1
0
mirror of https://github.com/CumulusNetworks/ifupdown2.git synced 2024-05-06 15:54:50 +00:00
CumulusNetworks-ifupdown2/docs/source/developmentcorner.rst
Roopa Prabhu ff50f301d5 move ifupdown2/* .
ifupdown2 code was one level deeper because ifupdown2 initially
had ifupdown2 and ifupdown2-addons as two separate packages.
Since they were combined into one package, it makes sense to
move all combined code under the top level directory

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
2015-08-02 05:05:52 -07:00

73 lines
3.1 KiB
ReStructuredText

Development Corner
==================
Getting started
---------------
Unlike original ifupdown, all interface configuration is moved to external
python modules. That includes inet, inet6 and dhcp configurations.
* if you are looking at fixing bugs or adding new features to the ifupdown2
infrastructure package, pls look at the apiref, documentation and code
for python-ifupdown2
Writing a ifupdown2 addon module
--------------------------------
Addon modules are a nice way to add additional functionality to ifupdown2.
Typically a new addon module will include support for a new network interface
configuration which is not already supported by existing ifupdown2 addon
modules.
ifupdown2 addon modules are written in python. python-ifupdown2 package
comes with default addon modules. All addon modules are installed under
/usr/share/ifupdownaddons directory.
The center of the universe for an addon module is the 'class iface' object
exported by the python-ifupdown2 package.
The iface object is modeled after an iface entry in the user provided network
configuration file (eg. /etc/network/interfaces). For more details see
the api reference for the iface class.
ifupdown2 dynamically loads a python addon module. It expects the addon module
to implement a few methods.
* all addon modules must inherit from moduleBase class
* the module must implement a class by the same name
* the network interface object (class iface) and the operation to be performed
is passed to the modules. Operation can be any of 'pre-up', 'up', 'post-up',
'pre-down', 'down', 'post-down', 'query-check', 'query-running'.
The module can choose to support a subset or all operations.
In cases when the operation is query-check, the module must compare between
the given and running state and return the checked state of the object in
queryobjcur passed as argument to the run menthod.
* the python addon class must provide a few methods:
* run() : method to configure the interface.
* get_ops() : must return a list of operations it supports.
eg: 'pre-up', 'post-down'
* get_dependent_ifacenames() : must return a list of interfaces the
supported interface is dependent on. This is used to build the
dependency list for sorting and executing interfaces in dependency order.
* if the module supports -r option to ifquery, ie ability to construct the
ifaceobj from running state, it can optionally implement the
get_dependent_ifacenames_running() method, to return the list of
dependent interfaces derived from running state of the interface.
This is different from get_dependent_ifacenames() where the dependent
interfaces are derived from the interfaces config file (provided by the
user).
* provide a dictionary of all supported attributes in the _modinfo
attribute. This is useful for syntax help and man page generation.
python-ifupdown2 package also installs ifupdownaddons python package
that contains helper modules for all addon modules.
see example address handling module /usr/share/ifupdownaddons/address.py
API reference
-------------
.. toctree::
:maxdepth: 2
addonsapiref.rst
addonshelperapiref.rst