Add little soma workflow example

examples/workflow/client.py

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+from IPython.zmq.parallel.client import Client
+
+client = Client()

examples/workflow/job_wrapper.py

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+#!/usr/bin/env python
+"""Python wrapper around a submitted workflow job.
+
+In reality this would be a more sophisticated script, here we only illustrate
+the basic idea by considering that a submitted 'job' is a Python string to be
+executed.
+"""
+
+import sys
+
+argv = sys.argv
+
+from IPython.zmq.parallel.engine import main
+
+ns = {}
+
+# job
+exec sys.argv[1] in ns
+
+# start engine with job namespace
+main([], user_ns=ns)

examples/workflow/wmanager.py

@@ -0,0 +1,44
+"""Mock workflow manager.
+
+This is a mock work manager whose submitted 'jobs' simply consist of executing
+a python string.  What we want is to see the implementation of the ipython
+controller part.
+"""
+
+from __future__ import print_function
+
+import atexit
+import sys
+
+from subprocess import Popen
+
+def cleanup(controller, engines):
+    """Cleanup routine to shut down all subprocesses we opened."""
+    import signal, time
+    
+    print('Starting cleanup')
+    print('Stopping engines...')
+    for e in engines:
+        e.send_signal(signal.SIGINT)
+    print('Stopping controller...')
+    # so it can shut down its queues
+    controller.send_signal(signal.SIGINT)
+    time.sleep(0.1)
+    print('Killing controller...')
+    controller.kill()
+    print('Cleanup done')
+
+
+if __name__ == '__main__':
+
+    # Start controller in separate process
+    cont = Popen(['python', '-m', 'IPython.zmq.parallel.controller'])
+    print('Started controller')
+
+    # "Submit jobs"
+    eng = []
+    for i in range(4):
+        eng.append(Popen(['python', 'job_wrapper.py','x=%s' % i]))
+
+    # Ensure that all subpro
+    atexit.register(lambda : cleanup(cont, eng))