Graceful reload of native quarkus daemon (i.e. kill SIGHUP)

[col-panic]

Hy there, I created a native quarkus application that runs as daemon in Linux. During startup several information of the system gets detected, that changes every now and then due to configuration changes.

Now I tried to send a signal like kill -SIGHUP $pidofquarkus in the hope, that this will lead to a graceful restart and reload of the quarkus application - but there was no reaction.

I tried some research on the net, but couldn't find this kind of reload information - only the hot reload while being in dev mode.

So - is this a thing? Is quarkus native capable of this? Do I have to activate it?!

[cescoffier]

I need to understand a bit more, you just want to "restart" the native app, is that it?

@zakkak, do you know if native image handles this?

[dmlloyd]

We do not currently support run-time reload without exiting the process AFAIK, at least not outside of dev mode. Normally this isn't too much of an issue since we focus heavily on fast run time startup.

That said, with the incipient service start/stop work, this may become possible in the future.

[col-panic]

@dmlloyd and what about receiving unix signals in general? I found info about sun.misc.Signal to receive and handle unix signals, but doesn't seem to be available?!

I could receive such a signal, and tell my bean to re-initialize itself for example.

[col-panic]

Oh sun.misc.Signal seems available, will have to check if this works out ..

[dmlloyd]

You could possibly use signals yourself in this way. The Signal API is not a supported API in the JDK but in practice it's pretty much universal and it should work if you add a handler like this somewhere:

        Signal.handle(new Signal("HUP"), signal -> reinitializeMyBean());

[dmlloyd]

That said, we might take over this signal at some point in the future, so be aware of that.