examples: adding some basic examples

 * consumer/producer
 * ndnping
 * traffic generator
 * catchunks/putchunks

Change-Id: Ie4c37f08f29a945f2fb1ce0b4d36da1bfb3edd3b
diff --git a/examples/traffic_generator.py b/examples/traffic_generator.py
new file mode 100644
index 0000000..48bbd07
--- /dev/null
+++ b/examples/traffic_generator.py
@@ -0,0 +1,105 @@
+# -*- Mode:python; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+#
+# Copyright (C) 2015-2021, The University of Memphis,
+#                          Arizona Board of Regents,
+#                          Regents of the University of California.
+#
+# This file is part of Mini-NDN.
+# See AUTHORS.md for a complete list of Mini-NDN authors and contributors.
+#
+# Mini-NDN is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Mini-NDN is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Mini-NDN, e.g., in COPYING.md file.
+# If not, see <http://www.gnu.org/licenses/>.
+
+
+"""
+This example demonstrates the functionality of the Traffic generator. It consists of a traffic
+server and client. The server will listen for interest on the prefix specified in the server
+configuration file. The client will send a designated number of interests to the server and 
+get the data back.
+More details on traffic generator here: https://github.com/named-data/ndn-traffic-generator
+"""
+
+from time import sleep
+
+from mininet.log import setLogLevel, info
+from minindn.minindn import Minindn
+from minindn.util import MiniNDNCLI
+from minindn.apps.app_manager import AppManager
+from minindn.apps.nfd import Nfd
+from minindn.apps.nlsr import Nlsr
+from minindn.util import copyExistentFile
+from examples.nlsr.nlsr_common import getParser
+
+def trafficServer(node, serverConfFile):
+    """
+    Start traffic server
+     :parma mininet.node.Host node: mininet node object
+     :param string serverConfFile: server configuration file
+    """
+    info ("Starting traffic server \n")
+    # c = 10, i.e maximum number of Interests to respond
+    cmd = 'ndn-traffic-server -c {} {} &> traffic-server.log &'.format(10, serverConfFile)
+    node.cmd(cmd)
+    sleep(10)
+
+    # The server configuration file uses /example prefix to advertise its service
+    # thus, server needs to advertise this prefix for the client to reach it
+    serverPrefix = "/example"
+    server.cmd('nlsrc advertise {}'.format(serverPrefix))
+    sleep(5) # sleep for routing convergence
+
+def trafficClient(node, clientConfFile):
+    """
+    Start traffic client
+     :parma mininet.node.Host node: The expiration period in milliseconds, or None if not specified.
+     :param string clientConfFile: client configuration file
+    """
+    info ("Starting ndn traffic client \n")
+    # c = 10, total number of Interests to be generated each at 200ms interval
+    cmd = 'ndn-traffic-client -c {} -i {} {} &>  traffic-client.log &'.format(10, 200, clientConfFile)
+    node.cmd(cmd)
+
+if __name__ == '__main__':
+    setLogLevel('info')
+
+    # Traffic generator configuration files. For this example, we are using default conf files.
+    # More details on configuration files here: https://github.com/named-data/ndn-traffic-generator
+    possibleServerConfPath = ["/etc/ndn/ndn-traffic-server.conf.sample", "/usr/local/etc/ndn/ndn-traffic-server.conf.sample"]
+    possibleClientConfPath = ["/etc/ndn/ndn-traffic-client.conf.sample", "/usr/local/etc/ndn/ndn-traffic-client.conf.sample"]
+
+    Minindn.cleanUp()
+    Minindn.verifyDependencies()
+    ndn = Minindn(parser=getParser())
+    ndn.start()
+
+    nfds = AppManager(ndn, ndn.net.hosts, Nfd)
+    nlsrs = AppManager(ndn, ndn.net.hosts, Nlsr)
+    sleep(90)
+
+    # Default topology is used in this experiment "/topologies/default-topology.conf"
+    # lets make node "a" as a traffic-server node, and node "c" as a traffic-client node
+    server  = ndn.net['a']
+    client = ndn.net['c']
+    serverConf = '{}/{}/server-conf'.format(ndn.args.workDir, server.name)
+    clientConf = '{}/{}/client-conf'.format(ndn.args.workDir, client.name)
+
+    copyExistentFile(server, possibleServerConfPath, serverConf)
+    copyExistentFile(server, possibleClientConfPath, clientConf)
+
+    trafficServer(server, serverConf)
+    trafficClient(client, clientConf)
+    # default location for the results: /tmp/minindn/
+
+    MiniNDNCLI(ndn.net)
+    ndn.stop()