IOExcpetion while connecting to Twitter Streaming API with Apache Flink

问题

I wrote a small Scala program which uses the Apache Flink Streaming API to read Twitter tweets.

object TwitterWordCount {
  private val properties = "/home/twitter-login.properties"
  def main(args: Array[String]) {
    val env = StreamExecutionEnvironment.getExecutionEnvironment
    val twitterStream = env.addSource(new TwitterSource(properties))
    val tweets = twitterStream
      .flatMap(new JSONParseFlatMap[String, String] {
        override def flatMap(in: String, out: Collector[String]): Unit = {
          if (getString(in, "user.lang") == "en") {
            out.collect(getString(in, "text"))
          }
        }
      })
    tweets.print
    env.execute("tweets")
  }
}

When executing I encounter the following Problem:

14:35:48,353 INFO  com.twitter.hbc.httpclient.ClientBase - twitterSourceClient Establishing a connection
14:35:48,354 DEBUG org.apache.http.impl.conn.PoolingClientConnectionManager - Connection request: [route: {}->http://stream.twitter.com][total kept alive: 0; route allocated: 0 of 2; total allocated: 0 of 20]
14:35:48,354 DEBUG org.apache.http.impl.conn.PoolingClientConnectionManager - Connection leased: [id: 4][route: {}->http://stream.twitter.com][total kept alive: 0; route allocated: 1 of 2; total allocated: 1 of 20]
14:35:48,354 DEBUG org.apache.http.impl.conn.DefaultClientConnectionOperator - Connecting to stream.twitter.com:80
14:35:49,486 DEBUG org.apache.flink.runtime.taskmanager.TaskManager - Received message SendHeartbeat at akka://flink/user/taskmanager_1 from Actor[akka://flink/deadLetters].
14:35:49,486 DEBUG org.apache.flink.runtime.taskmanager.TaskManager - Sending heartbeat to JobManager
14:35:49,487 DEBUG org.apache.flink.runtime.taskmanager.TaskManager - Handled message SendHeartbeat in 1 ms from Actor[akka://flink/deadLetters].
14:35:49,487 DEBUG org.apache.flink.runtime.jobmanager.JobManager - Received message Heartbeat(cb51cdb1bd08879df10bd2198b8e043a,[B@4daaaf5f) at akka://flink/user/jobmanager from Actor[akka://flink/user/taskmanager_1#-64418449].
14:35:49,488 DEBUG org.apache.flink.runtime.jobmanager.JobManager - Received hearbeat message from cb51cdb1bd08879df10bd2198b8e043a.
14:35:49,488 DEBUG org.apache.flink.runtime.instance.InstanceManager - Received heartbeat from TaskManager cb51cdb1bd08879df10bd2198b8e043a @ localhost - 8 slots - URL: akka://flink/user/taskmanager_1
14:35:49,488 DEBUG org.apache.flink.runtime.jobmanager.JobManager - Handled message Heartbeat(cb51cdb1bd08879df10bd2198b8e043a,[B@4daaaf5f) in 0 ms from Actor[akka://flink/user/taskmanager_1#-64418449].
14:35:52,358 DEBUG org.apache.http.impl.conn.DefaultClientConnection - Connection org.apache.http.impl.conn.DefaultClientConnection@64c88f2d closed
14:35:52,358 DEBUG org.apache.http.impl.conn.DefaultClientConnection - Connection org.apache.http.impl.conn.DefaultClientConnection@64c88f2d shut down
14:35:52,358 DEBUG org.apache.http.impl.conn.PoolingClientConnectionManager - Connection [id: 4][route: {}->http://stream.twitter.com] can be kept alive for 9223372036854775807 MILLISECONDS
14:35:52,358 DEBUG org.apache.http.impl.conn.DefaultClientConnection - Connection org.apache.http.impl.conn.DefaultClientConnection@64c88f2d closed
14:35:52,358 DEBUG org.apache.http.impl.conn.PoolingClientConnectionManager - Connection released: [id: 4][route: {}->http://stream.twitter.com][total kept alive: 0; route allocated: 0 of 2; total allocated: 0 of 20]
14:35:52,359 WARN  com.twitter.hbc.httpclient.ClientBase - twitterSourceClient IOException caught when establishing connection to https://stream.twitter.com/1.1/statuses/filter.json?delimited=length
14:35:53,613 WARN  com.twitter.hbc.httpclient.ClientBase - twitterSourceClient failed to establish connection properly
14:35:53,613 INFO  com.twitter.hbc.httpclient.ClientBase - twitterSourceClient Done processing, preparing to close connection
14:35:53,613 DEBUG org.apache.http.impl.conn.PoolingClientConnectionManager - Connection manager is shutting down
14:35:53,613 DEBUG org.apache.http.impl.conn.PoolingClientConnectionManager - Connection manager shut down

The program tries to re-establish the connection. So this 4 lines of log message continue being emitted.

The strange thing about this is, when I run the example provided in the Apache Flink project everything works just fine (I pulled the latest version of master from GitHub). I even use the same properties file. If I copy that example class to my own project the problem state above occurs too.

I used the Flink archetype to create my own project. I tried in version 0.9.1 as well as 0.10-SNAPSHOT. The dependencies flink-scala, flink-streaming-scala, flink-clients and flink-connector-twitter are used in the corresponding version.

Does anyone have experienced a similar issue and can get me on the right track?

回答1:

Debugging the com.twitter.hbc.httpclient.ClientBase brought me to the following Exception: org.apache.http.conn.ConnectTimeoutException: Connect to stream.twitter.com:80 timed out

According to a post on the Twitter Developer forum this happens because of a bug in Apaches HttpClient 4.2. And in fact, resolving the dependency tree on my project shows that the flink-runtime has a dependency on com.amazonaws:aws-java-sdk:1.81 which again has a dependency on org.apache.httpcomponents:httpclient:4.2.

Adding HttpClient 4.2.6 to the dependencies of my project solved the problem temporarily.

回答2:

Thanks @peedeeX21 your solution helped me! Adding explicit dependency to pom.xml will solve problem while running from eclipse, but when one using flink cluster and submits program with flink run - the version packaged withing flink distro still wins.

I've solved it by downloading httpclient-4.2.6.jar jar into flink/lib and renamed it to have "a" (ahttpclient-4.2.6.jar) so it will be added to classpath of flink runtime first(done by bin/config.sh) Hope it will help to someone.

来源：https://stackoverflow.com/questions/32379590/ioexcpetion-while-connecting-to-twitter-streaming-api-with-apache-flink