DCE Python Scripts

Currently DCE includes an experimental support to the Python language. To enable it, you may need to recompile it with the flags:

--with-pybindgen=HERE_THE_PYBINDGEN_PATH

indicating the path to an existing Pybindgen source tree to use. Or in case waf didn’t find the interpreter, you can try to use the flags:

--with-python=HERE_THE_PYTHON_PATH

The first thing you may want to do is to import the DCE module. For example a minimal DCE script in Python could be:

from ns.DCE import *
print "It works!"

A first example

In this example, DCE executes a program running ten seconds on a single node.

# DCE import
from ns.DCE import *
# ns-3 imports
import ns.applications
import ns.core
import ns.network

# Increase the verbosity level
ns.core.LogComponentEnable("Dce", ns.core.LOG_LEVEL_INFO)
ns.core.LogComponentEnable("DceManager", ns.core.LOG_LEVEL_ALL)
ns.core.LogComponentEnable("DceApplication", ns.core.LOG_LEVEL_INFO)
ns.core.LogComponentEnable("DceApplicationHelper", ns.core.LOG_LEVEL_INFO)

# Node creation
nodes = ns.network.NodeContainer()
nodes.Create(1)

# Configure DCE
dceManager = ns.DCE.DceManagerHelper()
dceManager.Install (nodes);
dce = ns.DCE.DceApplicationHelper()

# Set the binary
dce.SetBinary ("tenseconds")
dce.SetStackSize (1<<20)
# dce.Install returns an instance of ns.DCE.ApplicationContainer
apps = dce.Install (nodes )
apps.Start ( ns.core.Seconds (4.0))

# Simulation
ns.core.Simulator.Stop (ns.core.Seconds(20.0))
ns.core.Simulator.Run ()
ns.core.Simulator.Destroy ()
print "Done."

You can then run the example with “waf –pyrun ...”

./waf --pyrun PATH_TO_YOUR_SCRIPT_HERE

or attach gdb to the python script:

./waf shell
gdb python -ex "set args PATH_TO_YOUR_SCRIPT_HERE" -ex "handle SIGUSR1 nostop noprint"

Limitations

The DCE Python bindings does not currently match completely the C++ API of DCE. The following classes are supported:

Class	Methods
DceApplication	GetPid, SetArguments, SetBinary, SetEgid, SetEnvironment, SetEuid, SetGid, SetStackSize, SetStdinFile, SetUid
DceApplicationHelper	AddArgument, AddArguments, AddEnvironment, Install, InstallInNode, ParseArguments, ResetArguments, ResetEnvironment, SetBinary, SetEgid, SetEuid, SetGid, SetStackSize, SetStdinFile, SetUid, GetPid
ProcStatus	GetCmdLine, GetExitCode, GetNode, GetPid, GetRealDuration, GetRealEndTime, GetRealStartTime, GetSimulatedDuration, GetSimulatedEndTime, GetSimulatedStartTime
DceManagerHelper	GetProcStatus, GetVirtualPath, Install, SetAttribute, SetVirtualPath
Ipv4DceRoutingHelper	Copy, Create
LinuxStackHelper	Install, InstallAll, RunIp, SetRoutingHelper, SysctlGet, SysctlSet