CXF does not remove temporary files and kept file handlers open

Environment

• Red Hat Enterprise Application Platform (EAP) 7.2
  • CXF 3.2.5.redhat-00001
    • LoggingInInterceptor is enabled
    • message attachments size exceeds the org.apache.cxf.io.CachedWriter.Threshold (64kb by default)

Issue

• When the message attachment exceeds 64kb, CXF writes it as a temporary file but never deletes it.
• When the is system running on Windows, temporary files are locked and cannot be deleted.
• When LoggingInInterceptor is enabled and CXF receive a message with an attachment greater than 64k a file handlers leak takes place.

Resolution

Note: The following workaround is risky because it can easily lead to an OOM.

The workaround is to increase the size of the threshold that drives the write on the disk of the message attachment with a value greater than any expected attachment size, using the system property org.apache.cxf.io.CachedWriter.Threshold (byte expressed with an integer, default 65536).

The fix has been scheduled for EAP 7.3.3.GA.

Root Cause

The component LoggingInInterceptor uses a CacheWriter to cache message attachment greater than the threshold (64k by default) on disk, but it does not close it and keeps file handler open indefinitely.

Diagnostic Steps

• Check the CXF temporary file folder (org.apache.cxf.io.CachedOutputStream.OutputDirectory, the Java temp dir by default) for at least one file with the prefix cos and suffix tmp.
• A check with the command lsof <cos tmp file> will prove that its file handler is held by the EAP process.

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