M3-E-02.md

Module 3 Extra 02: NETCONF with Go - Edit Operations

Concept:

Using NETCONF to modify the configuration of SR Linux, focusing on <edit-config> and <commit> operations.

Challenge:

Write a Go program to change the name of the router and put a description in interface ethernet1-1 using NETCONF.

Code Example:

// main.go
package main

import (
	"context"
	"fmt"
	"log"
	"time"

	"github.com/nemith/netconf"
	ncssh "github.com/nemith/netconf/transport/ssh"
	"golang.org/x/crypto/ssh"
)

const sshAddr = "clab-srl-2-nodes-srl1:830"

func main() {
	config := &ssh.ClientConfig{
		User: "admin",
		Auth: []ssh.AuthMethod{
			ssh.Password("NokiaSrl1!"),
		},
		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
	}

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	transport, err := ncssh.Dial(ctx, "tcp", sshAddr, config)
	if err != nil {
		panic(err)
	}
	defer transport.Close()

	session, err := netconf.Open(transport)
	if err != nil {
		panic(err)
	}

	// timeout for the call itself.
	ctx, cancel = context.WithTimeout(ctx, 5*time.Second)
	defer cancel()

    configXML := `
	<system xmlns="http://openconfig.net/yang/system">
		<config>
			<hostname>srl12</hostname>
		</config>
	</system>
	<interface xmlns="urn:nokia.com:srlinux:chassis:interfaces">
		<name>ethernet-1/1</name>
		<admin-state>enable</admin-state>
		<description>Configured by NetAuto</description>
		<subinterface>
			<index>0</index>
			<admin-state>enable</admin-state>
			<ipv4>
				<address>
					<ip-prefix>10.0.0.1/24</ip-prefix>
				</address>
			</ipv4>
		</subinterface>
	</interface>`

	// Edit the configuration
	err = session.EditConfig(ctx, "candidate", configXML)
	if err != nil {
		log.Fatalf("Failed to edit config: %v", err)
	}
	fmt.Println("Configuration applied to candidate datastore.")

	// Commit the changes
	err = session.Commit(ctx)
	if err != nil {
		log.Fatalf("Failed to commit config: %v", err)
	}
	fmt.Println("Configuration committed successfully.")

	// Verify by getting the config again (optional)
	deviceConfig, err := session.GetConfig(ctx, "running")
	if err != nil {
		log.Fatalf("failed to get config aber commit: %v", err)
	}

	fmt.Println("--- Running Configuration ---")
	fmt.Printf("Config:\n%s\n", deviceConfig)

	if err := session.Close(context.Background()); err != nil {
		log.Print(err)
	}
}

Instructions:

1. Ensure your srl_2_nodes.clab.yaml is deployed.
2. Run go mod tidy.
3. Save the code as main.go.
4. Run go run main.go.

Further Readings

• https://github.com/nemith/netconf