[API Policies] Semantic Cache Policy Issue

[DakshithaS]

Overview

Cache isolation bug prevents cache hits when API identity information is missing, completely defeating the caching mechanism.

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Issue Details

Fallback to RequestID Causes Cache Isolation Per Request

File: semanticcache.go (lines 429-434)

Description:
When apiID is ":" (indicating missing API name/version), the code falls back to using ctx.RequestID as the cache key. Since RequestID is unique per request, this prevents any cache sharing across requests - each response gets cached under a different key and can never be retrieved.

Code Flow:

apiID := fmt.Sprintf("%s:%s", ctx.APIName, ctx.APIVersion)
if apiID == ":" {
    apiID = ctx.RequestID // PROBLEM: Unique per request!
}

Proposed Fix:
Use a meaningful fallback for apiID instead of RequestID, such as a default value or log a warning about missing apiID.

Impact:
Cache hits will never occur when apiID is ":", completely defeating the purpose of semantic caching.

Reference

• Consolidate APIM policies into gateway-controllers repository gateway-controllers#1