Dynamic Priority and Responder, $EventUri property for Handlebars template

[MattMofDoom]

Hi @nblumhardt ,

This pull request is a follow-on to #1 and with reference to https://github.com/datalust/seq-tickets/issues/1221

The enhancement adds an optional ability to specify event property names that can map to the Responder and Priority field.

• The Priority property mapping is tied to @Level by default - however a mapping must be specified to enable this.
• The mapped priorities translate the expected values to OpsGenie priorities - for example, Highest or Critical to P1.
• Unmatched priorities have a default priority value to fall back on
• For Responder property mapping, this leverages the existing ability to set a Name=Type comma separated string as a mapping.
• I don't currently implement a default for an unmatched mapping, although we could assume that a string without = separator denotes a team.

The value of this extension is that it can better tie structured properties to alerts. As an example, I could have a column from events ingested via https://www.nuget.org/packages/Seq.Input.MSSql/ tied directly to Priority, or at its simplest, have events with @Level = Critical raise a P1, @Level = Error raise a P2, @Level = Information raise a P3.

Responder is probably more forward looking in terms of utility. If my suggestion for dashboard alerts were implemented, it would fit neatly with this; however it also provides opportunity for unforeseen usages - I might decide to implement it in a Seq app and then be able to have it automatically pass through to OpsGenie.

I also extend the Handlebars Template to natively provide $EventUri - a link to the event - for convenience.

Finally, I have made the matching of property keys case-insensitive, with logic to exit the required loop as early as possible, and switched string comparisons to OrdinalIgnoreCase.

Cheers,

Matt

[nblumhardt]

Hi @MattMofDoom - looks great! The "mapping" syntax/convention is really nice :+1:

I have a few stylistic comments but it will be an order of magnitude quicker for me to check out a branch and let Rider work its reformatting magic than it will be to write it up here :-), so I'll merge as it is and tinker with it on dev 👍

[MattMofDoom]

@nblumhardt Awesome, thanks :-) I don't have licensing for any Jetbrains goodies so sounds great.