Running PHP as a Service on Win32

[Update: I wrote some docs for the php manual]

So, you've written some kind of super-duper daemon process in PHP, perhaps using the event extension and stream_socket_server(). On Unix, it's quite a simple matter to have it run from init (or maybe inetd) when your machine starts... but doing the same on windows isn't possible without some hacks. Until now.

Last night I put together 2 new extensions for windows; the first of these is called win32service and it allows you run your PHP scripts from the "Service Control Manager" (SCM). The SCM is roughly analagous to the init process on unix, in that it runs tasks on startup and monitors their status, optionally restarting them if something goes awry.

I've included a sample service script that demonstrates minimal usage. Before you can run a script as a service, you need to register it with the SCM; in the sample, you do this by running it with the "install" argument on the command line. Once installed, you can use either the services MMC snap-in (run services.msc, or look for it under "Administrative Tools") or the good old fashined "net" command to launch or stop the service. I prefer the latter: 

   net start dummyphp

The output from the command should indicate the service started correctly; use the task manager to verify this--you should see a php.exe process running as SYSTEM. This dummy service does nothing much; just sleeps and waits for the SCM to tell it to stop; lets do that now: 

   net stop dummyphp

Again, the output from that command should indicate that the service stopped, and your task manager should no longer show php.exe running as SYSTEM. Now that we've proved that it works, we should remove the same from the SCM; running the script with the "uninstall" argument will do this.

It's all pretty straight-forward; the most complicated part is the win32_create_service() function; the first argument is an array that describes the service; the following keys are supported:

  • service - the short name of the service. You can't have two services with the same name.
  • display - the display name of the service.
  • user - the account name under which to run the service. If omitted, runs as the local system account
  • password - the password to match the "user" setting.
  • path - full path to the binary to run. If omitted, the full path to the currently running process will be used (typically php.exe)
  • params - command line parameters to pass to the binary. You'll probably want to specify the full path to a PHP script, plus some parameter to indicate that the script should run as a service.

(there are some more keys but they're not fully supported yet)

When it comes to actually running your service, you should call win32_start_service_ctrl_dispatcher() and pass in the name of the service. This function checks-in with the SCM; it is especially important that you do this as soon as possible in your script, as the SCM blocks while it waits for you to check-in--you can cause system-wide issues if you take too long.

While your service is running, you should periodically check to see if the SCM has requested that you stop. One way to do this is to wrap the main body of your service code in a while loop like this: 

<?php
   while (WIN32_SERVICE_CONTROL_STOP != win32_get_last_control_message()) {
      // do stuff here, but try not to take more than a few seconds
   }
?>

If you already have an event loop, you can fold the above into your application. If you're using the event extension, you can schedule a recurrent timed event to check for the stop condition.

And that's pretty much all there is to say for now. I strongly recommend that you look through the MSDN documentation on services; it's very valuable background information.

The binaries for PHP 5 should show up under http://snaps.php.net/win32/PECL_5_0/ in the next couple of hours.

Enjoy :)