jlleitschuh / jenkinsci__overthere-remoting

Jenkins remoting + XebiaLabs overthere

Jenkins Remoting + Overthere

Jenkins remoting is a library that Jenkins uses to communicate between a master and slaves. It provides a mechanism to remotely execute code between two JVMs while transparently sending necessary Java class files.

Overthere is a virtual file system library by XebiaLabs that allows a JVM to remotely access a file system and run processes.

This small library brings them together, such that the Jenkins remoting mechanism can be used as a remoting mechanism behind Overthere. Furthermore, this is done as a filter of OverthereConnection, thereby making an OverthereConnection on one JVM transparently available on another JVM.

resides in JVM 1                    resides in JVM 2

+--------------+                    +--------------+                 +---------------+
| Overthere    |  Jenkins remoting  | Overthere    |  SSH/CIFS etc.  | actual        |
|   Connection |------------------->|   Connection |---------------->|   file system |
+--------------+                    +--------------+                 +---------------+

Usage

First, you create Overthere connection like you normally do:

OverthereConnection oc = ...;

To make it portable across the remoting layer, wrap this in RemotableOverthereConnection:

oc = new RemotableOverthereConnection(oc);

This object can be now safely passed between two channels:

Channel ch = ...;

ch.call(new Callable<Void, IOException>() {
    public Void call() throws IOException {
        // this code executes on the other side of the channel

        for (OverthereFile f : oc.getFile("/").listFiles()) {
            System.out.println(f.getPath());
        }

        OverthereProcess p = oc.startProcess(CmdLine.build("ls", "-la"));
        p.getStdin().close();
        IOUtils.copy(p.getStdout(), System.out);
        System.out.println("exit code=" + p.waitFor());

        return null;
    }
});

... or it can be used as a return value from Callable.

See the Demo class in src/test/java for a complete example.