection.getOrigin();
     }
 
-    @Override
-    public long getTimeToFirstByteMillis() {
-        return nettyConnection.getTimeToFirstByteMillis();
-    }
-
     @Override
     public void addConnectionListener(Listener listener) {
         nettyConnection.addConnectionListener(listener);

components/client/src/main/java/com/hotels/styx/client/connectionpool/SimpleConnectionPool.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2019 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -223,6 +223,7 @@ public ConnectionPool.Stats stats() {
 
     @VisibleForTesting
     private class ConnectionPoolStats implements Stats {
+
         @Override
         public int availableConnectionCount() {
             return availableConnections.size();
@@ -263,7 +264,6 @@ public int connectionsInEstablishment() {
             return connectionsInEstablishment.get();
         }
 
-
         @Override
         public String toString() {
             return MoreObjects.toStringHelper(this)

components/client/src/main/java/com/hotels/styx/client/connectionpool/StatsReportingConnectionPool.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2019 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.

components/client/src/main/java/com/hotels/styx/client/connectionpool/stubs/StubConnectionFactory.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2019 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -64,11 +64,6 @@ public Origin getOrigin() {
             return this.origin;
         }
 
-        @Override
-        public long getTimeToFirstByteMillis() {
-            return 0;
-        }
-
         @Override
         public void addConnectionListener(Listener listener) {
             listeners.addListener(listener);

components/client/src/main/java/com/hotels/styx/client/netty/connectionpool/NettyConnection.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2019 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -32,23 +32,21 @@
 import reactor.core.publisher.Flux;
 
 import java.util.Optional;
-import java.util.concurrent.TimeUnit;
 
 import static com.google.common.base.Objects.toStringHelper;
 import static java.util.Objects.requireNonNull;
 
 /**
  * A connection using a netty channel.
  */
-public class NettyConnection implements Connection, TimeToFirstByteListener {
+public class NettyConnection implements Connection {
     private static final AttributeKey<Object> CLOSED_BY_STYX = AttributeKey.newInstance("CLOSED_BY_STYX");
     private static final int IGNORED_PORT_NUMBER = -1;
 
     private final Origin origin;
     private final Channel channel;
     private final HttpRequestOperationFactory requestOperationFactory;
 
-    private volatile long timeToFirstByteMs;
     private final Announcer<Listener> listeners = Announcer.to(Listener.class);
 
 
@@ -68,7 +66,6 @@ public NettyConnection(Origin origin, Channel channel, HttpRequestOperationFacto
         this.origin = requireNonNull(origin);
         this.channel = requireNonNull(channel);
         this.requestOperationFactory = requestOperationFactory;
-        this.channel.pipeline().addLast(new TimeToFirstByteHandler(this));
         this.channel.closeFuture().addListener(future ->
                 listeners.announce().connectionClosed(NettyConnection.this));
         addChannelHandlers(channel, httpConfig, sslContext, sendSni, sniHost.orElse(origin.host()));
@@ -115,11 +112,6 @@ public Origin getOrigin() {
         return this.origin;
     }
 
-    @Override
-    public long getTimeToFirstByteMillis() {
-        return this.timeToFirstByteMs;
-    }
-
     @Override
     public void addConnectionListener(Listener listener) {
         this.listeners.addListener(listener);
@@ -133,11 +125,6 @@ public void close() {
         }
     }
 
-    @Override
-    public void notifyTimeToFirstByte(long timeToFirstByte, TimeUnit timeUnit) {
-        this.timeToFirstByteMs = timeUnit.toMillis(timeToFirstByte);
-    }
-
     @Override
     public String toString() {
         return toStringHelper(this)

components/client/src/main/java/com/hotels/styx/client/netty/connectionpool/RequestsToOriginMetricsCollector.java

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2013-2018 Expedia Inc.
+  Copyright (C) 2013-2020 Expedia Inc.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@
 import io.netty.channel.ChannelDuplexHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelPromise;
+import io.netty.handler.codec.http.HttpContent;
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.handler.codec.http.LastHttpContent;
 import org.slf4j.Logger;
@@ -38,6 +39,9 @@ class RequestsToOriginMetricsCollector extends ChannelDuplexHandler {
 
     private final OriginStats originStats;
     private volatile AggregateTimer.Stopper requestLatencyTiming;
+    private volatile AggregateTimer.Stopper timeToFirstByteTiming;
+    private volatile boolean firstContentChunkReceived;
+
 
     /**
      * Constructs a new instance.
@@ -62,6 +66,11 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
             updateHttpResponseCounters(code);
         }
 
+        if (msg instanceof HttpContent && !firstContentChunkReceived) {
+            stopAndRecordTimeToFirstByte();
+            firstContentChunkReceived = true;
+        }
+
         if (msg instanceof LastHttpContent) {
             stopAndRecordLatency();
         }
@@ -73,6 +82,8 @@ public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception
     public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
         if (msg instanceof io.netty.handler.codec.http.HttpRequest) {
             requestLatencyTiming = originStats.requestLatencyTimer().time();
+            timeToFirstByteTiming = originStats.timeToFirstByteTimer().time();
+            firstContentChunkReceived = false;
         }
         super.write(ctx, msg, promise);
     }
@@ -93,6 +104,7 @@ private void updateHttpResponseCounters(int statusCode) {
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
         stopAndRecordLatency();
+        stopAndRecordTimeToFirstByte();
         super.exceptionCaught(ctx, cause);
     }
 
@@ -106,4 +118,12 @@ private void stopAndRecordLatency() {
             LOG.warn("Attempted to stop timer and record latency when no timing had begun");
         }
     }
+
+    private void stopAndRecordTimeToFirstByte() {
+        if (timeToFirstByteTiming != null) {
+            timeToFirstByteTiming.stopAndRecord();
+        } else {
+            LOG.warn("Attempted to stop timer and record time-to-first-byte when no timing had begun");
+        }
+    }
 }