[BEAM-53] Java-only pub/sub source and sink (streaming only)

pom.xml

@@ -103,6 +103,7 @@
     <avro.version>1.7.7</avro.version>
     <bigquery.version>v2-rev248-1.21.0</bigquery.version>
     <bigtable.version>0.2.3</bigtable.version>
+    <pubsubgrpc.version>0.0.2</pubsubgrpc.version>
     <clouddebugger.version>v2-rev6-1.21.0</clouddebugger.version>
     <dataflow.version>v1b3-rev22-1.21.0</dataflow.version>
     <dataflow.proto.version>0.5.160222</dataflow.proto.version>

sdks/java/core/pom.xml

@@ -389,6 +389,40 @@
       <version>0.12.0</version>
     </dependency>
 
+    <dependency>
+      <groupId>com.google.auth</groupId>
+      <artifactId>google-auth-library-oauth2-http</artifactId>
+      <version>0.3.1</version>
+      <exclusions>
+        <!-- Exclude an old version of guava that is being pulled
+             in by a transitive dependency of google-api-client -->
+        <exclusion>
+          <groupId>com.google.guava</groupId>
+          <artifactId>guava-jdk5</artifactId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+
+    <dependency>
+      <groupId>io.netty</groupId>
+      <artifactId>netty-handler</artifactId>
+      <version>4.1.0.Beta8</version>
+    </dependency>
+
+    <dependency>
+      <groupId>com.google.api.grpc</groupId>
+      <artifactId>grpc-pubsub-v1</artifactId>
+      <version>${pubsubgrpc.version}</version>
+      <exclusions>
+        <!-- Exclude an old version of guava that is being pulled
+             in by a transitive dependency of google-api-client -->
+        <exclusion>
+          <groupId>com.google.guava</groupId>
+          <artifactId>guava-jdk5</artifactId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+
     <dependency>
       <groupId>com.google.cloud.bigtable</groupId>
       <artifactId>bigtable-protos</artifactId>

sdks/java/core/src/main/java/com/google/cloud/dataflow/sdk/io/PubsubClient.java

@@ -0,0 +1,176 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.google.cloud.dataflow.sdk.io;
+
+import java.io.IOException;
+import java.util.Collection;
+
+/**
+ * A helper interface for talking to pub/sub via an underlying transport.
+ */
+public interface PubsubClient extends AutoCloseable {
+  /**
+   * Gracefully close the underlying transport.
+   */
+  @Override
+  void close();
+
+  /**
+   * A message to be sent to pub/sub.
+   */
+  class OutgoingMessage {
+    /**
+     * Underlying (encoded) element.
+     */
+    public final byte[] elementBytes;
+
+    /**
+     * Timestamp for element (ms since epoch).
+     */
+    public final long timestampMsSinceEpoch;
+
+    public OutgoingMessage(byte[] elementBytes, long timestampMsSinceEpoch) {
+      this.elementBytes = elementBytes;
+      this.timestampMsSinceEpoch = timestampMsSinceEpoch;
+    }
+  }
+
+  /**
+   * A message received from pub/sub.
+   */
+  class IncomingMessage {
+    /**
+     * Underlying (encoded) element.
+     */
+    public final byte[] elementBytes;
+
+    /**
+     * Timestamp for element (ms since epoch). Either pub/sub's processing time,
+     * or the custom timestamp associated with the message.
+     */
+    public final long timestampMsSinceEpoch;
+
+    /**
+     * Timestamp (in system time) at which we requested the message (ms since epoch).
+     */
+    public final long requestTimeMsSinceEpoch;
+
+    /**
+     * Id to pass back to pub/sub to acknowledge receipt of this message.
+     */
+    public final String ackId;
+
+    /**
+     * Id to pass to the runner to distinguish this message from all others.
+     */
+    public final byte[] recordId;
+
+    public IncomingMessage(
+        byte[] elementBytes,
+        long timestampMsSinceEpoch,
+        long requestTimeMsSinceEpoch,
+        String ackId,
+        byte[] recordId) {
+      this.elementBytes = elementBytes;
+      this.timestampMsSinceEpoch = timestampMsSinceEpoch;
+      this.requestTimeMsSinceEpoch = requestTimeMsSinceEpoch;
+      this.ackId = ackId;
+      this.recordId = recordId;
+    }
+  }
+
+  /**
+   * Publish {@code outgoingMessages} to pub/sub {@code topic}. Return number of messages
+   * published.
+   *
+   * @throws IOException
+   */
+  int publish(String topic, Iterable<OutgoingMessage> outgoingMessages) throws IOException;
+
+  /**
+   * Request the next batch of up to {@code batchSize} messages from {@code subscription}.
+   * Return the received messages, or empty collection if none were available. Does not
+   * wait for messages to arrive. Returned messages will record heir request time
+   * as {@code requestTimeMsSinceEpoch}.
+   *
+   * @throws IOException
+   */
+  Collection<IncomingMessage> pull(
+      long requestTimeMsSinceEpoch, String subscription, int
+      batchSize) throws IOException;
+
+  /**
+   * Acknowldege messages from {@code subscription} with {@code ackIds}.
+   *
+   * @throws IOException
+   */
+  void acknowledge(String subscription, Iterable<String> ackIds) throws IOException;
+
+  /**
+   * Modify the ack deadline for messages from {@code subscription} with {@code ackIds} to
+   * be {@code deadlineSeconds} from now.
+   *
+   * @throws IOException
+   */
+  void modifyAckDeadline(String subscription, Iterable<String> ackIds, int deadlineSeconds)
+      throws IOException;
+
+  /**
+   * Create {@code topic}.
+   *
+   * @throws IOException
+   */
+  void createTopic(String topic) throws IOException;
+
+  /*
+   * Delete {@code topic}.
+   *
+   * @throws IOException
+   */
+  void deleteTopic(String topic) throws IOException;
+
+  /**
+   * Return a list of topics for {@code project}.
+   *
+   * @throws IOException
+   */
+  Collection<String> listTopics(String project) throws IOException;
+
+  /**
+   * Create {@code subscription} to {@code topic}.
+   *
+   * @throws IOException
+   */
+  void createSubscription(String topic, String subscription, int ackDeadlineSeconds) throws
+      IOException;
+
+  /**
+   * Delete {@code subscription}.
+   *
+   * @throws IOException
+   */
+  void deleteSubscription(String subscription) throws IOException;
+
+  /**
+   * Return a list of subscriptions for {@code topic} in {@code project}.
+   *
+   * @throws IOException
+   */
+  Collection<String> listSubscriptions(String project, String topic) throws IOException;
+}