yangdump

README

YANG Schema Dump Tool (yangdump)

This simple golang tool will download the current version of YANG or YIN schema files from the target device using the NETCONF protocol.

Usage

yangdump -h <host> -u <userid> -p <password> -d <target directory> -yin

$ yangdump 
Usage of yangdump:
  -d string
    	Schema destination directory. (default ".")
  -h string
    	Hostname
  -p string
    	Password
  -u string
    	Username
  -k string
        SSH private key file.
  -yin
    	Download YIN format instead of YANG.

Building

A simple Makefile is included to build yangdump, otherwise, go build will get you there.

How does it work?

Using the ietf-netconf-monitoring schema as defined in RFC 6022 we issue a NETCONF get request to a device for a list of supported schema.

<get>
	<filter type="subtree">
		<netconf-state xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-monitoring">
			<schemas/>
		</netconf-state>
	</filter>
</get>

The device will return a list of schema available for download.

  <data>
    <netconf-state xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-monitoring">
      <schemas>
        <schema>
          <identifier>openroadm-augment</identifier>
          <version>2020-01-03</version>
          <format>yin</format>
          <namespace>http://coriant.com/yang/os/openroadm-augment</namespace>
          <location>NETCONF</location>
        </schema>
        <schema>
          <identifier>openroadm-augment</identifier>
          <version>2020-01-03</version>
          <format>yang</format>
          <namespace>http://coriant.com/yang/os/openroadm-augment</namespace>
          <location>NETCONF</location>
        </schema>
		...
      </schemas>
    </netconf-state>
  </data>

We then use get-schema operations defined in RFC 6022 to get the individual schema files listed on the device of format yang and location NETCONF.

<get-schema xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-monitoring">
	<identifier>openroadm-augment</identifier>
	<version>2020-01-03</version>
	<format>yang</format>
</get-schema>

If the -yin option is specified yangdump will download the XML YIN schema representation.

Notes

Structures for parsing the ietf-netconf-monitoring schema have been hand created using xml: annotations and not using a compiler such as that provide by tools such as ygot. The reason for this is that there are no golang tools for building XML parsers for NETCONF/XML, however is good support for NESTCONF/JSON. Unfortunately, Infinera only supports NETCONF/XML so XML parsers are required. Infinera does support RESTCONF/JSON, but does not support ietf-netconf-monitoring over RESTCONF.

Documentation

Overview

messages are the NETCONF protocol messages sent to a device to retrieve YANG/YIN schema as defined in ietf-netconf-monitoring.

schema contains a manual XML mapping for the ietf-netconf-monitoring YANG schema needed to download YANG/YIN schema stored on a device.

session contains functionality needed to download YANG/YIN schema as defined in ietf-netconf-monitoring.

yangdump will download the current version of YANG or YIN schema files from the target device using the NETCONF protocol.