Add timeout to tty_netconf.open

[shermdog]

There are situations where trying to open netconf via telnet hangs (such as if the session is in config mode).

Add timeout here to bail out if the netconf session doesn't start.

[dgjnpr]

+1 FYI @vnitinv

I recently hit this bug but for a different reason. It seems that sometimes the tty session does not "see" the first two XML comment lines when the netconf session is initiated. As such it hangs forever.

Given these comment lines are not strictly necessary I recommend a search for the "" tag that is part of the protocol.

I'm happy to run a debug release to triage what is really being returned by the device. I did look at doing this myself but it is beyond my current python skills.

[r2600r]

The hang is result of while True: loop located in many places. I had included timeout interval in my branch which now successfully break the infinite loop.

[dharpatel]

I had the same issue which @dgjnpr has. So as @r2600r respond on this issue I have change the code and try to use that updated code. But then I am getting error like "Netconify Error: netconf not responding". So @r2600r do you have any idea about this error?

[r2600r]

Dharpatel,that error means that netconify receive expected output from the device in specified time, 15 seconds. Enable flag for the detail output mode "--verbose 2". Netconify waits for "<!--" string, which is the beginning of the xml command output.