doc: update for cron job

README.md

@@ -1,20 +1,17 @@
 # KV Enqueue Example
 
 This project is in support of a
-[request for feedback](https://discord.com/channels/684898665143206084/1149351471851257986/1149355026158977048)
-on the new Deno KV queue APIs.
+[request for feedback](https://discord.com/channels/684898665143206084/1174052112536195102/1174056992470474803)
+on the new Deno cron API.  It has been reworked from a previous RFC for KV queues
 
 Associated web application: https://kv-enqueue-example.deno.dev/
 
 ## Overview
 
 This project is a [Fresh](https://fresh.deno.dev/) application. On server startup it
-sets up an enqueued message to fetch the last hour's particulate air pollution
+registers an hourly cron job to fetch the last hour's particulate air pollution
 levels (pm2.5 and pm10) in London. This data is added to previously retrieved
-data and the last 7 days worth is retained. Once the last hour's data is
-retrieved, it schedules another job for an hour later to do the same again,
-creating an hourly recurring job.  As per the API, an isolate will be spun up on Deploy
-if none are running to handle the job execution.
+data and the last 7 days worth is retained. 
 
 All logic around the new queue APIs can be found in the [main.ts](https://github.com/cknight/kv_enqueue_test/blob/main/main.ts) file.
 
@@ -30,42 +27,3 @@ In addition to collecting the data, it is also charted on Deploy along with
 stats around the accuracy of the last message delivered and when the next
 message is due to be delivered. You can see this by visiting: https://kv-enqueue-example.deno.dev/
 
-## KV Queue Feedback
-
-This was an interesting exercise to work with the new queue API. Here are some
-thoughts:
-
-- **No ability to see what's queued** - During development I often accidentally
-  queued multiple repeating jobs when I only ever want a single one, but it's
-  hard to know when I've done this.
-- **No queue management** - I can't clear the queue or delete individual queued
-  items from it. A 'shadow' queue could be used by keeping track of items on KV
-  and handling management through that (e.g. ignoring messages delivered in
-  `listenQueue` if they are missing from the 'shadow' queue), but this seems
-  clunky (and prone to mistake) when KV must already have this info.
-- **Recurring queue setup is fiddly and potentially brittle** - For example, if
-  the external API I'm calling within `listenQueue` is down, and KV exhausts
-  retry attempts to deliver the message, the job will not be rescheduled as my
-  code schedules the next one only after successful processing of a message. A
-  recurring job API would be nice and abstract the complexity away from the
-  user.
-- **Docs need significant improvements** - While the basic functionality is well
-  described, there's a lot of nuance missing. Documentation on basic usage
-  patterns would be good too as would a thorough description of message
-  delivery, how and when retries happen, max number of retries, retries backoff
-  (if that exists), etc.
-- **Concerns around server downtime** - If your server isn't running when a
-  message is due to be delivered, the message is delivered the next time it is
-  up and running with your `listenQueue` registered. I can imagine a scenario
-  where you have many missed messages and they flood the `listenQueue`
-  implementation all at once. If Deploy were down for a period, this could
-  impact bringing Deploy back up and online for example, or flood services in
-  use by the message deliveries.
-- **Strong primitives** - Despite some challenges and concerns detailed above,
-  on the positive side I'm really impressed with the primitives I have to work
-  with. Combining queue's with KV atomic operations gives a strong foundation
-  for a serverless environment. Atomic operations really open up a lot of
-  possibilities for safe execution of code.
-- **Simple API** - Though the recurring job was challenging to setup in a robust
-  manner, the `enqueue` and `listenQueue` APIs were simple and straightforward.
-  So far they seem to do what is advertised on the tin.