Once you install dm Server, you may want to run it as a service or daemon. In this post, I will give you an excerpt from Chapter 2 of dm Server 2.0 in Action.
Running dm Server as daemon
On UNIX platforms, you can use nohup $SERVER_HOME/bin/startup.sh& to allow the dm Server’s shell process tree to become child of the init (or launchd) process and thus survive SIGHUP signal.
Configuring dm Server as Windows service
On Windows platforms, you can use Project Kenai’s winsw to run the dm Server as Windows service. The service wrapper can execute arbitrary executable file and pass it different command line arguments on service startup and shutdown.
To get started, download winsw from its homepage at http://projectkenai.com/projects/winsw/pages/Home. Once you have downloaded the winsw.exe, rename it to, for example, dmss.exe and copy it to %SERVER_HOME%\bin. The listing of %SERVER_HOME%\bin should now show files in Listing 1.
Listing 1. Files in %SERVER_HOME%\bin
C:\>dir %SERVER_HOME%\bin
Volume in drive C has no label.
Volume Serial Number is 7408-8BB9
Directory of C:\opt\springsource-dm-server-2\bin
24/07/2009 14:49 <dir> .
24/07/2009 14:49 </dir><dir > ..
24/07/2009 14:21 31,744 dmss.exe
14/07/2009 16:42 953 jconsole.bat
14/07/2009 16:42 1,071 jconsole.sh
14/07/2009 16:42 2,468 jmxPermissions.vbs
14/07/2009 16:42 291 setupClasspath.bat
14/07/2009 16:42 658 setupClasspath.sh
14/07/2009 16:42 1,017 shutdown.bat
14/07/2009 16:42 1,243 shutdown.sh
14/07/2009 16:42 3,561 startup.bat
14/07/2009 16:42 3,459 startup.sh
15 File(s) 50,298 bytes
2 Dir(s) 1,316,659,200 bytes free
Because the service wrapper (now renamed to dmss.exe) executes the same executable to start or stop the service, we must create an executable that can decide whether to start or stop the dm Server based on command line argument. Let’s call this executable dmscontrol.bat; if we pass the run command line argument, we want it to call the startup.bat. Similarly, if we pass the stop command line argument, we want it to call the shutdown.bat. We show the entire source code of dmscontrol.bat below:
@ECHO OFF IF "%~1"=="run" CALL %SERVER_HOME%\bin\startup.bat IF "%~1"=="stop" CALL %SERVER_HOME%\bin\shutdown.bat
The final piece of the puzzle is the service configuration file. The service wrapper will look for a configuration file whose file name matches the executable of the service wrapper, but with xml extension. In our case, dmss.exe will look for dmss.xml. Take a look at Listing 2, which shows the dmss.xml service configuration file.
Listing 2. The service wrapper configuration file
01 <service> 02 <id>dmserver2</id> 03 <name>dm Server 2.0</name> 04 <description> 05 Controls the SpringSource dm Server 2.0 06 </description> 07 <env name="JAVA_HOME" 08 value="c:\Program Files\Java\jdk1.6.0_14" /> 09 <executable>%SERVER_HOME%\bin\dmscontrol.bat</executable> 10 <startargument>run</startargument> 11 <stopargument>stop</stopargument> 12 </service> 02 The service identifier, it must start with a letter and must not contain spaces 03 The service name, this is the name that the Services listing will show 05 The description of the service that the Services listing will show 08 We need to set the JAVA_HOME environment variable for the service 09 The path to the service executable 10 The command line argument that the service wrapper will pass to the service executable to start the service 11 The command line argument that the service wrapper will pass to the service executable to stop the service
Before we can install the service, we must check that the permissions on the dm Server’s directory allow access from the service’s account. By default, the service will run under the SYSTEM account, therefore, we must give the SYSTEM account full control of the %SERVER_HOME% directory. Once this is done, we must execute the following commands:
cd %SYSTEM_HOME%\bin dmss install
This will install the dm Server service, the proof is in the pudding – the Services listing in Figure 1.
Figure 1. The dm Server service appearing in the Services listing
Notice in the Services listing that the name matches the contents of the <name> element in the dmss.xml file and description matches the contents of the <description> element in the configuration file. We can now start the service; when the service starts, its shell process will become child of the services.exe process (see Figure 2).
Figure 2. Process tree showing the dm Server’s dmss.exe wrapper
You can verify that the service starts dm Server successfully by going to http://localhost:8080, you should see the splash screen you saw when you started the dm Server by running %SERVER_HOME%\bin\startup.bat.
Note on security
Regardless of whether you are running dm Server on UNIX or Windows, you should create a separate user account to run it. Having a separate account to run the dm Server will help limit the damage a potential successful attacker may cause.
Now that we have explored the different ways to start and run dm Server, let’s find out how we can control it once it’s running. We will begin by looking at the simple web administrative console, followed by the more complex OSGi console.
And there you have it!
Whether you’re running UNIX or Windows, you can now configure dm Server to survive a logoff!