[FLUME-2066] Spool directory source can get stuck in a "Serializer has been closed" loop when retireCurrentFile throws an exception

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.4.0, 1.3.1
• Component/s: Sinks+Sources
• Assignee: Phil Scala
• Reporter: Phil Scala
• Created: 03/Jun/13 16:37
• Updated: 18/Sep/14 20:47

Description

The following 2 java files have similar code and are affected by this issue...

1.31. SpoolingfileLineReader.java
1.4 ReliableSpoolingFileEventReader.java

retireCurrentFile is called by 1 caller (readLines in 1.3.1 and readEvents in 1.4)

 
retireCurrentFile(); 
      currentFile = getNextFile(); 
      if (!currentFile.isPresent()) { 
        return Collections.emptyList(); 
      } 

if retireCurrentFile throws an exception after closing the reader (there are a few causes for an exception tobe raised which are described below) the the currentFile still points to the attempted to be retired file. This causes subsequent calls to readLines/readEvents to raise a "Serializer has been closed" exception. At this point the application needs to be shutdown in order to rectify the problem. If Flume is left running for a while, the logs are littered with the error, so you have to go to the initial error logged to understand what happened.

Exceptions raised in "retireCurrentFile()"
IlligalStateException when the file modified date changes
IlligalStateException when the size changes
IllegalStateException when renaming the current file and the target file already exists (with different sizes)
IllegalStateException when renaming the current file and the target file already exists [non windows]
FlumeException when renameTo does not return true.

The documentation does say:
*Warning This channel expects that only immutable, uniquely named files are dropped in the spooling directory. If duplicate names are used, or files are modified while being read, the source will fail with an error message *

I am not sure however if the intention was to get caught into the "Serializer has been closed" loop. 3 possible solutions:

1. Re-spool the retired file, this will cause duplicates and could get caught in a loop of constantly spooling this file.
2. Log an error and continue spooling the next files.
3. Shutdown

I like option..2

Issue Links

• contains: FLUME-2119 duplicate files cause flume to enter irrecoverable state