Clear throttle cache on ConsumerThrottleLimit.save

[mbertrand]

What are the relevant tickets?

Closes https://github.com/mitodl/hq/issues/7107

Description (What does it do?)

Overrides the ConsumerThrottleLimit.save function to clear the throttle cache.

Screenshots (if appropriate):

• Desktop screenshots
• Mobile width screenshots

How can this be tested?

• Change the existing ConsumerThrottleLimit with key recommendation_bot to 1/hour for auth and anon users at http://ai.open.odl.local:8002/admin/main/consumerthrottlelimit/
• Try to make more 2+ requests in short order from the home page. After the 1st you should get a message like "Please try again in 59m"
• Go back to http://ai.open.odl.local:8002/admin/main/consumerthrottlelimit/ and change the interval to "minute"
• Try to make more requests, you should get a message like "Please try again in 52s"

[gemini-code-assist]

Hello @mbertrand, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

Summary of Changes

This pull request addresses issue #7107 by modifying the ConsumerThrottleLimit model to clear the throttle cache whenever an instance of the model is saved. This ensures that changes to throttle limits are immediately reflected in the application's behavior. The changes involve overriding the save method of the ConsumerThrottleLimit model to delete the CONSUMER_THROTTLES_KEY from the cache. Additionally, a test case has been added to verify that the cache is indeed cleared when the model is saved.

Highlights

• Cache Invalidation: The primary goal is to invalidate the consumer throttles cache whenever a ConsumerThrottleLimit model is saved, ensuring that the most up-to-date throttle configurations are used.
• Model Override: The save method of the ConsumerThrottleLimit model is overridden to include cache invalidation logic.
• Test Coverage: A new test case is added to verify that saving a ConsumerThrottleLimit model clears the cache as expected.

Changelog

Click here to see the changelog

• main/constants.py
  • Added CONSUMER_THROTTLES_KEY constant to store the key used for caching consumer throttles. This constant is used to invalidate the cache when throttle limits are updated. (line 16)
• main/consumer_throttles.py
  • Imported CONSUMER_THROTTLES_KEY from main.constants to be used for cache invalidation. (line 15)
  • Removed the duplicate definition of CONSUMER_THROTTLES_KEY as it is now defined in main/constants.py. (line 21)
• main/models.py
  • Imported cache from django.core.cache to allow cache operations within the model. (line 5)
  • Imported CONSUMER_THROTTLES_KEY from main.constants to be used for cache invalidation. (line 9)
  • Overrode the save method to delete the CONSUMER_THROTTLES_KEY from the cache before saving the model. (lines 83-86)
• main/models_test.py
  • Added a new test case test_throttle_limit_save_reset_cache to verify that saving a ConsumerThrottleLimit model clears the cache. (lines 10-39)

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---

A cache we keep with care,
Throttle limits stored with flair,
But when they change,
A quick arrange,
To clear the cache, beyond compare.

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[gemini-code-assist]

Code Review

This pull request introduces a mechanism to clear the throttle cache whenever a ConsumerThrottleLimit object is saved. This ensures that changes to throttle limits are reflected immediately, which is great. The implementation includes a test case to verify this behavior. Overall, the changes look good, but I have a few suggestions.

Summary of Findings

• Cache invalidation on save: The save method of the ConsumerThrottleLimit model is overridden to delete the CONSUMER_THROTTLES_KEY from the cache, ensuring that throttle limits are refreshed when the model is updated.
• Test case for cache invalidation: A test case test_throttle_limit_save_reset_cache is added to verify that saving changes to the ConsumerThrottleLimit model resets the cache as expected.

Merge Readiness

The code changes seem correct and the included test case provides confidence in the implementation. I recommend merging this pull request after addressing the comments below. I am unable to directly approve the pull request, and users should have others review and approve this code before merging.

[abeglova]

lgtm