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.