handler-slack.rb: implement a retry-timeout strategy for contacting s…

[kali-brandwatch]

…lack webhook

In certain scenarios the slack webhook delivery might fail due to several reasons:

• network issues
• rate limit exceeded
• internal server errors on slack api side

On those cases the call to the webhook might fail and our message not get delivered, or worse, it can leave our handler hanging for too long.

This commit implements a customizable retry strategy that tries to deliver the message several times to the webhook, with a timeout to do so. It also implements a sleep time in between retries. All of these 3 settings can be customized in the json config of the handler, with defaults to 5 retries with 5 second sleeps in between, and 10 seconds timeout for each try.

This should incidentally solve issue #15

Pull Request Checklist

Is this in reference to an existing issue?

General

• [ ] Update Changelog following the conventions laid out here

• [ ] Update README with any necessary configuration snippets

• [ ] Binstubs are created if needed

• [ ] RuboCop passes

• [ ] Existing tests pass

New Plugins

• [ ] Tests

• [ ] Add the plugin to the README

• [ ] Does it have a complete header as outlined here

Purpose

Known Compatibility Issues

[kali-brandwatch]

I have added a new commit to fix the issues rubocop was complaining about but travis doesn't seem to launch a new build automatically...

[kali-brandwatch]

I have added a new commit to fix the issues rubocop was complaining about but travis doesn't seem to launch a new build automatically...

Sorry, it did, I was not looking properly. It seems I just missed one of rubocop's complaints.... my bad

[majormoses]

Sorry for the delay this fell off my radar, thanks for putting this together. I will work on cutting a release.

[majormoses]

released: https://rubygems.org/gems/sensu-plugins-slack/versions/4.1.0

[kali-brandwatch]

Thanks!