NIFI-14156 Improve Bootstrap Process on Windows with Attach API

[exceptionfactory]

Summary

NIFI-14156 Improves the application bootstrap process when running on Microsoft Windows using the Java Attach API to find the application process for status and shutdown. These changes resolve issues with the nifi.cmd stop and nifi.cmd status commands not working.

The restructured bootstrap process for NiFi 2 uses the ProcessHandle interface added in Java 9. The OpenJDK implementation for Linux and macOS provides command arguments for the associated process, but the implementation in Windows does not provide command arguments as of Java 21. JDK-8176725 describes the lack of support on Windows.

To maintain the stateless behavior of the application bootstrap process on Windows, changes in this pull request introduce new process handle discovery classes based on the Attach API and the VirtualMachine class. The VirtualMachine.getSystemProperties() method returns the system properties containing the information required to identify the bootstrap and application processes. This approach is implemented using feature detection when ProcessHandle.Info.arguments() is empty, preserving existing behavior on Linux and macOS.

Additional changes include correcting the nifi.cmd to avoid passing the application properties argument to the bootstrap process, and adjusting the start command behavior to launch the application in a new minimized window. The adjusted start behavior then returns to the command prompt, enabling subsequent commands such as status or stop as needed.

Tracking

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Issue Tracking

• Apache NiFi Jira issue created

Pull Request Tracking

• Pull Request title starts with Apache NiFi Jira issue number, such as NIFI-00000
• Pull Request commit message starts with Apache NiFi Jira issue number, as such NIFI-00000

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Build

• Build completed using mvn clean install -P contrib-check
  • JDK 21

Licensing

• New dependencies are compatible with the Apache License 2.0 according to the License Policy
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Documentation

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[balazsgerner]

Thank you for the fix, I reviewed the changes and tested the start-stop and status functionality on Windows and MacOS as well, everything is working as expected.
One thing to note is that when I start nifi on Windows, a minified windows appears on the taskbar. Is this wanted/exptected behaviour? See attached image.

[exceptionfactory]

Thank you for the fix, I reviewed the changes and tested the start-stop and status functionality on Windows and MacOS as well, everything is working as expected. One thing to note is that when I start nifi on Windows, a minified windows appears on the taskbar. Is this wanted/exptected behaviour?

Thanks for the testing and feedback @balazsgerner!

Yes, the minimized background window is expected when running nifi.cmd start. The updates to nifi.cmd start include this change so that the NiFi process starts in the background and the command returns to the prompt. The previous behavior left the command running in the same prompt window, blocking further use of that prompt window. The behavior adjustment aligns more closely to nifi.sh start on Linux and macOS, starting NiFi in the background and returning to the command prompt.

[mark-bathori]

Thanks @exceptionfactory for fixing this issue and thanks @balazsgerner for testing.
The changes looks good to me +1
Merging.