Add a property for configuring additional livereload paths

[itsAkshayDubey]

This PR enhances the functionality related to issue #40342 by introducing configurable additional paths for live reload. This feature mirrors the existing capability for configuring additional paths for application restart.

[mhalbritter]

Hey, thanks for the PR. I've looked at the changes and have some feedback:

You're creating a new FileSystemWatcher bean to watch for live reload changes. However, the restart functionality already has a FileSystemWatcher to watch for changes. It would be good to reuse that FileSystemWatcher so that it can trigger a restart (if restart paths change) or trigger a live reload (if reload paths change).

That would mean that pollInterval and quietPeriod can't be configured separately, but I don't think this is a big deal.

Do you have the time to implement this idea?

[itsAkshayDubey]

Hi @mhalbritter , sure I'll submit my PR super soon.

[philwebb]

Hi @itsAkshayDubey, any luck implementing the requested changes?

[itsAkshayDubey]

On it, will submit my PR in next 2 days.

[itsAkshayDubey]

Hi @mhalbritter @philwebb , kindly have a look.

[mhalbritter]

Hello @itsAkshayDubey. Thanks for taking another go at it, but unfortunately, the changes aren't what we are looking for. Now we have two new FileSystemWatcher. In that comment above I suggested that we instead use the already existing FileSystemWatcher bean which is already there to watch for restart changes and use it to also watch for livereload changes. That way we would only have one FileSystemWatcher.

Do you want to give it another go or should we abort here?

[itsAkshayDubey]

Hi @mhalbritter,
Thank you for your input. I'll definitely address this. However, I would appreciate a bit of clarification to proceed effectively.
As I understand it, RestartConfiguration is a conditional bean based on the spring.devtools.restart.enabled property. To access the FileSystemWatcher from RestartConfiguration, we would need the bean to be available. In the current implementation, I am utilising FileSystemWatcher when the RestartConfiguration bean is present, or otherwise, creating a new instance.
Could you kindly advise on the best approach to consistently use the same FileSystemWatcher from the RestartConfiguration bean, regardless of its conditional nature?

[mhalbritter]

The FileSystemWatcher is created in org.springframework.boot.devtools.autoconfigure.LocalDevToolsAutoConfiguration.RestartConfiguration#newFileSystemWatcher. Right now, it uses org.springframework.boot.devtools.autoconfigure.DevToolsProperties.Restart#additionalPaths to configure additional paths.

My idea was that we add the org.springframework.boot.devtools.autoconfigure.DevToolsProperties.Livereload#additionalPaths to the same FileSystemWatcher, and then check in in the listeners if the change should lead to a restart or a livereload. Then we only need one FileSystemWatcher.

I haven't looked into detail how we need to move the auto-configuration classes and conditions around, but I guess at least for the FileSystemWatcher we need a condition which is true if either spring.devtools.restart.enabled=true OR spring.devtools.livereload.enabled=true. This can be done with a org.springframework.boot.autoconfigure.condition.AnyNestedCondition.

I'm not 100% sure that this will work, because there's a lot going on in the restart functionality.