[SPARK-13843][STREAMING] Remove streaming-flume, streaming-mqtt, streaming-zeromq, streaming-akka, streaming-twitter to Spark packages

## What changes were proposed in this pull request?

Currently there are a few sub-projects, each for integrating with different external sources for Streaming.  Now that we have better ability to include external libraries (spark packages) and with Spark 2.0 coming up, we can move the following projects out of Spark to https://github.com/spark-packages

- streaming-flume
- streaming-akka
- streaming-mqtt
- streaming-zeromq
- streaming-twitter

They are just some ancillary packages and considering the overhead of maintenance, running tests and PR failures, it's better to maintain them out of Spark. In addition, these projects can have their different release cycles and we can release them faster.

I have already copied these projects to https://github.com/spark-packages

## How was this patch tested?

Jenkins tests

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #11672 from zsxwing/remove-external-pkg.

5 files changed, 0 insertions, 299 deletions

diff --git a/external/mqtt/src/test/java/org/apache/spark/streaming/LocalJavaStreamingContext.java b/external/mqtt/src/test/java/org/apache/spark/streaming/LocalJavaStreamingContext.java
deleted file mode 100644
index cfedb5a042..0000000000
--- a/external/mqtt/src/test/java/org/apache/spark/streaming/LocalJavaStreamingContext.java
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- * 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 org.apache.spark.streaming;
-
-import org.apache.spark.SparkConf;
-import org.apache.spark.streaming.api.java.JavaStreamingContext;
-import org.junit.After;
-import org.junit.Before;
-
-public abstract class LocalJavaStreamingContext {
-
-    protected transient JavaStreamingContext ssc;
-
-    @Before
-    public void setUp() {
-        SparkConf conf = new SparkConf()
-            .setMaster("local[2]")
-            .setAppName("test")
-            .set("spark.streaming.clock", "org.apache.spark.util.ManualClock");
-        ssc = new JavaStreamingContext(conf, new Duration(1000));
-        ssc.checkpoint("checkpoint");
-    }
-
-    @After
-    public void tearDown() {
-        ssc.stop();
-        ssc = null;
-    }
-}
diff --git a/external/mqtt/src/test/java/org/apache/spark/streaming/mqtt/JavaMQTTStreamSuite.java b/external/mqtt/src/test/java/org/apache/spark/streaming/mqtt/JavaMQTTStreamSuite.java
deleted file mode 100644
index ce5aa1e0cd..0000000000
--- a/external/mqtt/src/test/java/org/apache/spark/streaming/mqtt/JavaMQTTStreamSuite.java
+++ /dev/null
@@ -1,37 +0,0 @@
-/*
- * 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 org.apache.spark.streaming.mqtt;
-
-import org.apache.spark.storage.StorageLevel;
-import org.apache.spark.streaming.api.java.JavaReceiverInputDStream;
-import org.junit.Test;
-
-import org.apache.spark.streaming.LocalJavaStreamingContext;
-
-public class JavaMQTTStreamSuite extends LocalJavaStreamingContext {
-  @Test
-  public void testMQTTStream() {
-    String brokerUrl = "abc";
-    String topic = "def";
-
-    // tests the API, does not actually test data receiving
-    JavaReceiverInputDStream<String> test1 = MQTTUtils.createStream(ssc, brokerUrl, topic);
-    JavaReceiverInputDStream<String> test2 = MQTTUtils.createStream(ssc, brokerUrl, topic,
-      StorageLevel.MEMORY_AND_DISK_SER_2());
-  }
-}
diff --git a/external/mqtt/src/test/resources/log4j.properties b/external/mqtt/src/test/resources/log4j.properties
deleted file mode 100644
index 75e3b53a09..0000000000
--- a/external/mqtt/src/test/resources/log4j.properties
+++ /dev/null
@@ -1,28 +0,0 @@
-#
-# 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.
-#
-
-# Set everything to be logged to the file target/unit-tests.log
-log4j.rootCategory=INFO, file
-log4j.appender.file=org.apache.log4j.FileAppender
-log4j.appender.file.append=true
-log4j.appender.file.file=target/unit-tests.log
-log4j.appender.file.layout=org.apache.log4j.PatternLayout
-log4j.appender.file.layout.ConversionPattern=%d{yy/MM/dd HH:mm:ss.SSS} %t %p %c{1}: %m%n
-
-# Ignore messages below warning level from Jetty, because it's a bit verbose
-log4j.logger.org.spark-project.jetty=WARN
-
diff --git a/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala b/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala
deleted file mode 100644
index fdcd18c6fb..0000000000
--- a/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * 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 org.apache.spark.streaming.mqtt
-
-import scala.concurrent.duration._
-import scala.language.postfixOps
-
-import org.scalatest.BeforeAndAfter
-import org.scalatest.concurrent.Eventually
