Ability to work with Instances over SSH tunnel.

[EYurchenko]

Inspired by:
#294
#933

In your .kitchen.yml file you use:

transport:
  name: ssh
  ssh_gateway: <gateway>
  ssh_gateway_username: <username at the gateway>

and all ssh operations will be tunnelled through this .
Basically we replace Net::SSH session in transport/ssh.rb with Net::SSH::Gateway, since this moment all ssh operations go through the tunnel. Remote end 'not being ready' also reported correctly:

local@ey-test-kitchen:~/test-kitchen-ey$ bundle exec kitchen converge -l debug
-----> Starting Kitchen (v1.10.2)
D      Berksfile found at /home/local/test-kitchen-ey/Berksfile, loading Berkshelf
D      Berkshelf 4.3.5 library loaded
-----> Creating <default-centos-7>...
D      [SSH] opening connection to local@10.236.62.20<{:user_known_hosts_file=>"/dev/null", :paranoid=>false, :port=>22, :compression=>false, :compression_level=>0, :keepalive=>true, :keepalive_interval=>60, :timeout=>15}> via eyurchenko@10.236.11.190
D      [SSH] connection failed (#<Net::SSH::ConnectionTimeout: timeout during server version negotiating>)
       Waiting for SSH service on 10.236.62.20:22, retrying in 3 seconds
D      [SSH] opening connection to local@10.236.62.20<{:user_known_hosts_file=>"/dev/null", :paranoid=>false, :port=>22, :compression=>false, :compression_level=>0, :keepalive=>true, :keepalive_interval=>60, :timeout=>15}> via eyurchenko@10.236.11.190
D      [SSH] local@10.236.62.20<{:user_known_hosts_file=>"/dev/null", :paranoid=>false, :port=>22, :compression=>false, :compression_level=>0, :keepalive=>true, :keepalive_interval=>60, :timeout=>15}> (echo '[SSH] Established')
       [SSH] Established
D      SSH ready on <default-centos-7>
...

[mwrock]

Would be great if we could reuse the retry logic accross the two connection strategies.

[EYurchenko]

I tried. Look at this commit d171410. But rubocop was very unhappy -(

[mwrock]

Looks like you hat the gateway and non-gateway connection with the retry all in one method there. I think you did the right thing be making separate methods but I'd suggest extracting the retry logic which appears to be identical in both to be something like:

def retry_connection(opts)
  yield
# RESCUE CODE HERE
end

Then

def establish_connection_via_gateway(opts)
  retry_connection(opts) do
    Net::SSH::Gateway.new(ssh_gateway,
        ssh_gateway_username, options).ssh(hostname, username, options)
  end
end

[EYurchenko]

Thanks for the hint! Moved the code. Although now we have comments describing parameters identical for three methods -(

[mwrock]

👍

[cheeseplus]

+1