PortInUseFailureAnalyzer should attempt to detect the bounding PID in case of a port conflict

[yonatang]

Description

Right now, if the port that Spring attempts to bind if already in use, Spring Boot will provide you a general notification saying the port is bound, without any other details:

Description:

Web server failed to start. Port 8080 was already in use.

Action:

Identify and stop the process that's listening on port 8080 or configure this application to listen on another port.

It could be very convenient if the analyzer will make a best-effort attempt to detect the bounding PID and provide it as part of the failure details. Something like this:

Description:

Web server failed to start. Port 8080 was already in use by java (PID: 76781).

Action:

Stop the process java (PID: 76781) that's listening on port 8080 or configure this application to listen on another port.

That would be particularly useful when dealing with development environment with multiple services running at the same time, or a headless process that is still running after an IDE crash.

Implementation details

Java has no way to directly access the details of other processes, but since this is a best-effort attempt, we can try to invoke an OS-specific command to fetch the information. If the attempt to get it failed or timed out, we can fall back to the old generic message; either way to app failed to start, so no harm done.

Assistance required

I don't have a windows environment, I would need help to check it works well in that OS. Running the PortInUseFailureAnalyzerTests unit test on a Windows machine should be suffice, it will invoke the necessary OS specific command.

[philwebb]

Thanks for the PR, but I personally think the complexity to benefit ratio is little high for this one. Flagging to see what the rest of the team think.

[yonatang]

@philwebb fair enough, I admit I’m a bit spoiled and tend to lean toward the more comfortable side of things 😅

Notice that some frameworks, such as the react-dev-utils, will let you know that piece of information:

[wilkinsona]

I'm not sure that it's worth investing much more in this failure analysis while it only works in an English locale.

[philwebb]

Thanks @wilkinsona, given that additional problem I'm pretty convinced that this isn't something we should add. Thanks anyway for the PR @yonatang!