fix: Removes orphaned topics from transient queries

ksqldb-engine/src/main/java/io/confluent/ksql/engine/KsqlEngine.java

@@ -70,6 +70,7 @@ public class KsqlEngine implements KsqlExecutionContext, Closeable {
   private final String serviceId;
   private final EngineContext primaryContext;
   private final QueryCleanupService cleanupService;
+  private final OrphanedTransientQueryCleaner orphanedTransientQueryCleaner;
 
   public KsqlEngine(
       final ServiceContext serviceContext,
@@ -101,6 +102,7 @@ public KsqlEngine(
       final QueryIdGenerator queryIdGenerator
   ) {
     this.cleanupService = new QueryCleanupService();
+    this.orphanedTransientQueryCleaner = new OrphanedTransientQueryCleaner(this.cleanupService);
     this.primaryContext = EngineContext.create(
         serviceContext,
         processingLogContext,
@@ -312,6 +314,14 @@ public void close() {
     close(false);
   }
 
+  public void cleanupOrphanedInternalTopics(
+      final ServiceContext serviceContext,
+      final Set<String> queryApplicationIds
+  ) {
+    orphanedTransientQueryCleaner
+        .cleanupOrphanedInternalTopics(serviceContext, queryApplicationIds);
+  }
+
   /**
    * Determines if a statement is executable by the engine.
    *

ksqldb-engine/src/main/java/io/confluent/ksql/engine/OrphanedTransientQueryCleaner.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2020 Confluent Inc.
+ *
+ * Licensed under the Confluent Community License (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.confluent.io/confluent-community-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+
+package io.confluent.ksql.engine;
+
+import static java.util.Objects.requireNonNull;
+
+import io.confluent.ksql.exception.KafkaResponseGetFailedException;
+import io.confluent.ksql.services.KafkaTopicClient;
+import io.confluent.ksql.services.ServiceContext;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class OrphanedTransientQueryCleaner {
+
+  private static final Logger LOG = LoggerFactory.getLogger(OrphanedTransientQueryCleaner.class);
+
+  private final QueryCleanupService cleanupService;
+
+  public OrphanedTransientQueryCleaner(final QueryCleanupService cleanupService) {
+    this.cleanupService = requireNonNull(cleanupService);
+  }
+
+  public void cleanupOrphanedInternalTopics(
+      final ServiceContext serviceContext,
+      final Set<String> queryApplicationIds
+  ) {
+    final KafkaTopicClient topicClient = serviceContext.getTopicClient();
+    final Set<String> topicNames;
+    try {
+      topicNames = topicClient.listTopicNames();
+    } catch (KafkaResponseGetFailedException e) {
+      LOG.error("Couldn't fetch topic names", e);
+      return;
+    }
+    // Find any transient query topics
+    final Set<String> orphanedQueryApplicationIds = topicNames.stream()
+        .map(topicName -> queryApplicationIds.stream().filter(topicName::startsWith).findFirst())
+        .filter(Optional::isPresent)
+        .map(Optional::get)
+        .collect(Collectors.toSet());
+    for (final String queryApplicationId : orphanedQueryApplicationIds) {
+      cleanupService.addCleanupTask(
+          new QueryCleanupService.QueryCleanupTask(
+              serviceContext,
+              queryApplicationId,
+              true
+          ));
+    }
+  }
+}

ksqldb-engine/src/main/java/io/confluent/ksql/engine/QueryCleanupService.java

@@ -100,6 +100,10 @@ static class QueryCleanupTask implements Runnable {
       this.isTransient = isTransient;
     }
 
+    public String getAppId() {
+      return appId;
+    }
+
     @Override
     public void run() {
       tryRun(

ksqldb-engine/src/test/java/io/confluent/ksql/engine/OrphanedTransientQueryCleanerTest.java

