The file(path) the ApplicationPidListener writes the PID file to should be configurable

[holgerstolzenberg]

It would be great having a configuration property, e.g. spring.application.pid=/var/lock/${appName} which specifies the location the app writes its PID to. Currently this can be passed to ApplicationPidListener via constructor parameter. Problem here is that accessing the Environment may be tricky.

[wilkinsona]

From where would Boot get the value of that property? Neither the Environment nor the ApplicationContext has been created when the ApplicationStartedEvent is fired.

We could, perhaps, provide a system property to set the location, but you can easily do that yourself if you register the listener programatically.

[holgerstolzenberg]

The is the point :-) Wouldn´t it be nice to have the location configured from Environment. Providing a system property is for sure an option, but then you will always have to remember that. Especially when you are using an external config file via SPRING_CONFIG_LOCATION you will have to adapt the shell scripts that launch your production ready app to provide the location of the PID file.

Maybe this is only personal preference here, but I think a central point of configuration is really charming.

Still, I must admit, that I am not sure how to solve it.

Does it make sense to write the PID file only after the application has been fully booted (env created), triggered by a own event.

[philwebb]

I don't think we should change the existing behavior of the ApplicationPidListener but I guess it could listen for the ApplicationEnvironmentPreparedEvent if specifically configured to do so. Perhaps we could offer an alternative constructor that defines which ApplicationEvent triggers the write and also use the Environment if we have it.

new ApplicationPidListener(ApplicationEnvironmentPreparedEvent.class);

[holgerstolzenberg]

That sounds like a reasonable solution!

[holgerstolzenberg]

I have made the needed fixes. The pull request is on the way. I have just signed the CLA.

[holgerstolzenberg]

Currently, the property key for the PID file location is defined via a constant. Maybe this should be changed extending an already present @ConfigurationProperties class?

[wilkinsona]

@dave There's a PR for this issue that allows you to use the Environment (rather than a system property or environment variable): see #1600

[dsyer]

Oops. Idiot didn't read links. But I like my change better. Do we really need to support this changing in application.properties (given that you can compile the default in with the constructor anyway)?

[holgerstolzenberg]

The idea behind the change to application.properties was not to have a second system property to remember which should make productive deployments easier having just a single point of configuration.