[BEAM-3649] HadoopSeekableByteChannel breaks when backing InputStream doesn't supporte ByteBuffers

• Type: Bug
• Status: Resolved
• Priority: P3
• Resolution: Duplicate
• Affects Version/s: 2.0.0, 2.1.0, 2.2.0
• Fix Version/s: Not applicable
• Component/s: io-java-hadoop-file-system
• Assignee: Unassigned
• Reporter: Guillaume Balaine
• Created: 08/Feb/18 15:25
• Updated: 24/Jul/20 20:18
• Resolved: 26/Feb/18 16:36

Description

This happened last summer, when I wanted to use S3A as the backing HDFS access implementation. 

This is because while this method is called : https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSDataInputStream.java#L145

This class does not implement ByteBuffer readable https://github.com/apache/hadoop/blob/trunk/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java

I fixed it by manually incrementing the read position and copying the backing array instead of buffering.

https://github.com/Igosuki/beam/commit/3838f0db43b6422833a045d1f097f6d7643219f1

I know the s3 direct implementation is the preferred path, but this is possible, and likely happens to a lot of developers.