Examples needed for implementing contact routing patterns

[cwjohnston]

This is an issue with:

• Bug (site functionality or styling)
• Errata (fix needed for doc content)
• New content (guide wanted)
• Update (Add missing or refresh existing content)
• Enhancement (add new site functionality)

Expected Behavior

Documentation helps operators configure their Sensu instances to route notifications to the ideal first responders.

Current Behavior

Contact routing is possible using a combination of handlers and filters, but we need to solidify the required filters so we can provide a prescriptive guide.

Possible Solution

Implement a filter asset (library) which makes it easy to define filters which test for the presence of a named contact in a common check or entity label.

Context

Contact routing as implemented in Sensu Enterprise is a very useful tool for routing notifications to the ideal first responders, but its applications are limited to Sensu Enterprise's built-in integrations.

We believe that Sensu Go currently has all the pieces required to implement contact routing through a series of handlers and filters, but probably need to provide a library to make the pattern easy to implement.

[cwjohnston]

This gist includes some configuration sketches that seemed to be "mostly working" as we tried to prove out the handler+filters approach https://gist.github.com/cwjohnston/79f1810a95cde387846fcd8787622c07

[cwjohnston]

I translated that gist into a WIP project here https://github.com/cwjohnston/hasContact, still not working as expected.

[cwjohnston]

Tasks as I see them currently:

• Work with engineering to get a proof of concept filter asset working
• Polish the proof of concept filter asset and get it published to bonsai
• Document how to use filter asset in conjunction with a handlers + event filter definitions to implement contact routing pattern
• Move cwjohnston/sensu-go-has-contact-filter repo to sensu org

[cwjohnston]

The experimental has-contact-filter library asset is now on bonsai: https://bonsai.sensu.io/assets/cwjohnston/sensu-go-has-contact-filter

I've started a PR for a real readme here: sensu/sensu-go-has-contact-filter#7

In my view there's an open question as to how much of this readme belongs in our docs vs the filter library repository. Any thoughts?