undefined method `chomp' for nil:NilClass

[tfluehmann]

Hello everyone

We have an issue every 200th time when we login into a cisco ios machine.
We get the following error:
undefined method `chomp' for nil:NilClass

["/home/safe/rails_projects/safe4/.bundle/ruby/2.2.0/gems/net-ssh-3.0.2/lib/net/ssh/prompt.rb:73:in `prompt'"
"/home/safe/rails_projects/safe4/.bundle/ruby/2.2.0/gems/net-ssh-3.0.2/lib/net/ssh/authentication/methods/password.rb:57:in `ask_password'"
"/home/safe/rails_projects/safe4/.bundle/ruby/2.2.0/gems/net-ssh-3.0.2/lib/net/ssh/authentication/methods/password.rb:22:in `authenticate'"
"/home/safe/rails_projects/safe4/.bundle/ruby/2.2.0/gems/net-ssh-3.0.2/lib/net/ssh/authentication/session.rb:79:in `block in authenticate'"
"/home/safe/rails_projects/safe4/.bundle/ruby/2.2.0/gems/net-ssh-3.0.2/lib/net/ssh/authentication/session.rb:66:in `each'"
"/home/safe/rails_projects/safe4/.bundle/ruby/2.2.0/gems/net-ssh-3.0.2/lib/net/ssh/authentication/session.rb:66:in `authenticate'"
"/home/safe/rails_projects/safe4/.bundle/ruby/2.2.0/gems/net-ssh-3.0.2/lib/net/ssh.rb:229:in `start'"

We are using net-ssh 3.0.2 and ruby 2.3.1.
It looks like the machine sends EOF and gets returns nil. Is it possible to implement a rescue in the prompt method?

      def prompt(prompt, echo=true)
        @seen_warning ||= false
        if !echo && !@seen_warning
          $stderr.puts "Text will be echoed in the clear. Please install the HighLine or Termios libraries to suppress echoed text."
          @seen_warning = true
        end

        $stdout.print(prompt)
        $stdout.flush
       $stdin.gets.chomp
end

Kind Regards
tfluehmann

[mfazekas]

See #366 #234

Can you detail the usecase? Do you use password auth? Or do you have key auth? I assume you have public key auth which fails in every 100th cases and falls back to password auth that tries to ask for password which fails because the stdin is redirected.

The error suggest that the app is non interactive and your stdin is redirected. You should be using the non_interactive option, so that no prompt will be asked.

[tfluehmann]

@mfazekas
We are using passwort authentication. We have currently no options set.
I will implement the non_interactive and test it for a while.

I haven't found the other issues while my research, I think can close this afterwards.

Thank you.

[mfazekas]

If you use non_interactive that means it will not ask for password, so might not be suitable for you

$stdin.gets only returns nil for end of file. Is this an interactive prompt? Is the user pressing ctrl+D?

[tfluehmann]

I can't say to be honest. But I exepect it to be, see here: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/sec_usr_ssh/configuration/15-e/sec-usr-ssh-15-e-book/sec-secure-shell-v2.html#GUID-5A1D0EE5-15BE-4F84-973F-E73FF4628C1A

We just ran into that case every few days but the script is running every 10 minutes. So I will be able to say if it fixed it probably in a few days.