💻 [API] Enable response caching for mocks

[neel1996]

Summary

Explore springboot caching to enable it for mock responses. Use the hash generated from the request body + headers as the key for the cache

Scope of the issue

To improve mock response performance

Impacted area

• [ ] UI
• [X] Backend

Supporting artifacts

No response

[neel1996]

Caching & Eviction considerations

Caching

• The mock response for existing mocks will be cached whenever a mock endpoint is invoked by a client. A unique hash will be generated using the following parameters to be used as the cache key

Route + Http method + Query param string + Request headers + Request body

• When a new mock gets created, the same unique parameters mentioned above will be used to generate an unique hash for the key

Eviction

• The cache will be evicted based on sliding expiry policy. The cache that has not been accessed for the past 60 minutes will be evicted
• ** The entire cache will be evicted when a mock is updated or archived. The thought process behind this decision is that when the user updates an existing mock, then evicting the unique mock will not be possible if a client has already triggered the caching with a different set of request headers. This will lead to inconsistencies if we try to evict a cache based on the unique key generated from the mock fetched from the Database

E.g:

Let's assume "client-x" invokes a "mock_a" with the following request headers 

- Authorization
- Content-type
- Host

These headers will decide the cache key. However, it is not necessary for the mock stored in the DB to have the same set of headers if strict header matching is not enabled for the mock.

In this case, if the user updates "mock_a", then the eviction will not remove the mock data from the cache as the hashed key will be different. Hence, all the existing cache needs to be evicted to ensure consistency