How to retrieve the interface configuration

The "nc-read-xr-ifmgr-cfg-11-ydk.py", the process is just "pass" 

def process_interface_configurations(interface_configurations):

    """Process data in interface_configurations object."""

    pass 

Tried to modify a bit but got the response "None". 

def process_interface_configurations(interface_configurations):

    """Process data in interface_configurations object."""

    int=interface_configurations.InterfaceConfiguration()

    print ('interface name: ',int.interface_name) 

I believe it should be a list of configuration... but don't know how it should be...

any sample can be reference.

All basic sample apps in the range of 10-19 are boilerplates (templates).  Those boilerplates do no processing and provide no output.  The convention should be described in the README:

ydk-py-samples/samples/basic at master · CiscoDevNet/ydk-py-samples · GitHub 

Now, for a sample implementation of processing interface config, here's a very simple function to print the interface names: 

def process_interface_configurations(interface_configurations):
    """Process data in interface_configurations object."""
    for interface_configuration in interface_configurations.interface_configuration:
      print(interface_configuration.interface_name) 

The entire configuration hierarchy is documented at:

http://ydk.cisco.com/py/docs/gen_doc_6bcc931a236e23d2877d3e742c4a01f5adc17782.html 

The function above produces the following output when the script is run against one of my routers:

 Loopback0

MgmtEth0/RP0/CPU0/0
GigabitEthernet0/0/0/0
GigabitEthernet0/0/0/1

• Is there a way to read all configurations under a specific interface.

# create read filter for mgmt interface
interface_configurations = xr_ifmgr_cfg.InterfaceConfigurations()
interface_configuration = interface_configurations.InterfaceConfiguration()
interface_configuration.interface_name ="MgmtEth0/RP0/CPU0/0"
interface_configurations.interface_configuration.append(interface_configuration)

# read data from NETCONF device
interface_configurations = crud.read(provider, interface_configurations) 

Actually, you can be more clever and just instantiate the class that defines an interface.  YDK will do the right thing and build the proper filter with the full hierarchy even though you are reading a more specific object: 

# create read filter for mgmt interface
interface_configuration = xr_ifmgr_cfg.InterfaceConfigurations.InterfaceConfiguration()
interface_configuration.interface_name ="MgmtEth0/RP0/CPU0/0"

# read data from NETCONF device
interface_configuration = crud.read(provider, interface_configuration) 

Let's say we just want to print the interface description once read:

print(interface_configuration.description) 

Here's a sample output on a mgmt interface with an obvious description:

$ ./nc-read-xr-ifmgr-cfg-99-ydk.py ssh://admin:admin@router

*** MANAGEMENT INTERFACE ***

$ 

Here's the full app log:

$ ./nc-read-xr-ifmgr-cfg-99-ydk.py ssh://admin:admin@router -v

2016-12-13 14:44:10,148 - ydk.providers.netconf_provider - INFO - NetconfServiceProvider connected to router:None using ssh

2016-12-13 14:44:10,211 - ydk.services.crud_service - INFO - READ operation initiated

2016-12-13 14:44:10,213 - ydk.providers._provider_plugin - DEBUG -

<rpc xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="urn:uuid:63dbbab9-2cce-48e8-8437-832206be1989">

  <get>

    <filter type="subtree">

      <interface-configurations xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ifmgr-cfg">

        <interface-configuration>

          <interface-name>MgmtEth0/RP0/CPU0/0</interface-name>

        </interface-configuration>

      </interface-configurations>

    </filter>

  </get>

</rpc> 

2016-12-13 14:44:10,277 - ydk.providers._provider_plugin - DEBUG -

<rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" message-id="urn:uuid:63dbbab9-2cce-48e8-8437-832206be1989">

  <data>

    <interface-configurations xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ifmgr-cfg">

      <interface-configuration>

        <active>act</active>

        <interface-name>MgmtEth0/RP0/CPU0/0</interface-name>

        <description>*** MANAGEMENT INTERFACE ***</description>

        <ipv4-network xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ipv4-io-cfg">

          <addresses>

            <primary>

              <address>10.30.110.82</address>

              <netmask>255.255.254.0</netmask>

            </primary>

          </addresses>

        </ipv4-network>

      </interface-configuration>

    </interface-configurations>

  </data>

</rpc-reply> 

2016-12-13 14:44:10,278 - ydk.services.crud_service - INFO - READ operation completed

*** MANAGEMENT INTERFACE ***

2016-12-13 14:44:10,500 - ydk.providers.netconf_provider - INFO - NetconfServiceProvider disconnected from router using ssh

$

• How do you print the whole XML interface in a single print statement.. Similar to what is in the rpc-reply data group.

