Python Bindings

This section describes how generate the DCE Python bindings. The intended audience are the DCE developers, not the users willing to make simulations. People not interested in adding new public API can ignore this section, and read the chapter DCE Python Scripts.

Waf configuration scripts generate the Python bindings in a semi-automatic way. They use PyBindGen to generate a Python script template. This script needs to be manually updated. This intermediate script will generate a C++ source file that can be then compiled as a shared object, installed and imported by the Python scripts.

Step by Step

Step 1: Api scan

In this step, Waf calls PyBindGen to analyze the DCE public reference headers, in order to generate a temporary template Python file, that will generate a C++ file.

./waf --apiscan

Step 2: Pybindgen script update

The Pyhon script generated in the first step needs to be adjusted and renamed as ns3_module_dce.py. In particular to reduce the coupling with the ns-3 installation the waf configuration has been simplified. For this reason you need to paste the correct references for the ns-3 exported symbols, as for example:

module.add_class('Object', import_from_module='ns.core')
module.add_class('Node', import_from_module='ns.network')
module.add_class('NodeContainer', import_from_module='ns.network')

Step 3: C++ source code generation

ns3_module_dce.py can directly generate a C++ file for the Python module: ns3_module_dce.cpp. It should be added to the code revision system and included in the distribution. It just requires an installed recent version of Pybindgen.

Step 4: Compilation

In the compilation phase, wscript (the Waf installation module), compiles ns3_module_dce.cpp and generate a shared object called dce.so. This is the Python binding module.

./waf
./waf install

Configuration parameters

waf configuration flags:

--disable-python
	Don’t build Python bindings.
--apiscan	Rescan the API for Python bindings. Needs working GCCXML / pygccxml environment.
--with-pybindgen=WITH_PYBINDGEN
	Path to an existing Pybindgen source tree to use.
--with-python=WITH_PYTHON
	Path to an existing Pyhton installation