Enable alerts definitions using web sessions

[josejulio]

• Aggregated (active/expired/rejected) web sessions

https://issues.jboss.org/browse/HAWKULAR-1255

[josejulio]

@miq-bot add-label providers/middleware

[josejulio]

@lucasponce Can you please take a look?

[lucasponce]

@josejulio It looks good to me.
I have one doubt if web sessions metrics should have two conditions or just a simple threshold is enough.
I personally like to have a single condition (choosing the operator), to define a condition when expired matches the operator instead to chain two.
i.e.
An alert when web sessions > 40 or web session < 10 is confusing to me, as you would expect two different alerts on this case (I think).

But, I guess this should be confirmed by @abonas or John Doyle.

If there is not a clear requeriment, I would go for a single condition, it's easier and the same semantic can be implemented with two alerts (and I think as a user it will be more meaningful).

[lucasponce]

Also, alerting offers more possibilities like range or rates conditions,

http://www.hawkular.org/docs/rest/rest-alerts-v1.html#Condition

But for a first introduction in MiQ of this feature I think a threshold can be enough.

[josejulio]

@lucasponce updated the PR with your suggestions.
Also it nows depends on:
ManageIQ/manageiq-ui-classic#2309 and ManageIQ/manageiq-providers-hawkular#68

[miq-bot]

This pull request is not mergeable. Please rebase and repush.

[josejulio]

@aljesusg please review

[miq-bot]

Checked commit josejulio@166116a with ruby 2.3.3, rubocop 0.47.1, and haml-lint 0.20.0
1 file checked, 0 offenses detected
Everything looks fine. 🍰

[aljesusg]

LGFM @josejulio

[josejulio]

Thanks, @chessbyte, can you review? thanks!

[chessbyte]

@abonas will review after your 👍

[abonas]

@miq-bot add_label alerts