Replace EventHandler with StreamEventPublisher Currently both EventHandler and StreamEventPublisher provide the same functionality. Remove EventHandler and switch EventTopic.STREAM_EVENT_TOPIC key to `gerritEvents` and default value to `gerrit`. Bug: Issue 14907 Change-Id: Ia47de40fabc571de271bf61a79f4d1892991391a

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutor.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutor.java
deleted file mode 100644
index 07bbbf7..0000000
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutor.java
+++ /dev/null

@@ -1,24 +0,0 @@
-// Copyright (C) 2015 The Android Open Source Project
-//
-// 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.
-
-package com.googlesource.gerrit.plugins.multisite.event;
-
-import static java.lang.annotation.RetentionPolicy.RUNTIME;
-
-import com.google.inject.BindingAnnotation;
-import java.lang.annotation.Retention;
-
-@Retention(RUNTIME)
-@BindingAnnotation
-@interface EventExecutor {}

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutorProvider.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutorProvider.java
deleted file mode 100644
index e4979f9..0000000
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutorProvider.java
+++ /dev/null

@@ -1,29 +0,0 @@
-// Copyright (C) 2015 The Android Open Source Project
-//
-// 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.
-
-package com.googlesource.gerrit.plugins.multisite.event;
-
-import com.google.gerrit.server.git.WorkQueue;
-import com.google.inject.Inject;
-import com.google.inject.Singleton;
-import com.googlesource.gerrit.plugins.multisite.ExecutorProvider;
-
-@Singleton
-class EventExecutorProvider extends ExecutorProvider {
-
-  @Inject
-  EventExecutorProvider(WorkQueue workQueue) {
-    super(workQueue, 1, "Forward-Stream-Event");
-  }
-}

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventHandler.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventHandler.java
deleted file mode 100644
index e001e15..0000000
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventHandler.java
+++ /dev/null

@@ -1,66 +0,0 @@
-// Copyright (C) 2015 The Android Open Source Project
-//
-// 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.
-
-package com.googlesource.gerrit.plugins.multisite.event;
-
-import com.google.gerrit.extensions.registration.DynamicSet;
-import com.google.gerrit.server.config.GerritInstanceId;
-import com.google.gerrit.server.events.Event;
-import com.google.gerrit.server.events.EventListener;
-import com.google.gerrit.server.events.ProjectEvent;
-import com.google.inject.Inject;
-import com.googlesource.gerrit.plugins.multisite.forwarder.StreamEventForwarder;
-import java.util.concurrent.Executor;
-
-class EventHandler implements EventListener {
-  private final Executor executor;
-  private final DynamicSet<StreamEventForwarder> forwarders;
-  private final String nodeInstanceId;
-
-  @Inject
-  EventHandler(
-      DynamicSet<StreamEventForwarder> forwarders,
-      @EventExecutor Executor executor,
-      @GerritInstanceId String nodeInstanceId) {
-    this.forwarders = forwarders;
-    this.executor = executor;
-    this.nodeInstanceId = nodeInstanceId;
-  }
-
-  @Override
-  public void onEvent(Event event) {
-
-    if (nodeInstanceId.equals(event.instanceId) && event instanceof ProjectEvent) {
-      executor.execute(new EventTask(event));
-    }
-  }
-
-  class EventTask implements Runnable {
-    private final Event event;
-
-    EventTask(Event event) {
-      this.event = event;
-    }
-
-    @Override
-    public void run() {
-      forwarders.forEach(f -> f.send(event));
-    }
-
-    @Override
-    public String toString() {
-      return String.format("Send event '%s' to target instance", event.type);
-    }
-  }
-}

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventModule.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventModule.java
index 663d8e5..94d7867 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventModule.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/event/EventModule.java

@@ -24,7 +24,6 @@
 import com.googlesource.gerrit.plugins.multisite.Configuration;
 import com.googlesource.gerrit.plugins.multisite.forwarder.events.EventTopic;
 import com.googlesource.gerrit.plugins.multisite.validation.ProjectVersionRefUpdate;
-import java.util.concurrent.Executor;
 
 public class EventModule extends LifecycleModule {
   private final Configuration configuration;
@@ -36,13 +35,10 @@
 
