[DE-82] Feature/overload-control (#419)

* CircularFifoQueue

* CircularFifoQueue.getAvg()

* created QueueTimeMetrics interfaces

* queue time metrics tests

* queue time metrics config

* faster queue time metrics tests

* fixed gh actions artifact upload

* fixed gh actions artifact upload

* fixed gh actions artifact upload

* "X-Arango-Queue-Time-Seconds" header set in requests

Author: rashtao

.github/workflows/maven.yml

@@ -83,7 +83,7 @@ jobs:
         if: ${{ cancelled() || failure() }}
         uses: actions/upload-artifact@master
         with:
-          name: logs.tgz
+          name: logs-${{github.job}}.tgz
           path: ./logs.tgz
 
   # test encodeURIComponent() and normalize('NFC') comparing to Javascript behavior

src/main/java/com/arangodb/ArangoDB.java

@@ -326,6 +326,17 @@ public Builder loadBalancingStrategy(final LoadBalancingStrategy loadBalancingSt
             return this;
         }
 
+        /**
+         * Setting the amount of samples kept for queue time metrics
+         *
+         * @param responseQueueTimeSamples amount of samples to keep
+         * @return {@link ArangoDB.Builder}
+         */
+        public Builder responseQueueTimeSamples(final Integer responseQueueTimeSamples) {
+            setResponseQueueTimeSamples(responseQueueTimeSamples);
+            return this;
+        }
+
         /**
          * Register a custom {@link VPackSerializer} for a specific type to be used within the internal serialization
          * process.
@@ -658,7 +669,8 @@ public synchronized ArangoDB build() {
                     protocol,
                     hostResolver,
                     hostHandler,
-                    new ArangoContext());
+                    new ArangoContext(),
+                    responseQueueTimeSamples, timeout);
         }
 
     }
@@ -705,6 +717,11 @@ default ArangoDatabase db(String name) {
      */
     ArangoDatabase db(DbName dbName);
 
+    /**
+     * @return entry point for accessing client metrics
+     */
+    ArangoMetrics metrics();
+
     /**
      * Creates a new database with the given name.
      *

src/main/java/com/arangodb/ArangoMetrics.java

@@ -0,0 +1,34 @@
+/*
+ * DISCLAIMER
+ *
+ * Copyright 2016 ArangoDB GmbH, Cologne, Germany
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright holder is ArangoDB GmbH, Cologne, Germany
+ */
+
+package com.arangodb;
+
+/**
+ * Interface for accessing metrics.
+ *
+ * @author Michele Rastelli
+ * @since ArangoDB 3.9
+ */
+public interface ArangoMetrics {
+    /**
+     * @return queue time metrics
+     */
+    QueueTimeMetrics getQueueTime();
+}

src/main/java/com/arangodb/QueueTimeMetrics.java

@@ -0,0 +1,45 @@
+/*
+ * DISCLAIMER
+ *
+ * Copyright 2016 ArangoDB GmbH, Cologne, Germany
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright holder is ArangoDB GmbH, Cologne, Germany
+ */
+
+package com.arangodb;
+
+import com.arangodb.model.QueueTimeSample;
+
+/**
+ * Interface for accessing queue time latency metrics, reported by the "X-Arango-Queue-Time-Seconds" response header.
+ * This header contains the most recent request (de)queuing time (in seconds) as tracked by the server’s scheduler.
+ *
+ * @author Michele Rastelli
+ * @see <a href="https://www.arangodb.com/docs/stable/http/general.html#overload-control">API Documentation</a>
+ * @since ArangoDB 3.9
+ */
+public interface QueueTimeMetrics {
+
+    /**
+     * @return all the n values observed
+     */
+    QueueTimeSample[] getValues();
+
+    /**
+     * @return the average of the last n values observed, 0.0 if no value has been observed (i.e. in ArangoDB versions
+     * prior to 3.9).
+     */
+    double getAvg();
+}

src/main/java/com/arangodb/async/ArangoDBAsync.java

@@ -20,10 +20,7 @@
 
 package com.arangodb.async;
 
