Run ServiceStack as a daemon on Linux

When your web application is predominantly javascript with a REST service at the back-end there are many reasons why you might want to simply serve the static content through apache (or alternative) and run the service as a ...well... service. Some examples are:

• Faster start-up times
• Avoiding lengthy XML configuration files
• Problems with mono ASP.NET memory leaks and random exceptions.

Fortunately this is quite simple.

Service example

The earlier example of self hosting provides a good starting point, but needs to be modified slightly if running as a daemon.

using System;
using System.Reflection;
using Mono.Unix;
using Mono.Unix.Native;

using Funq;
using ServiceStack.ServiceHost;
using ServiceStack.WebHost.Endpoints;


namespace ServiceStackExample
{
	public class AppHost : AppHostHttpListenerBase
	{
		public AppHost() : base("Example", Assembly.GetExecutingAssembly())
		{
		}
		
		public override void Configure(Container container)
		{
		}
	}
	
	class Program
	{
		static void Main(string[] args)
		{
			//Initialize app host
			var appHost = new AppHost();
			appHost.Init();
			appHost.Start("http://127.0.0.1:8080/");
	
			UnixSignal [] signals = new UnixSignal[] { 
				new UnixSignal(Signum.SIGINT), 
				new UnixSignal(Signum.SIGTERM), 
			};
	
			// Wait for a unix signal
			for (bool exit = false; !exit; )
			{
				int id = UnixSignal.WaitAny(signals);
				
				if (id >= 0 && id < signals.Length)
				{
					if (signals[id].IsSet) exit = true;
				}
			}
		}
	}
}

Be aware that this makes use of posix functionality and will therefore not work under Windows. You will need to add the Mono.Posix library to your project references.

Daemonising the application

As it stands the project produces a console application that responds to unix signals (press ctrl-c to exit if you are running it from a terminal). If your target platform is Ubuntu then the simplest way to automatically run your application as a daemon is to use an upstart script.

Create the following at /etc/init/example.conf

# ServiceStack Example Application

description "ServiceStack Example"
author      "ServiceStack"

start on started rc
stop on stopping rc

respawn

exec start-stop-daemon --start -c username --exec mono /path/to/application.exe

Ideally we would start the service when apache is ready but apache does not yet emit upstart events. Additional conditions could include a database dependency if required, for example "start on started mysql". Replace "username" with that of an unprivileged user on the system; this avoids the dangers of running the application as root.

You should now be able to start your application with

$ sudo start example

and access the default service information by visiting http://127.0.0.1:8080 in your browser of choice.

Configuring apache

The following example configuration uses proxying to expose the REST service through apache, so you must ensure that mod_proxy has been enabled first:

$ sudo a2enmod proxy

Next create a file at /etc/apache2/sites-available/example

ProxyPass /api http://127.0.0.1:8080/ retry=0 max=50
ProxyPassReverse /api http://127.0.0.1:8080/

<VirtualHost *:80>
	DocumentRoot /path/to/static/content/

	<Directory />
	</Directory>

	<Directory /path/to/static/content/>
		Options Indexes MultiViews
		AllowOverride None
		Order allow,deny
		allow from all
	</Directory>
</VirtualHost>

Your site can then be enabled with

$ sudo a2ensite example

although you will need to disable the default sites if they are enabled. After restarting/reloading apache you should find your static content at http://127.0.0.1 and the REST service at http://127.0.0.1/api.

Alternative nginx configuration

Create a file at /etc/nginx/sites-available/example

server {
	listen 80;
	root /path/to/static/content;
	index index.html;

	location /api/ {
		proxy_pass http://127.0.0.1:8080/;
	}
}

To enable the site simply symlink from sites-available to sites-enabled (nginx does not have an equivalent a2ensite tool) and then restart/reload nginx. (N.B. The trailing forward slash on the proxy pass URL is important).

Other hosting options on Linux / Mono

This StackOverflow answer lists the different options for hosting ServiceStack on Linux with Mono.