   @Override
   protected void configure() {
-    bind(Executor.class).annotatedWith(EventExecutor.class).toProvider(EventExecutorProvider.class);
-    listener().to(EventExecutorProvider.class);
-    DynamicSet.bind(binder(), EventListener.class).to(EventHandler.class);
     DynamicSet.bind(binder(), EventListener.class).to(ProjectVersionRefUpdate.class);
     bind(new TypeLiteral<String>() {})
         .annotatedWith(Names.named(StreamEventPublisher.STREAM_EVENTS_TOPIC))
-        .toInstance(EventTopic.GERRIT_TOPIC.topic(configuration));
+        .toInstance(EventTopic.STREAM_EVENT_TOPIC.topic(configuration));
 
     DynamicSet.bind(binder(), EventListener.class).to(StreamEventPublisher.class);
   }

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/ForwarderModule.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/ForwarderModule.java
index ca17004..1d36e23 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/ForwarderModule.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/ForwarderModule.java

@@ -24,6 +24,5 @@
     DynamicSet.setOf(binder(), CacheEvictionForwarder.class);
     DynamicSet.setOf(binder(), IndexEventForwarder.class);
     DynamicSet.setOf(binder(), ProjectListUpdateForwarder.class);
-    DynamicSet.setOf(binder(), StreamEventForwarder.class);
   }
 }

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/StreamEventForwarder.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/StreamEventForwarder.java
deleted file mode 100644
index 79a9af2..0000000
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/StreamEventForwarder.java
+++ /dev/null

@@ -1,27 +0,0 @@
-// Copyright (C) 2019 The Android Open Source Project
-//
-// 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.
-
-package com.googlesource.gerrit.plugins.multisite.forwarder;
-
-import com.google.gerrit.server.events.Event;
-
-public interface StreamEventForwarder {
-  /**
-   * Forward a stream event to the other master.
-   *
-   * @param event the event to forward.
-   * @return true if successful, otherwise false.
-   */
-  boolean send(Event event);
-}

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/broker/BrokerForwarderModule.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/broker/BrokerForwarderModule.java
index 6bd6437..d6c5658 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/broker/BrokerForwarderModule.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/broker/BrokerForwarderModule.java

@@ -19,7 +19,6 @@
 import com.googlesource.gerrit.plugins.multisite.forwarder.CacheEvictionForwarder;
 import com.googlesource.gerrit.plugins.multisite.forwarder.IndexEventForwarder;
 import com.googlesource.gerrit.plugins.multisite.forwarder.ProjectListUpdateForwarder;
-import com.googlesource.gerrit.plugins.multisite.forwarder.StreamEventForwarder;
 
 public class BrokerForwarderModule extends LifecycleModule {
   @Override
@@ -28,6 +27,5 @@
     DynamicSet.bind(binder(), CacheEvictionForwarder.class).to(BrokerCacheEvictionForwarder.class);
     DynamicSet.bind(binder(), ProjectListUpdateForwarder.class)
         .to(BrokerProjectListUpdateForwarder.class);
-    DynamicSet.bind(binder(), StreamEventForwarder.class).to(BrokerStreamEventForwarder.class);
   }
 }

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/broker/BrokerStreamEventForwarder.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/broker/BrokerStreamEventForwarder.java
deleted file mode 100644
index 8a020fc..0000000
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/broker/BrokerStreamEventForwarder.java
+++ /dev/null

@@ -1,40 +0,0 @@
-// Copyright (C) 2019 The Android Open Source Project
-//
-// 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.
-
-package com.googlesource.gerrit.plugins.multisite.forwarder.broker;
-
-import com.google.gerrit.server.events.Event;
-import com.google.inject.Inject;
-import com.google.inject.Singleton;
-import com.googlesource.gerrit.plugins.multisite.Configuration;
-import com.googlesource.gerrit.plugins.multisite.broker.BrokerApiWrapper;
-import com.googlesource.gerrit.plugins.multisite.forwarder.StreamEventForwarder;
-import com.googlesource.gerrit.plugins.multisite.forwarder.events.EventTopic;
-
-@Singleton
-public class BrokerStreamEventForwarder implements StreamEventForwarder {
-  private final BrokerApiWrapper broker;
-  private final Configuration cfg;
-
-  @Inject
-  BrokerStreamEventForwarder(BrokerApiWrapper broker, Configuration cfg) {
-    this.broker = broker;
-    this.cfg = cfg;
-  }
-
-  @Override
-  public boolean send(Event event) {
-    return broker.sendSync(EventTopic.STREAM_EVENT_TOPIC.topic(cfg), event);
-  }
-}

