App should be aware of it's discount status being updated from Discounts page

[cyberabis]

A custom discount created by an app can be activated / deactivated / deleted from the Shopify's discount page. App has to keep (long) polling to be aware of this change.

Why this is a problem?
For example, an app like volume discount typically displays a widget on the product page. The product page is heavily accessed and its not ideal to query the GraphQL for each product page visit to find applicable volume discounts. This also slows down the widget load on page. So the app should be able to cache the discounts it created. And if the app caches the discount, any update on the discount should be notified to the app.

Suggested proposals I can think of:
Option 1: Do not allow to activate / deactivate / delete custom discounts from the Discount page. This has to be managed through the app, or an app API.
Option 2: Add a webhook topic that app can subscribe and listen to. Will be even better if only the app's related discount changes are notified.

Related discussion on Slack:
https://shopifypartners.slack.com/archives/C0225DTE1M1/p1680176461557429
https://shopifypartners.slack.com/archives/C0225DTE1M1/p1676592256778369

[rahultiwari-hulkapps]

+1
I believe we must have a webhook for this so the app can be aware that its discount is deleted/disabled from the Shopify admin discount page.

[ayushishah169]

+1

[haripraneshHP]

+1

[nickwesselman]

There are now webhook topics for discounts.

https://shopify.dev/docs/api/admin-graphql/2024-01/enums/WebhookSubscriptionTopic#value-discountscreate