new_contents: """
  This is an example topology for the distributed cloud emulator (dcemulator).
  (c) 2015 by Manuel Peuster <manuel.peuster@upb.de>
  
  
  This is an example that shows how a user of the emulation tool can
  define network topologies with multiple emulated cloud data centers.
  
  The definition is done with a Python API which looks very similar to the
  Mininet API (in fact it is a wrapper for it).
  
  We only specify the topology *between* data centers not within a single
  data center (data center internal setups or placements are not of interest,
  we want to experiment with VNF chains deployed across multiple PoPs).
  
  The original Mininet API has to be completely hidden and not be used by this
  script.
  """
  import logging
  from mininet.log import setLogLevel
  from emuvim.dcemulator.net import DCNetwork
  from emuvim.api.rest.compute import RestApiEndpoint
  #from emuvim.api.zerorpc.compute import ZeroRpcApiEndpoint
  from emuvim.api.zerorpc.network import ZeroRpcApiEndpointDCNetwork
  
  logging.basicConfig(level=logging.INFO)
  
  
  def create_topology1():
      """
      1. Create a data center network object (DCNetwork)
      """
      net = DCNetwork()
  
      """
      1b. add a monitoring agent to the DCNetwork
      """
      mon_api = ZeroRpcApiEndpointDCNetwork("0.0.0.0", 5151)
      mon_api.connectDCNetwork(net)
      mon_api.start()
      """
      2. Add (logical) data centers to the topology
         (each data center is one "bigswitch" in our simplified
          first prototype)
      """
      dc1 = net.addDatacenter("datacenter1")
      dc2 = net.addDatacenter("datacenter2")
      dc3 = net.addDatacenter("long_data_center_name3")
      dc4 = net.addDatacenter(
          "datacenter4",
          metadata={"mydata": "we can also add arbitrary metadata to each DC"})
  
      """
      3. You can add additional SDN switches for data center
         interconnections to the network.
      """
      s1 = net.addSwitch("s1")
  
      """
      4. Add links between your data centers and additional switches
         to define you topology.
         These links can use Mininet's features to limit bw, add delay or jitter.
      """
      net.addLink(dc1, dc2)
      net.addLink("datacenter1", s1)
      net.addLink(s1, dc3)
      net.addLink(s1, "datacenter4")
  
      """
      5. We want to access and control our data centers from the outside,
         e.g., we want to connect an orchestrator to start/stop compute
         resources aka. VNFs (represented by Docker containers in the emulated)
  
         So we need to instantiate API endpoints (e.g. a zerorpc or REST
         interface). Depending on the endpoint implementations, we can connect
         one or more data centers to it, which can then be controlled through
         this API, e.g., start/stop/list compute instances.
      """
      # create a new instance of a endpoint implementation
      api1 = RestApiEndpoint("127.0.0.1", 5000)
      # connect data centers to this endpoint
      api1.connectDatacenter(dc1)
      api1.connectDatacenter(dc2)
      api1.connectDatacenter(dc3)
      api1.connectDatacenter(dc4)
      # run API endpoint server (in another thread, don't block)
      api1.start()
  
      """
      6. Finally we are done and can start our network (the emulator).
         We can also enter the Mininet CLI to interactively interact
         with our compute resources (just like in default Mininet).
         But we can also implement fully automated experiments that
         can be executed again and again.
      """
      net.start()
      net.CLI()
      # when the user types exit in the CLI, we stop the emulator
      net.stop()
  
  
  def main():
      setLogLevel('info')  # set Mininet loglevel
      create_topology1()
  
  
  if __name__ == '__main__':
      main()
  
subject: add rest api