• Tried but they are not working so well for me.
•  tried the examples:
•   cd-encode-xr-ifmgr-cfg-10-ydk.py
•   cd-encode-xr-ifmgr-cfg-11-ydk.py 
• Have uncommented the print statement in each, ran similar to: (like README example says to) 
• cd-encode-xr-ifmgr-cfg-11-ydk.py ssh://jb:password@abc.123 
• And get:
• usage: cd-encode-xr-ifmgr-cfg-11-ydk.py [-h] [-v]
• cd-encode-xr-ifmgr-cfg-11-ydk.py: error: unrecognized arguments: ssh://jb:password@abc.123 
• Running the script, as is, gives me simply this output:
• <interface-configurations xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ifmgr-cfg"/> 
• Also, if I'm looking for decode, I'm seeing no examples.

 ./cd-encode-xr-ifmgr-cfg-11-ydk.py  # <-- no need for credentials

ydk-py-samples/cd-encode-xr-ifmgr-cfg-36-ydk.py at master · CiscoDevNet/ydk-py-samples · GitHub

and it's XML output:

ydk-py-samples/cd-encode-xr-ifmgr-cfg-36-ydk.xml at master · CiscoDevNet/ydk-py-samples · GitHub

 As the help string indicates, the codec sample apps take no argument to connect to a device.  These apps only encode a Python object into XML and print the resulting string.  Hope this clarifies. 

 It would be like ...

1. set the provider variable with router info, username, password

2. set interface filter

3. then print like:   print( <????>(provider, interface_configurations))

• this would print out the complete router's interface, or whatever I've may have filtered on... like a specific interface-name.

If you're looking at an XML-centric use case, it may be that an approach other than the YDK is what you're looking for. For example, you might want to use the ncclient library directly. You can see samples of how to use ncclient here: 

https://github.com/CiscoDevNet/ncc 

You can see sample filters to use with the script ncc.py at: 

https://github.com/CiscoDevNet/ncc/tree/master/snippets/filters 

These are just standard netconf subtree filters that can be used with get/get_config from ncclient, as shown in the script ncc.py.

You can get the interface by using the following or similar XML via netconf session: 

<?xml version="1.0" encoding="UTF-8"?>

<rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">

     <get-config>

     <source><running/></source>

          <filter>

               <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">

                    <interface></interface>

               </interfaces>

          </filter>

</get-config>

</rpc>]]>]]> 

That should give you an xml configuration which contains information about interfaces.

If you are using ncclient on python, you can make a variable containing the filter part of the xml (highlighted in bold above) and use it on ncclient 

Example (assuming my_nc as ncclient instance that is already connected to your router)

my_filter= """

          <filter>

               <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">

                    <interface></interface>

               </interfaces>

          </filter>

            """

result = my_nc.get_config("running", my_filter) 

You can then parse result to get the info that you want. Python has a lot of module dealing with xml (minidom, elementree, xmltodict...) 

For example, this one will give you an indented XML view of the result 

     report = xml.dom.minidom.parseString(result.xml)

     print(report.toprettyxml()) 

https://github.com/CiscoDevNet/ncc/tree/master/notebooks

Do not have IOS-XR. I uploaded my sample script at https://github.com/snakeskinsalamander/Netconf-example just in case. It is using an always-on XE on devnet sandbox though.
This is as simple as you could make a call to get interface information into an XML output using Python and the ncclient. 

#!/usr/bin/env python

import sys

from ncclient import manager

from lxml import etree 

if __name__ == '__main__': 

    omg = '<interface-configurations xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ifmgr-cfg"/>' 

    m =  manager.connect(host="my.router.com",

                         port="830",

                         username="me",

                         password="password",

                         device_params={'name':"csr"})

    data = m.get_config("running",'<filter>'+omg+'</filter>')

    print etree.tostring(etree.fromstring(data.xml), pretty_print=True)

 took this right from the #10 example above.

    filter = '''<bgp xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ipv4-bgp-oper">

                <instances>

                <instance>

                <instance-name>default</instance-name>

                <instance-active>

                <vrfs>

                <vrf>

                 <vrf-name/>

                 <afs>

                    <af>

                      <af-name>ipv4-unicast</af-name>

                      <networks>

                        <network>

                          <network/>

                          <local-process-instance-path>

                            <attributes-after-policy-in>

                              <common-attributes>

                                <extended-community/>

                              </common-attributes>

                            </attributes-after-policy-in>

                          </local-process-instance-path>

                        </network>

                      </networks>

                    </af>

                  </afs>

                </vrf>

                </vrfs>

                </instance-active>

                </instance>

                </instances>

                </bgp>

             ''' 

When dealing with netconf/yang on IOS-XR, subtree filtering is the only query syntax supported. No timelines for support of XPath filtering at this time, and no other standardised alternative.