YDK or YANG Development Kit is a Software Development Kit that provides API's that are modeled in YANG. The main goal of YDK is to reduce the learning curve by expressing the model semantics in API and abstracting protocol/encoding details. The API's are generated from YANG models found in this profile file https://github.com/CiscoDevNet/ydk-gen/blob/master/profiles/ydk/ydk_0_4_1.json using the ydk-gen tool https://github.com/CiscoDevNet/ydk-gen .

Linux

Ubuntu (Debian-based) - The following packages must be present in your system before installing YDK-Py:

$ sudo apt-get install python-pip zlib1g-dev python-lxml libxml2-dev libxslt1-dev python-dev

Mac

It is recommended to install homebrew (http://brew.sh) and Xcode command line tools on your system before installing YDK-Py:

$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
$ xcode-select --install

Create a source distribution:

$ cd <ydk_py_git_root>
$ python setup.py sdist

We recommend that you perform the installation under a Python virtual environment (virtualenv). To install virtualenv, execute:

$ pip install virtualenv

Create a new virtual environment:

$ virtualenv -p python2.7 ydk-py
$ source ydk-py/bin/activate

Install requirements:

(ydk-py)$ pip install -r requirements.txt

Install YDK-Py:

(ydk-py)$ pip install dist/ydk-0.4.1.tar.gz

• YANG Development Kit is a Python SDK that provides an API to access/modify configuration and operational entities that are modeled using YANG
• The modules under the package ydk.models are derived from YANG models
• YDK provides a simple CRUD (Create/Read/Update/Delete) api that allows the developer to perform these operations on entities on a server that supports them

In this example we are going to set some configuration on the openconfig bgp model. The complete sample is available in samples/bgp.py. The sample can be run with the below steps. :

(ydk-py)$ export PYTHONPATH=$PYTHONPATH:`pwd`
(ydk-py)$ python ./samples/bgp.py -h
Usage: bgp.py [-h | --help] [options]

Options:
-h, --help            show this help message and exit
-v VERSION, --version=VERSION
                    force NETCONF version 1.0 or 1.1
-u USERNAME, --user=USERNAME
-p PASSWORD, --password=PASSWORD
                    password
--proto=PROTO         Which transport protocol to use, one of ssh or tcp
--host=HOST           NETCONF agent hostname
--port=PORT           NETCONF agent SSH port

(ydk-py)$ python ./samples/bgp.py --host <ip-address-of-netconf-server> -u <username> -p <password> --port <port-number>

The first step in any application is create a 'Service Provider Instance'. 'Service Providers' are responsible for mapping between the CRUD service API and the underlying manageability protocol. In the current version of YDK we have one service provider which is the ydk.providers.NetconfServiceProvider . It maps the CRUD api's to netconf rpc.

In this example we instantiate an instance of the service provider that creates a netconf session to the machine at ip 10.0.0.1 :

from ydk.providers import NetconfServiceProvider

sp_instance = NetconfServiceProvider(address='10.0.0.1',
                                     port=830,
                                     username='test',
                                     password='test',
                                     protocol = 'ssh')

After establishing the connection, it's time to instantiate the entities and set some data.

First import the types from the module:

from ydk.models.bgp import bgp

Next set the attributes :

# create BGP object
bgp_cfg = bgp.Bgp()

# set the Global AS
bgp_cfg.global_.config.as_ = 65001

# Create an AFI SAFI config
ipv4_afsf = bgp_cfg.global_.afi_safis.AfiSafi()
ipv4_afsf.afi_safi_name = 'ipv4-unicast'
ipv4_afsf.config.afi_safi_name = 'ipv4-unicast'
ipv4_afsf.config.enabled = True

# Add the AFI SAFI config to the global AFI SAFI list
bgp_cfg.global_.afi_safis.afi_safi.append(ipv4_afsf)

First we need to import the CRUDService class:

from ydk.services import CRUDService

Next we instantiate the CRUDService:

crud_service = CRUDService()

And finally we invoke the create method of the CRUDService class passing in the service provider instance and our entity (bgp_cfg):

try:
    crud_service.create(sp_instance, bgp_cfg)
except YPYError:

Note if there were any errors the above API will raise YPYError.

Uses common Python logging. All modules are based off "ydk" log:

import logging
log = logging.getLogger('ydk')
log.setLevel(logging.DEBUG)
ch = logging.StreamHandler()
log.addHandler(ch)

The current release version is 0.4.1 (beta). YDK-Py is licensed under the Apache 2.0 License.

• Samples can be found under the <git_root>/samples directory
• API documentation can be found at http://ydk.cisco.com/py/docs
• Additional samples can be found at https://github.com/CiscoDevNet/ydk-py-samples
• For queries related to usage of the API, please join the YDK community at https://communities.cisco.com/community/developer/ydk