-import com.arangodb.ArangoDBException;
-import com.arangodb.ArangoSerializationAccessor;
-import com.arangodb.DbName;
-import com.arangodb.Protocol;
+import com.arangodb.*;
 import com.arangodb.async.internal.ArangoDBAsyncImpl;
 import com.arangodb.async.internal.velocystream.VstCommunicationAsync;
 import com.arangodb.async.internal.velocystream.VstConnectionFactoryAsync;
@@ -110,6 +107,11 @@ default ArangoDatabaseAsync db(final String name) {
      */
     ArangoDatabaseAsync db(final DbName dbName);
 
+    /**
+     * @return entry point for accessing client metrics
+     */
+    ArangoMetrics metrics();
+
     /**
      * Creates a new database
      *
@@ -497,6 +499,17 @@ public Builder acquireHostList(final Boolean acquireHostList) {
             return this;
         }
 
+        /**
+         * Setting the amount of samples kept for queue time metrics
+         *
+         * @param responseQueueTimeSamples amount of samples to keep
+         * @return {@link ArangoDBAsync.Builder}
+         */
+        public Builder responseQueueTimeSamples(final Integer responseQueueTimeSamples) {
+            setResponseQueueTimeSamples(responseQueueTimeSamples);
+            return this;
+        }
+
         /**
          * Sets the load balancing strategy to be used in an ArangoDB cluster setup.
          * In case of Active-Failover deployment set to {@link LoadBalancingStrategy#NONE} or not set at all, since that
@@ -838,7 +851,9 @@ public synchronized ArangoDBAsync build() {
                     syncHostResolver,
                     asyncHostHandler,
                     syncHostHandler,
-                    new ArangoContext());
+                    new ArangoContext(),
+                    responseQueueTimeSamples,
+                    timeout);
         }
 
         private VstCommunicationAsync.Builder asyncBuilder(final HostHandler hostHandler) {

src/main/java/com/arangodb/async/internal/ArangoDBAsyncImpl.java

@@ -21,6 +21,7 @@
 package com.arangodb.async.internal;
 
 import com.arangodb.ArangoDBException;
+import com.arangodb.ArangoMetrics;
 import com.arangodb.DbName;
 import com.arangodb.async.ArangoDBAsync;
 import com.arangodb.async.ArangoDatabaseAsync;
@@ -68,18 +69,22 @@ public ArangoDBAsyncImpl(
             final HostResolver syncHostResolver,
             final HostHandler asyncHostHandler,
             final HostHandler syncHostHandler,
-            final ArangoContext context
+            final ArangoContext context,
+            final int responseQueueTimeSamples,
+            final int timeoutMs
     ) {
 
-        super(new ArangoExecutorAsync(asyncCommBuilder.build(util.get(Serializer.INTERNAL)), util, new DocumentCache()), util, context);
+        super(new ArangoExecutorAsync(asyncCommBuilder.build(util.get(Serializer.INTERNAL)), util, new DocumentCache(),
+                new QueueTimeMetricsImpl(responseQueueTimeSamples), timeoutMs), util, context);
 
         final VstCommunication<Response, VstConnectionSync> cacheCom = syncCommBuilder.build(util.get(Serializer.INTERNAL));
 
         cp = new VstProtocol(cacheCom);
         this.asyncHostHandler = asyncHostHandler;
         this.syncHostHandler = syncHostHandler;
 
-        ArangoExecutorSync arangoExecutorSync = new ArangoExecutorSync(cp, util, new DocumentCache());
+        ArangoExecutorSync arangoExecutorSync = new ArangoExecutorSync(cp, util, new DocumentCache(),
+                new QueueTimeMetricsImpl(responseQueueTimeSamples), timeoutMs);
         asyncHostResolver.init(arangoExecutorSync, util.get(Serializer.INTERNAL));
         syncHostResolver.init(arangoExecutorSync, util.get(Serializer.INTERNAL));
 
@@ -121,6 +126,11 @@ public ArangoDatabaseAsync db(final DbName name) {
         return new ArangoDatabaseAsyncImpl(this, name);
     }
 
