[wp-meta] [Making WordPress.org] #6405: Migrate the `/here` command to use the Slack Messaging API

[Making WordPress.org]

#6405: Migrate the `/here` command to use the Slack Messaging API
----------------------------+--------------------
 Reporter:  dd32            |      Owner:  (none)
     Type:  task (blessed)  |     Status:  new
 Priority:  high            |  Milestone:
Component:  Slack & IRC     |   Keywords:
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 Due to some Slack API changes, it's not uncommon for the `/here` API to
 take more than 3,000ms between the API being called, and the response
 being sent.

 This results in errors shown in slack to the user of:
 {{{
 /here failed with the error "operation_timeout"
 }}}

 This is both confusing, and bad UX.

 Slacks APIs have changed to include a `response_url` webhook in the slash
 webhook payloads.
  - Slack sends webhook
  - We respond instantly with a 200, and a `Processing...` message
  - We process the data, crunch the numbers, send announcements
  - We make a webhook call to Slack on the `response_url` url, which
 updates the `Processing...` message to `Done! Your announcement has been
 made` or `Sorry, you can't use /here here, but you can use it in ....`
 error.

 This change in flow will result in the slack user not seeing the
 operation_timeout error, and avoid needless confusion (Since the
 announcement is made, usually just after the timeout).

-- 
Ticket URL: <https://meta.trac.wordpress.org/ticket/6405>
Making WordPress.org <https://meta.trac.wordpress.org/>
Making WordPress.org