Timeout for retrying initial ssh connection

[joshdk]

[codecov-io]

Codecov Report

Merging #118 into master will not change coverage. The diff coverage is 100%.

@@          Coverage Diff          @@
##           master   #118   +/-   ##
=====================================
  Coverage     100%   100%           
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  Files           1      1           
  Lines         107    129   +22     
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+ Hits          107    129   +22

Impacted Files	Coverage Δ
plugin.go	100% <100%> (ø)	:arrow_up:

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[joshdk]

The motivation behind this feature is that in our Drone build we dynamically provision a VM, then run commands on it for testing (see my comments here).

This VM is quickly "up" from a cloud infrastructure perspective, but it is often the case where SSHD needs an additional ~30 seconds to be functional. This PR adds an additional PLUGIN_RETRY_TIMEOUT value that allows a developer to specify how long to attempt to connect to the host for, retrying whenever a network error is encountered, with exponential backoff.

Basically prevents your entire build from turning red, just because your SSH daemon took a few seconds too long to start 😄

Cheers!

[joshdk]

@appleboy do you have any thoughts on this PR? I would be happy to hear any feedback you have 😄

[appleboy]

I will take this.