+    @Override
+    public ArangoMetrics metrics() {
+        return new ArangoMetricsImpl(executor.getQueueTimeMetrics());
+    }
+
     @Override
     public CompletableFuture<Boolean> createDatabase(final DbName name) {
         return createDatabase(new DBCreateOptions().name(name));

src/main/java/com/arangodb/async/internal/ArangoExecutorAsync.java

@@ -24,6 +24,7 @@
 import com.arangodb.async.internal.velocystream.VstCommunicationAsync;
 import com.arangodb.internal.ArangoExecutor;
 import com.arangodb.internal.DocumentCache;
+import com.arangodb.internal.QueueTimeMetricsImpl;
 import com.arangodb.internal.net.HostHandle;
 import com.arangodb.internal.util.ArangoSerializationFactory;
 import com.arangodb.velocystream.Request;
@@ -44,8 +45,8 @@ public class ArangoExecutorAsync extends ArangoExecutor {
     private final ExecutorService outgoingExecutor = Executors.newSingleThreadExecutor();
 
     public ArangoExecutorAsync(final VstCommunicationAsync communication, final ArangoSerializationFactory util,
-                               final DocumentCache documentCache) {
-        super(util, documentCache);
+                               final DocumentCache documentCache, final QueueTimeMetricsImpl qtMetrics, final int timeoutMs) {
+        super(util, documentCache, qtMetrics, timeoutMs);
         this.communication = communication;
     }
 
@@ -67,8 +68,11 @@ private <T> CompletableFuture<T> execute(
             final HostHandle hostHandle) {
 
         return CompletableFuture.completedFuture(null)
-                .thenComposeAsync((it) -> communication.execute(request, hostHandle), outgoingExecutor)
-                .thenApplyAsync(responseDeserializer::deserialize);
+                .thenComposeAsync((it) -> communication.execute(interceptRequest(request), hostHandle), outgoingExecutor)
+                .thenApplyAsync(response -> {
+                    interceptResponse(response);
+                    return responseDeserializer.deserialize(response);
+                });
     }
 
     public void disconnect() {

src/main/java/com/arangodb/entity/CursorEntity.java

@@ -97,6 +97,7 @@ public Map<String, String> getMeta() {
     public Map<String, String> cleanupMeta(Map<String, String> meta) {
         meta.remove("Content-Length");
         meta.remove("Transfer-Encoding");
+        meta.remove("X-Arango-Queue-Time-Seconds");
         return meta;
     }
 

src/main/java/com/arangodb/internal/ArangoDBImpl.java

@@ -61,12 +61,12 @@ public class ArangoDBImpl extends InternalArangoDB<ArangoExecutorSync> implement
 
     public ArangoDBImpl(final VstCommunicationSync.Builder vstBuilder, final HttpCommunication.Builder httpBuilder,
                         final ArangoSerializationFactory util, final Protocol protocol, final HostResolver hostResolver,
-                        final HostHandler hostHandler, final ArangoContext context) {
+                        final HostHandler hostHandler, final ArangoContext context, int responseQueueTimeSamples, final int timeoutMs) {
 
         super(new ArangoExecutorSync(
                         createProtocol(vstBuilder, httpBuilder, util.get(Serializer.INTERNAL), protocol),
                         util,
-                        new DocumentCache()),
+                        new DocumentCache(), new QueueTimeMetricsImpl(responseQueueTimeSamples), timeoutMs),
                 util,
                 context);
 
@@ -140,6 +140,11 @@ public ArangoDatabase db(final DbName dbName) {
         return new ArangoDatabaseImpl(this, dbName).setCursorInitializer(cursorInitializer);
     }
 
+    @Override
+    public ArangoMetrics metrics() {
+        return new ArangoMetricsImpl(executor.getQueueTimeMetrics());
+    }
+
     @Override
     public Boolean createDatabase(final DbName dbName) throws ArangoDBException {
         return createDatabase(new DBCreateOptions().name(dbName));

src/main/java/com/arangodb/internal/ArangoDefaults.java

@@ -50,5 +50,6 @@ private ArangoDefaults() {
     public static final boolean DEFAULT_ACQUIRE_HOST_LIST = false;
     public static final int DEFAULT_ACQUIRE_HOST_LIST_INTERVAL = 60 * 60 * 1000; // hour
     public static final LoadBalancingStrategy DEFAULT_LOAD_BALANCING_STRATEGY = LoadBalancingStrategy.NONE;
+    public static final int DEFAULT_RESPONSE_QUEUE_TIME_SAMPLES = 10;
 
 }