Real-Time Event Service


File: DevGuideExamples/EventServices/RTEC_MCast_Federated/README


This directory contains an example that shows how to create and
federate real-time event channels using the classes in EC_Gateway_UDP.h.
Depending on the options, it will use either UDP or multicast to link
the event channels.

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Note: To run this example, you must first run the Naming Service, e.g.:

  $TAO_ROOT/orbsvcs/Naming_Service/Naming_Service -o ns.ior&

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To start the supplier/EC processes on a single host and federate them
using UDP, do the following (after starting the Naming_Service):

  ./EchoEventSupplier -ORBInitRef NameService=file://ns.ior -udp -ecname name1 -port 1233 -listenport 1234
  ./EchoEventSupplier -ORBInitRef NameService=file://ns.ior -udp -ecname name2 -port 1234 -listenport 1233

This will start two EC/supplier processes on the same node.  One (name1)
will listen on port 1234 and send on port 1233.  The other (name2) will
do the opposite. You should be able to use any available port as long as
the port and listenport options are symmetric (listenport of one process
must be the port of the other).  The -address option can be used to
specify a supplier/EC process on another host.  Here is an example of two
processes on different hosts:

On node1:
  ./EchoEventSupplier -ORBInitRef NameService=file://ns.ior -udp -ecname name1 -port 1233 -listenport 1234 -address node2
On node2:
  ./EchoEventSupplier -ORBInitRef NameService=file://ns.ior -udp -ecname name2 -port 1234 -listenport 1233 -address node1

When using UDP, this example is limited to federating two ECs.

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To start the supplier/EC processes and federate them using multicast, do the
following (after starting the Naming_Service):

./EchoEventSupplier -ORBInitRef NameService=file://ns.ior -ORBSvcConf supplier.conf -ecname name1 -address 224.9.9.2 -port 1234
./EchoEventSupplier -ORBInitRef NameService=file://ns.ior -ORBSvcConf supplier.conf -ecname name2 -address 224.9.9.2 -port 1234

The -address and -port options should be passed a valid and available
multicast address and port.

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To start the consumers, simply do the following (this works the same for
both types of federations):

./EchoEventConsumer -ORBInitRef NameService=file://ns.ior -ecname name1
./EchoEventConsumer -ORBInitRef NameService=file://ns.ior -ecname name2

It may be easiest to start these in separate windows.  Each consumer
connects to one EC (specified by the -ecname option).  You should see
events from both suppliers on each event channel (each supplier passes
events containing with the name of the EC they are using).

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EchoEventSupplerMain.cpp

  Main program for a PushSupplier.

    EchoEventSupplier [ -ORBSvcConf supplier.conf ] [ -udp ] -ecname <name>
                      [ -address <address> ] [ -port <port> ]
                      [ -listenport <lport> ]

  This will create a local RTEC event channel and bind it under
  the root context of the naming service with the name <name>.
  It will also federate with remote event channels specified via
  the other options.  By default, it uses multicast to federate
  the ECs (specifying -udp forces use of UDP).  <address> is
  the address of the remote EC when using UDP and the multicast
  address when using multicast.  <port> is the port to send
  to when using UDP and the multicast port when using multicast.
  <lport> is the port to listen on for UDP (and not used by
  multicast.  You must pass -ORBSvcConf supplier.conf when
  using multicast so as to enable Observers.

  After initializing the local event channel and setting up the
  connection for the federation, it publishes an event to the
  local event channel every 10 milliseconds.  This event will
  contain the string <name> in the any_value field.

  Use Control-C to kill the process.

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EchoEventConsumerMain.cpp

  Main program for a PushConsumer.

  To run it:

    EchoEventConsumer -ecname <name>

  This will look for an event channel bound to <name> in the Root context
  of the Naming Service.  It will consume events from this channel and
  print the type, source, and string contents contained in any_value.

  Use Control-C to kill the process.

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EchoEventConsumer_i.{h,cpp}

  Call which implements the RtecEventComm::PushConsumer interface.

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SimpleAddressServer.{h,cpp}

  This is a servant class that implements the RtecUDPAdmin::AddrServer
  interface.  It is used by the UDP/multicast senders to return an
  address that they will send out particular events on.  It is also
  used by the multicast event handler, to determine which addresses
  to listen to based on consumer subscriptions.  This simple
  implementation always returns the same address.



Exeuction via Perl Script
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A Perl script has been created to automate the steps shown
above.  This script can be run via the following command:

./run_test.pl

By default, this script uses multicast; pass -udp to the
script to use udp.