[ZEPPELIN-5885] Solve the concurrency clone note

[qinbo12]

What is this PR for?

This pull request migrates solve the concurrency problem caused by multiple concurrent calls to note clone.

What type of PR is it?

[Bug Fix]

What is the Jira issue?

• [ZEPPELIN-5885]

How should this be tested?

• Try to build module zeppelin-zengine by command
  ./mvnw -B -pl 'zeppelin-server,zeppelin-zengine,zeppelin-common,zeppelin-interpreter,zeppelin-jupyter' clean package -
  DskipTests -Pbuild-distr -Pinclude-hadoop -Phadoop3 -Pweb-angular

[Reamer]

Please open a JIRA ticket. A stack trace of the error would be good in the ticket. It would also be good if you use the pull request template.

[qinbo12]

Please open a JIRA ticket. A stack trace of the error would be good in the ticket. It would also be good if you use the pull request template.

Hello, I have JIRA https://issues.apache.org/jira/browse/ZEPPELIN-5885 sheet and provided test case and stack information.

[Reamer]

LGTM

[youshaojun]

hi~, I tried to use the above modifications, but now occasionally throw java.nio.file.NoSuchFileException

Caused by: java.nio.file.NoSuchFileException: /usr/local/zeppelin-0.10.1-bin-all/conf/notebook-authorization.json
	at sun.nio.fs.UnixException.translateToIOException(UnixException.java:86)
	at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
	at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
	at sun.nio.fs.UnixCopyFile.move(UnixCopyFile.java:447)
	at sun.nio.fs.UnixFileSystemProvider.move(UnixFileSystemProvider.java:262)
	at java.nio.file.Files.move(Files.java:1395)
	at org.apache.zeppelin.util.FileUtils.atomicWriteToFile(FileUtils.java:60)
	at org.apache.zeppelin.util.FileUtils.atomicWriteToFile(FileUtils.java:71)
	at org.apache.zeppelin.storage.LocalConfigStorage.save(LocalConfigStorage.java:71)
	at org.apache.zeppelin.notebook.AuthorizationService.saveNoteAuth(AuthorizationService.java:109)
	at org.apache.zeppelin.notebook.Notebook.createNote(Notebook.java:258)
	at org.apache.zeppelin.service.NotebookService.createNote(NotebookService.java:168)

whether this method requires a lock ?

[Reamer]

Are you sure it is because of this change?
I think you have another concurrency problem.

[youshaojun]

Thanks for your reply.
This pull request migrates solve the concurrency problem caused by multiple concurrent calls to org.apache.zeppelin.notebook.AuthorizationService#saveNoteAuth, but this can result in concurrent modifications to notebook authorization.json.

[Reamer]

A synchronized at the saveNoteAuth method should fix the problem. What do you think?

[youshaojun]

Yes, i also think.

[Reamer]

Feel free to prepare a PullRequest with JIRA ticket. Your StackTrace should be included in the JIRA ticket.

[youshaojun]

Mybe a synchronized at the org.apache.zeppelin.util.FileUtils#atomicWriteToFile(java.lang.String, java.io.File, java.util.Set<java.nio.file.attribute.PosixFilePermission>) is a better option.

[Reamer]

I don't think so, because this function is used by all save operations. e.g. when note files are created. These would then block each other.

[youshaojun]

Thanks for your reply. I understand.