multiple commands in one ssh session

[Dominik Link]

Hi

I would like to run multiple ssh commands within the same 'context' as if it would be using putty when connecting to a cisco device.

Here are two examples of what i would need to send to the device:

1) Setting the terminal width to 0 in order to remove the line breaks. This makes parsing the output of the following command easier.

Switch#terminal width 0
Switch#show vlan brief

    VLAN Name                             Status    Ports
    ---- -------------------------------- --------- -------------------------------
    1    default                          active    Et0/0, Et0/1, Et0/2, Et0/3
    ...
    ...

2) Configure an IP address of an interface. When connecting with ssh, I start in the 'enable' mode due to the user privileges. I need to get in the config mode first. Afterwards, I need to get in the interface config mode and can finally set the address.

Router#configure terminal
    Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#interface e3/2
Router(config-if)#ip address 172.16.1.1 255.255.255.0

I can run a single command easily with session.Run() but as I described, I need to be able to run multiple commands and parse their output within a single 'context'.

How could this behavior be achieved with crypto/ssh? When I try to create a new session after the first session.run(), it always returns with an error: "EOF".

I just wanted to try whether the context will stay the same but it won't even come that far.

//create session 1 and go into config mode
session, err = client.NewSession()
if err != nil {
    panic("Failed to create session: " + err.Error())
}
if err := session.Run("conf t"); err != nil {
    panic("Failed to run: " + err.Error())
}
session.Close()

//create session 2 and go into if mode
session, err = client.NewSession()
if err != nil {
    //Error will be EOF
    panic("Failed to create session: " + err.Error())
}
if err := session.Run("int e3/2"); err != nil {
    panic("Failed to run: " + err.Error())
}
session.Close()







Thanks,

Dominik

I also posted this question in stackoverflow

[Matt Harden]

Instead of session.Run, use session.Shell. To interact with the shell, you will need to connect to at least Stdin, probably using StdinPipe() (NOTE I left out error handling):

session, err := client.NewSession()
in, err := session.StdinPipe()
out, err := session.StdoutPipe()
session.Stderr = out  // this will send stderr to the same pipe
err = session.Shell()
go readOutput(out)  // run a function to read the output of the commands

// send the commands
err = fmt.Println(in, "conf t")
// probably wait for the right output before continuing
//  - this requires synchronization with the readOutput goroutine
err = fmt.Println(in, "int e3/2")
// and so on
const ctrlZ = byte(25)
err = in.Write([]byte{ctrlZ})

I hope this helps!

--
You received this message because you are subscribed to the Google Groups "golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[hil...@gmail.com]

Hi Dominik. Have you finally found the solution? I'm working on similar task to run commands on cisco routers. Could you share you code for this?

[Matt Harden]

Did you try out my suggestion in reply to Dominik, namely to use session.Shell instead of session.Run?

--