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/events/EventTopic.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/events/EventTopic.java
index d8e7607..3255bcf 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/events/EventTopic.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/forwarder/events/EventTopic.java

@@ -21,39 +21,7 @@
   BATCH_INDEX_TOPIC("GERRIT.EVENT.BATCH.INDEX", "batchIndexEvent"),
   CACHE_TOPIC("GERRIT.EVENT.CACHE", "cacheEvent"),
   PROJECT_LIST_TOPIC("GERRIT.EVENT.PROJECT.LIST", "projectListEvent"),
-  /**
-   * the STREAM_EVENT_TOPICS and the GERRIT_TOPIC are both used to publish stream events. It might
-   * not be immediately intuitive why there are _two_ streams for this, rather than one. These are
-   * some gotchas regarding this:
-   *
-   * <ul>
-   *   <li>A subset of stream events is published to the STREAM_EVENT_TOPIC (i.e. only global
-   *       project events). This is done by the EventHandler.
-   *   <li>All, unfiltered gerrit events are published to a topic called `gerrit` (the
-   *       GERRIT_TOPIC). This is done by the StreamEventPublisher provided by the events-broker
-   *       library.
-   * </ul>
-   *
-   * Historically, the GERRIT_TOPIC existed to allow the streaming of all stream events. With the
-   * introduction of multi-site however, events had to be wrapped into EventMessage and streamed
-   * separately, in order to provide a header containing the instance-id that produced that message.
-   * For this purpose a *new* STREAM_EVENT_TOPIC topic was introduced.
-   *
-   * <p><a href="https://bugs.chromium.org/p/gerrit/issues/detail?id=14823">Issue 14823</a> now
-   * removed the need of EventMessage altogether,so that the `STREAM_EVENT_TOPIC` stream,
-   * conceptually would not be needed anymore.
-   *
-   * <p>However, before the `STREAM_EVENT_TOPIC` stream can be effectively removed, the filtering of
-   * the events needs to happen on the receiving side, as explained in <a
-   * href="https://bugs.chromium.org/p/gerrit/issues/detail?id=14835">Issue 14835</a>.
-   *
-   * <p>This would allow to *all* events to be streamed to the STREAM_EVENT_TOPICS.
-   *
-   * @deprecated Use {@link #GERRIT_TOPIC} instead.
-   */
-  @Deprecated
-  STREAM_EVENT_TOPIC("GERRIT.EVENT.STREAM", "streamEvent"),
-  GERRIT_TOPIC("gerrit", "gerritEvents");
+  STREAM_EVENT_TOPIC("gerrit", "streamEvent");
 
   private final String topic;
   private final String aliasKey;

diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index d7d2239..7eedc6a 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md

@@ -58,13 +58,7 @@
 :   Name of the topic to use for publishing indexing events
     Defaults to GERRIT.EVENT.INDEX
 
-```broker.streamEventTopic```
-:   Name of the topic to use for publishing stream events. Note that only
-    project events are streamed and only for global projects (see
-    `projects.pattern`).
-    Defaults to GERRIT.EVENT.STREAM
-
-`broker.gerritEventsTopic`
+`broker.streamEventTopic`
 :   Name of the topic to use for publishing all stream events.
     Default: gerrit
 

diff --git a/src/test/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutorProviderTest.java b/src/test/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutorProviderTest.java
deleted file mode 100644
index a025dd0..0000000
--- a/src/test/java/com/googlesource/gerrit/plugins/multisite/event/EventExecutorProviderTest.java
+++ /dev/null

