How to stop an OSGI Application from command line

Question

I do have a running osgi (equinox container) application. It will been started via a bash script. See felix gogo shell

java -jar ... _osgi.jar -console 1234 &

This all works pretty well and I also can stop it via

telnet localhost 1234
<osgi>stop 0

But what I am looking for is how can I embed this into a bash script to stop the osgi application.

I already tried this

echo stop 0 | telnet localhost 1234

but this doesn't work. So if someone has idea how to put this in a bash script, please let me know.

Answer 1

Telneting into the Gogo shell seems like an awfully fragile solution. Why not write your application to support standard POSIX signal handling? Then you could simply kill it with kill -s TERM <pid>.

For example the following bundle activator installs a shutdown hook that cleanly shuts down the framework, equivalently to stop 0:

import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.launch.Framework;

public class ShutdownHookActivator implements BundleActivator {

    @Override
    public void start(final BundleContext context) {
        Thread hook = new Thread() {
            @Override
            public void run() {
                System.out.println("Shutdown hook invoked, stopping OSGi Framework.");
                try {
                    Framework systemBundle = context.getBundle(0).adapt(Framework.class);
                    systemBundle.stop();
                    System.out.println("Waiting up to 2s for OSGi shutdown to complete...");
                    systemBundle.waitForStop(2000);
                } catch (Exception e) {
                    System.err.println("Failed to cleanly shutdown OSGi Framework: " + e.getMessage());
                    e.printStackTrace();
                }
            }
        };
        System.out.println("Installing shutdown hook.");
        Runtime.getRuntime().addShutdownHook(hook);
    }

    @Override
    public void stop(BundleContext context) throws Exception {
    }

}

NB: if you are in control of the launcher code that starts the OSGi Framework, you should probably install the shutdown hook there rather from a separate bundle.

Update

In bash, the $! variable evaluates to the PID of the last executed background command. You can save this into your own variable for later reference, e.g.:

# Launch app:
java -jar ... &
MY_PID=$!

# Later when you want to stop your app:
kill $MY_PID