在我的Storm集群中读取AWS SQS队列时,导致这些ParseError异常的原因是什么

Question

我正在使用Storm 0.8.1从Amazon SQS队列中读取传入消息,并在执行此操作时获得一致的异常:

2013-12-02 02:21:38 executor [ERROR] 
java.lang.RuntimeException: com.amazonaws.AmazonClientException: Unable to unmarshall response (ParseError at [row,col]:[1,1]
Message: JAXP00010001: The parser has encountered more than "64000" entity expansions in this document; this is the limit imposed by the JDK.)
        at REDACTED.spouts.SqsQueueSpout.handleNextTuple(SqsQueueSpout.java:219)
        at REDACTED.spouts.SqsQueueSpout.nextTuple(SqsQueueSpout.java:88)
        at backtype.storm.daemon.executor$fn__3976$fn__4017$fn__4018.invoke(executor.clj:447)
        at backtype.storm.util$async_loop$fn__465.invoke(util.clj:377)
        at clojure.lang.AFn.run(AFn.java:24)
        at java.lang.Thread.run(Thread.java:701)
Caused by: com.amazonaws.AmazonClientException: Unable to unmarshall response (ParseError at [row,col]:[1,1]
Message: JAXP00010001: The parser has encountered more than "64000" entity expansions in this document; this is the limit imposed by the JDK.)
        at com.amazonaws.http.AmazonHttpClient.handleResponse(AmazonHttpClient.java:524)
        at com.amazonaws.http.AmazonHttpClient.executeHelper(AmazonHttpClient.java:298)
        at com.amazonaws.http.AmazonHttpClient.execute(AmazonHttpClient.java:167)
        at com.amazonaws.services.sqs.AmazonSQSClient.invoke(AmazonSQSClient.java:812)
        at com.amazonaws.services.sqs.AmazonSQSClient.receiveMessage(AmazonSQSClient.java:575)
        at REDACTED.spouts.SqsQueueSpout.handleNextTuple(SqsQueueSpout.java:191)
        ... 5 more
Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1]
Message: JAXP00010001: The parser has encountered more than "64000" entity expansions in this document; this is the limit imposed by the JDK.
        at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.setInputSource(XMLStreamReaderImpl.java:219)
        at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.<init>(XMLStreamReaderImpl.java:189)
        at com.sun.xml.internal.stream.XMLInputFactoryImpl.getXMLStreamReaderImpl(XMLInputFactoryImpl.java:277)
        at com.sun.xml.internal.stream.XMLInputFactoryImpl.createXMLStreamReader(XMLInputFactoryImpl.java:129)
        at com.sun.xml.internal.stream.XMLInputFactoryImpl.createXMLEventReader(XMLInputFactoryImpl.java:78)
        at com.amazonaws.http.StaxResponseHandler.handle(StaxResponseHandler.java:85)
        at com.amazonaws.http.StaxResponseHandler.handle(StaxResponseHandler.java:41)
        at com.amazonaws.http.AmazonHttpClient.handleResponse(AmazonHttpClient.java:503)
        ... 10 more

我调试了队列中的数据,一切看起来都不错.我无法弄清楚为什么API的XML响应会导致这些问题.有任何想法吗？

Answer 1

多年来在这里回答我自己的问题.

目前,Oracle和OpenJDK的Java中存在XML扩展限制处理错误,导致共享计数器在解析多个XML文档时达到默认上限.

1. https://blogs.oracle.com/joew/entry/jdk_7u45_aws_issue_123
2. https://bugs.openjdk.java.net/browse/JDK-8028111
3. https://github.com/aws/aws-sdk-java/issues/123

虽然我认为我们的版本(6b27-1.12.6-1ubuntu0.12.04.4)没有受到影响,但运行OpenJDK错误报告中给出的示例代码确实证实我们容易受到该错误的影响.

为了解决这个问题,我需要传递jdk.xml.entityExpansionLimit=0给风暴工作者.通过storm.yaml在我的群集中添加以下内容,我能够缓解此问题.

supervisor.childopts: "-Djdk.xml.entityExpansionLimit=0"
worker.childopts: "-Djdk.xml.entityExpansionLimit=0"

我应该注意到,从技术上讲,这会让你受到拒绝服务攻击,但由于我们的XML文档只来自SQS,我并不担心有人伪造恶意XML来杀死我们的工作者.