Killing gracefully a .NET Core daemon running on Linux

Question

I created a .NET Core console application running as a daemon on a Ubuntu 14.04 machine.

I want to stop the service without forcing it, being able to handle a kill event.

How can I achieve this?

Answer 1

.NET Core has considerably evolved since @Stefano's answer a year ago. In .NET Core 2.0, you can now use the well-known AppDomain.CurrentDomain.ProcessExit event instead of AssemblyLoadContext.Default.Unloading. It works fine for console applications on Linux, also in Docker.

Answer 2

You want to be able to send a SIGTERM to the running process:

kill <PID> 

And the process should handle it to shutdown correctly.

Unfortunately .NET Core is not well documented, but it is capable of handling Unix signals (in a different fashion from Mono). GitHub issue

If you use Ubuntu with Upstart, what you need is to have an init script that sends the the kill signal on a stop request: Example init script

Add a dependency to your project.json:

"System.Runtime.Loader": "4.0.0" 

This will give you the AssemblyLoadContext.

Then you can handle the SIGTERM event:

AssemblyLoadContext.Default.Unloading += MethodInvokedOnSigTerm; 

Note:

Using Mono, the correct way of handling it would be through the UnixSignal: Mono.Unix.Native.Signum.SIGTERM

EDIT:

As @Marc pointed out in his recent answer, this is not anymore the best way to achieve this. From .NET Core 2.0 AppDomain.CurrentDomain.ProcessExit is the supported event.