Details
Major Description
Running `bin/crawl` for 2 iterations using either the nutch-2.2.1 release or the latest 2.x checkout on a seed file containing for example http://www.mountsinai.on.ca and http://www.dhzb.de (or any other webpage with image files with no obvious file extensions) causes to throw either java.lang.IllegalArgument, IOException and/or OutOfBoundsExceptions in the the readFields function of WebPageWritable:
@Override
public void readFields(DataInput in) throws IOException
@Override
public void write(DataOutput out) throws IOException
2014-02-04 13:50:15,421 INFO util.WebPageWritable - Try reading fields: ...
2014-02-04 13:50:15,423 ERROR util.WebPageWritable - Error - Failed to read fields: http://www.mountsinai.on.ca/carousel/patient-care-banner/image
2014-02-04 13:50:15,423 ERROR util.WebPageWritable - Error - Reading fields of the WebPage class failed - java.lang.IllegalArgumentException
2014-02-04 13:50:15,425 ERROR util.WebPageWritable - Error - Printing stacktrace - java.lang.IllegalArgumentException
Or,
java.lang.IndexOutOfBoundsException
at java.nio.Buffer.checkBounds(Buffer.java:559)
at java.nio.HeapByteBuffer.get(HeapByteBuffer.java:143)
at org.apache.avro.ipc.ByteBufferInputStream.read(ByteBufferInputStream.java:52)
at org.apache.avro.io.DirectBinaryDecoder.doReadBytes(DirectBinaryDecoder.java:183)
at org.apache.avro.io.BinaryDecoder.readString(BinaryDecoder.java:265)
at org.apache.gora.mapreduce.FakeResolvingDecoder.readString(FakeResolvingDecoder.java:131)
at org.apache.avro.generic.GenericDatumReader.readString(GenericDatumReader.java:280)
at org.apache.avro.generic.GenericDatumReader.readMap(GenericDatumReader.java:191)
at org.apache.gora.avro.PersistentDatumReader.readMap(PersistentDatumReader.java:183)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:83)
at org.apache.gora.avro.PersistentDatumReader.readRecord(PersistentDatumReader.java:139)
at org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:80)
at org.apache.gora.avro.PersistentDatumReader.read(PersistentDatumReader.java:103)
at org.apache.gora.avro.PersistentDatumReader.read(PersistentDatumReader.java:98)
at org.apache.gora.mapreduce.PersistentDeserializer.deserialize(PersistentDeserializer.java:73)
at org.apache.gora.mapreduce.PersistentDeserializer.deserialize(PersistentDeserializer.java:36)
at org.apache.gora.util.IOUtils.deserialize(IOUtils.java:205)
at org.apache.nutch.util.WebPageWritable.readFields(WebPageWritable.java:45)
at org.apache.nutch.util.GenericWritableConfigurable.readFields(GenericWritableConfigurable.java:54)
at org.apache.hadoop.io.serializer.WritableSerialization$WritableDeserializer.deserialize(WritableSerialization.java:67)
at org.apache.hadoop.io.serializer.WritableSerialization$WritableDeserializer.deserialize(WritableSerialization.java:40)
at org.apache.hadoop.mapreduce.ReduceContext.nextKeyValue(ReduceContext.java:117)
at org.apache.hadoop.mapreduce.ReduceContext.nextKey(ReduceContext.java:92)
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:176)
at org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:649)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:418)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:398)
The exceptions are caused by image files that sneak through the urlfilter (no extension indicating an image file) and that get (properly?) parsed by tika library.
Note that silently catching the thrown exceptions causes corruption of the Cassandra database, as the deserializer reads over multiple webpage entries in the DataInput. Resulting in a loss of several pages of other host present in the seed file.
Moreover, if one makes sure that the image pages don't end up in the DataInput written by DBUpdateMapper, e.g. by configuring nutch-site.xml to disable the tika parser, the nutch dbupdate finishes properly.
<property>
<name>plugin.excludes</name>
<value>parse-tika</value>
</property>
I highly suspect that the issues are due to gora's dependency on the outdated avro-1.3.3 library.