Add timout to ssh

[maikia]

Adds a timeout to curl and handles the exceptions in case there are any errors with subprocess output (before the connection just hanged sometimes stopping the work of the whole dispatcher).

The problem which remains and I don't know how to approach is that even if the connection is not established after (what is set now) 9 tries, with initial time 1sec doubled after each next try (ie max waiting time 8.51 min) the only thing we are able to return is either that the instance finished or not (ie True or False). If for any reason the instance is lost (shutting by hand, other scenarios (??) ) it will still try connecting to it the next time again.

This might be a problem for another PR though..

[codecov]

Codecov Report

Merging #467 (ac76a37) into master (4ac7ce0) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #467   +/-   ##
=======================================
  Coverage   93.46%   93.47%           
=======================================
  Files          99       99           
  Lines        8385     8393    +8     
=======================================
+ Hits         7837     7845    +8     
  Misses        548      548           

Impacted Files	Coverage Δ
ramp-engine/ramp_engine/tests/test_aws.py	63.33% <100.00%> (+3.57%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fe29f0c...075d281. Read the comment docs.

[lucyleeow]

Any idea why the connection to AWS just hangs some times? If it hangs here, maybe it will for other subsequent ssh requests we send to?

[lucyleeow]

Suggested change

	logger.error('Unhandled exception happend when checking if there'
	f' is an instance action: {e}')
	logger.error('Unhandled exception occurred when checking for '
	f'instance action: {e}')

[maikia]

thanks for your review @lucyleeow

Yes. I spent quite some time investigating the whole hanging issue. It seems that curl was hanging for now, but there is always a possibility it will hang elsewhere as well.

What other places would you suggest we need to take care of before making release?

[maikia]

Thanks @lucyleeow