-
-import org.apache.spark.SparkFunSuite
-import org.apache.spark.storage.StorageLevel
-import org.apache.spark.streaming.{Milliseconds, StreamingContext}
-
-class MQTTStreamSuite extends SparkFunSuite with Eventually with BeforeAndAfter {
-
-  private val batchDuration = Milliseconds(500)
-  private val master = "local[2]"
-  private val framework = this.getClass.getSimpleName
-  private val topic = "def"
-
-  private var ssc: StreamingContext = _
-  private var mqttTestUtils: MQTTTestUtils = _
-
-  before {
-    ssc = new StreamingContext(master, framework, batchDuration)
-    mqttTestUtils = new MQTTTestUtils
-    mqttTestUtils.setup()
-  }
-
-  after {
-    if (ssc != null) {
-      ssc.stop()
-      ssc = null
-    }
-    if (mqttTestUtils != null) {
-      mqttTestUtils.teardown()
-      mqttTestUtils = null
-    }
-  }
-
-  test("mqtt input stream") {
-    val sendMessage = "MQTT demo for spark streaming"
-    val receiveStream = MQTTUtils.createStream(ssc, "tcp://" + mqttTestUtils.brokerUri, topic,
-      StorageLevel.MEMORY_ONLY)
-
-    @volatile var receiveMessage: List[String] = List()
-    receiveStream.foreachRDD { rdd =>
-      if (rdd.collect.length > 0) {
-        receiveMessage = receiveMessage ::: List(rdd.first)
-        receiveMessage
-      }
-    }
-
-    ssc.start()
-
-    // Retry it because we don't know when the receiver will start.
-    eventually(timeout(10000 milliseconds), interval(100 milliseconds)) {
-      mqttTestUtils.publishData(topic, sendMessage)
-      assert(sendMessage.equals(receiveMessage(0)))
-    }
-    ssc.stop()
-  }
-}
diff --git a/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTTestUtils.scala b/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTTestUtils.scala
deleted file mode 100644
index 3680c13605..0000000000
--- a/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTTestUtils.scala
+++ /dev/null
@@ -1,111 +0,0 @@
-/*
- * 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 org.apache.spark.streaming.mqtt
-
-import java.net.{ServerSocket, URI}
-import java.nio.charset.StandardCharsets
-
-import scala.language.postfixOps
-
-import org.apache.activemq.broker.{BrokerService, TransportConnector}
-import org.apache.commons.lang3.RandomUtils
-import org.eclipse.paho.client.mqttv3._
-import org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence
-
-import org.apache.spark.{Logging, SparkConf}
-import org.apache.spark.util.Utils
-
-/**
- * Share codes for Scala and Python unit tests
- */
-private[mqtt] class MQTTTestUtils extends Logging {
-
-  private val persistenceDir = Utils.createTempDir()
-  private val brokerHost = "localhost"
-  private val brokerPort = findFreePort()
-
-  private var broker: BrokerService = _
-  private var connector: TransportConnector = _
-
-  def brokerUri: String = {
-    s"$brokerHost:$brokerPort"
-  }
-
-  def setup(): Unit = {
-    broker = new BrokerService()
-    broker.setDataDirectoryFile(Utils.createTempDir())
-    connector = new TransportConnector()
-    connector.setName("mqtt")
-    connector.setUri(new URI("mqtt://" + brokerUri))
-    broker.addConnector(connector)
-    broker.start()
-  }
-
-  def teardown(): Unit = {
-    if (broker != null) {
-      broker.stop()
-      broker = null
-    }
-    if (connector != null) {
-      connector.stop()
-      connector = null
-    }
-    Utils.deleteRecursively(persistenceDir)
-  }
-
-  private def findFreePort(): Int = {
-    val candidatePort = RandomUtils.nextInt(1024, 65536)
-    Utils.startServiceOnPort(candidatePort, (trialPort: Int) => {
-      val socket = new ServerSocket(trialPort)
-      socket.close()
-      (null, trialPort)
-    }, new SparkConf())._2
-  }
-
-  def publishData(topic: String, data: String): Unit = {
-    var client: MqttClient = null
-    try {
-      val persistence = new MqttDefaultFilePersistence(persistenceDir.getAbsolutePath)
-      client = new MqttClient("tcp://" + brokerUri, MqttClient.generateClientId(), persistence)
-      client.connect()
-      if (client.isConnected) {
-        val msgTopic = client.getTopic(topic)
-        val message = new MqttMessage(data.getBytes(StandardCharsets.UTF_8))
-        message.setQos(1)
-        message.setRetained(true)
-
-        for (i <- 0 to 10) {
-          try {
-            msgTopic.publish(message)
-          } catch {
-            case e: MqttException if e.getReasonCode == MqttException.REASON_CODE_MAX_INFLIGHT =>
-              // wait for Spark streaming to consume something from the message queue
-              Thread.sleep(50)
-          }
-        }
-      }
-    } finally {
-      if (client != null) {
-        client.disconnect()
-        client.close()
-        client = null
-      }
-    }
-  }
-
-}