@@ -0,0 +1,112 @@
+/*
+ * Copyright 2020 Confluent Inc.
+ *
+ * Licensed under the Confluent Community License (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.confluent.io/confluent-community-license
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OF ANY KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+
+package io.confluent.ksql.engine;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.google.common.collect.ImmutableSet;
+import io.confluent.ksql.engine.QueryCleanupService.QueryCleanupTask;
+import io.confluent.ksql.exception.KafkaResponseGetFailedException;
+import io.confluent.ksql.services.KafkaTopicClient;
+import io.confluent.ksql.services.ServiceContext;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Captor;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class OrphanedTransientQueryCleanerTest {
+  private static final String TOPIC1
+      = "_confluent-ksql-default_transient_932097300573686369_1606940079718"
+      + "-Aggregate-GroupBy-repartition";
+  private static final String TOPIC2
+      = "_confluent-ksql-default_transient_932097300573686369_1606940079718"
+      + "-Aggregate-Aggregate-Materialize-changelog";
+  private static final String TOPIC3
+      = "_confluent-ksql-default_transient_123497300573686369_1606940012345"
+      + "-Aggregate-Aggregate-Materialize-changelog";
+
+  private static final String BAD_TOPIC_NAME
+      = "_confluent-ksql-default_node0_transient_bad";
+
+  private static final String APP_ID_1
+      = "_confluent-ksql-default_transient_932097300573686369_1606940079718";
+  private static final String APP_ID_2
+      = "_confluent-ksql-default_transient_123497300573686369_1606940012345";
+
+  @Mock
+  private QueryCleanupService queryCleanupService;
+  @Mock
+  private ServiceContext serviceContext;
+  @Mock
+  private KafkaTopicClient topicClient;
+  @Captor
+  private ArgumentCaptor<QueryCleanupTask> taskCaptor;
+
+  private OrphanedTransientQueryCleaner cleaner;
+
+  @Before
+  public void setUp() {
+    when(serviceContext.getTopicClient()).thenReturn(topicClient);
+    cleaner = new OrphanedTransientQueryCleaner(queryCleanupService);
+  }
+
+  @Test
+  public void shouldCleanup_allApplicationIds() {
+    when(topicClient.listTopicNames()).thenReturn(ImmutableSet.of(TOPIC1, TOPIC2, TOPIC3));
+    cleaner.cleanupOrphanedInternalTopics(serviceContext, ImmutableSet.of(APP_ID_1, APP_ID_2));
+
+    verify(queryCleanupService, times(2)).addCleanupTask(taskCaptor.capture());
+    assertThat(taskCaptor.getAllValues().get(0).getAppId(), is(APP_ID_1));
+    assertThat(taskCaptor.getAllValues().get(1).getAppId(), is(APP_ID_2));
+  }
+
+  @Test
+  public void shouldCleanup_someApplicationIds() {
+    when(topicClient.listTopicNames()).thenReturn(ImmutableSet.of(TOPIC1, TOPIC2));
+    cleaner.cleanupOrphanedInternalTopics(serviceContext, ImmutableSet.of(APP_ID_1, APP_ID_2));
+
+    verify(queryCleanupService, times(1)).addCleanupTask(taskCaptor.capture());
+    assertThat(taskCaptor.getAllValues().get(0).getAppId(), is(APP_ID_1));
+  }
+
+  @Test
+  public void skipNonMatchingTopics() {
+    when(topicClient.listTopicNames()).thenReturn(ImmutableSet.of(TOPIC1, TOPIC2, TOPIC3));
+    cleaner.cleanupOrphanedInternalTopics(serviceContext, ImmutableSet.of(APP_ID_2));
+
+    verify(queryCleanupService, times(1)).addCleanupTask(taskCaptor.capture());
+    assertThat(taskCaptor.getAllValues().get(0).getAppId(), is(APP_ID_2));
+  }
+
+  @Test
+  public void shouldSkip_exception() {
+    when(topicClient.listTopicNames())
+        .thenThrow(new KafkaResponseGetFailedException("error!", new Exception()));
+    cleaner.cleanupOrphanedInternalTopics(serviceContext, ImmutableSet.of());
+
+    verify(queryCleanupService, never()).addCleanupTask(any());
+  }
+}

ksqldb-rest-app/src/main/java/io/confluent/ksql/api/impl/QueryEndpoint.java

@@ -34,6 +34,7 @@
 import io.confluent.ksql.physical.pull.PullQueryResult;
 import io.confluent.ksql.query.BlockingRowQueue;
 import io.confluent.ksql.rest.entity.TableRows;
+import io.confluent.ksql.rest.server.LocalCommands;
 import io.confluent.ksql.rest.server.resources.streaming.PullQueryConfigRoutingOptions;
 import io.confluent.ksql.schema.ksql.Column;
 import io.confluent.ksql.schema.utils.FormatOptions;
@@ -61,21 +62,24 @@ public class QueryEndpoint {
   private final Optional<PullQueryExecutorMetrics> pullQueryMetrics;
   private final RateLimiter rateLimiter;
   private final HARouting routing;
+  private final Optional<LocalCommands> localCommands;
 
   public QueryEndpoint(
       final KsqlEngine ksqlEngine,
       final KsqlConfig ksqlConfig,
       final RoutingFilterFactory routingFilterFactory,
       final Optional<PullQueryExecutorMetrics> pullQueryMetrics,
       final RateLimiter rateLimiter,
-      final HARouting routing
+      final HARouting routing,
+      final Optional<LocalCommands> localCommands
   ) {
     this.ksqlEngine = ksqlEngine;
     this.ksqlConfig = ksqlConfig;
     this.routingFilterFactory = routingFilterFactory;
     this.pullQueryMetrics = pullQueryMetrics;
     this.rateLimiter = rateLimiter;
     this.routing = routing;
+    this.localCommands = localCommands;
   }
 
   public QueryPublisher createQueryPublisher(
@@ -110,6 +114,8 @@ private QueryPublisher createPushQueryPublisher(
     final TransientQueryMetadata queryMetadata = ksqlEngine
         .executeQuery(serviceContext, statement, true);
 
+    localCommands.ifPresent(lc -> lc.write(queryMetadata));
+
     publisher.setQueryHandle(new KsqlQueryHandle(queryMetadata));
 
     return publisher;