@@ -1,55 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// 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.
-
-package com.googlesource.gerrit.plugins.multisite.event;
-
-import static com.google.common.truth.Truth.assertThat;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
-
-import com.google.gerrit.server.git.WorkQueue;
-import java.util.concurrent.ScheduledThreadPoolExecutor;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.mockito.Mock;
-import org.mockito.junit.MockitoJUnitRunner;
-
-@RunWith(MockitoJUnitRunner.class)
-public class EventExecutorProviderTest {
-  @Mock private ScheduledThreadPoolExecutor executorMock;
-  private EventExecutorProvider eventsExecutorProvider;
-
-  @Before
-  public void setUp() throws Exception {
-    WorkQueue workQueueMock = mock(WorkQueue.class);
-    when(workQueueMock.createQueue(1, "Forward-Stream-Event")).thenReturn(executorMock);
-    eventsExecutorProvider = new EventExecutorProvider(workQueueMock);
-  }
-
-  @Test
-  public void shouldReturnExecutor() throws Exception {
-    assertThat(eventsExecutorProvider.get()).isEqualTo(executorMock);
-  }
-
-  @Test
-  public void testStop() throws Exception {
-    eventsExecutorProvider.start();
-    assertThat(eventsExecutorProvider.get()).isEqualTo(executorMock);
-    eventsExecutorProvider.stop();
-    verify(executorMock).shutdown();
-    assertThat(eventsExecutorProvider.get()).isNull();
-  }
-}

diff --git a/src/test/java/com/googlesource/gerrit/plugins/multisite/event/EventHandlerTest.java b/src/test/java/com/googlesource/gerrit/plugins/multisite/event/EventHandlerTest.java
deleted file mode 100644
index 1d75f9d..0000000
--- a/src/test/java/com/googlesource/gerrit/plugins/multisite/event/EventHandlerTest.java
+++ /dev/null

@@ -1,85 +0,0 @@
-// Copyright (C) 2015 The Android Open Source Project
-//
-// 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.
-
-package com.googlesource.gerrit.plugins.multisite.event;
-
-import static com.google.common.truth.Truth.assertThat;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.verifyZeroInteractions;
-
-import com.google.common.util.concurrent.MoreExecutors;
-import com.google.gerrit.extensions.registration.DynamicSet;
-import com.google.gerrit.server.events.Event;
-import com.google.gerrit.server.events.ProjectEvent;
-import com.google.gerrit.server.events.RefUpdatedEvent;
-import com.googlesource.gerrit.plugins.multisite.event.EventHandler.EventTask;
-import com.googlesource.gerrit.plugins.multisite.forwarder.StreamEventForwarder;
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.mockito.Mock;
-import org.mockito.junit.MockitoJUnitRunner;
-
-@RunWith(MockitoJUnitRunner.class)
-public class EventHandlerTest {
-  private static final String DEFAULT_INSTANCE_ID = "instance-id";
-
-  private EventHandler eventHandler;
-
-  @Mock private StreamEventForwarder forwarder;
-
-  @Before
-  public void setUp() {
-    eventHandler =
-        new EventHandler(
-            asDynamicSet(forwarder), MoreExecutors.directExecutor(), DEFAULT_INSTANCE_ID);
-  }
-
-  private DynamicSet<StreamEventForwarder> asDynamicSet(StreamEventForwarder forwarder) {
-    DynamicSet<StreamEventForwarder> result = new DynamicSet<>();
-    result.add("multi-site", forwarder);
-    return result;
-  }
-
-  @Test
-  public void shouldForwardAnyProjectEvent() throws Exception {
-    ProjectEvent event = mock(ProjectEvent.class);
-    event.instanceId = DEFAULT_INSTANCE_ID;
-    eventHandler.onEvent(event);
-    verify(forwarder).send(event);
-  }
-
-  @Test
-  public void shouldNotForwardNonProjectEvent() throws Exception {
-    eventHandler.onEvent(mock(Event.class));
-    verifyZeroInteractions(forwarder);
-  }
-
-  @Test
-  public void shouldNotForwardIfAlreadyForwardedEvent() throws Exception {
-    Event event = mock(ProjectEvent.class);
-    event.instanceId = "instance-id-2";
-    eventHandler.onEvent(event);
-    verifyZeroInteractions(forwarder);
-  }
-
-  @Test
-  public void tesEventTaskToString() throws Exception {
-    Event event = new RefUpdatedEvent();
-    EventTask task = eventHandler.new EventTask(event);
-    assertThat(task.toString())
-        .isEqualTo(String.format("Send event '%s' to target instance", event.type));
-  }
-}