[NIFI-8102] TailFile can skip characters if tailing a file on NFS mount

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: Denes Arvay
• Reporter: Denes Arvay
• Created: 18/Dec/20 15:26
• Updated: 18/Dec/20 19:22

Description

As explained in NIFI-7972 on an NFS mount files can have temporary dummy data of NUL bytes. This was addressed at that Jira but the implementation contains a bug that can lead to characters skipped when encountering NUL bytes.

The root cause is that the reader (FileChannel) is not repositioned properly. This wasn't discovered by the newly added unit tests because the second run call (after the simulated NUL byte replacement) was also called with initialize = true parameter, so the respective reader was reinitalized and repositioned. See [1]

[1] https://github.com/apache/nifi/blob/main/nifi-nar-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/java/org/apache/nifi/processors/standard/TestTailFile.java#L198

Issue Links

• links to: GitHub Pull Request #4736