Frontend Asset Optimization#8
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WalkthroughA read-write mutex was introduced to synchronize concurrent access to the global Changes
Estimated code review effort🎯 2 (Simple) | ⏱️ ~7 minutes Poem
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Actionable comments posted: 1
📜 Review details
Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro
📒 Files selected for processing (1)
pkg/api/webassets/webassets.go(2 hunks)
🔇 Additional comments (3)
pkg/api/webassets/webassets.go (3)
11-11: LGTM! Import addition is necessary and correctly placed.The sync package import is required for the RWMutex functionality and follows Go import conventions.
35-38: Well-structured synchronization with clear intent.The reorganization into a var block with descriptive comments is excellent. The mutex naming follows Go conventions, and the TODO comment shows good architectural awareness about eliminating global state.
69-70: Cache update logic is correct.The cache is properly updated while holding the write lock, and returning the cached result is appropriate.
| entryPointAssetsCacheMu.RLock() | ||
| ret := entryPointAssetsCache | ||
| entryPointAssetsCacheMu.RUnlock() | ||
|
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||
| if cfg.Env != setting.Dev && ret != nil { | ||
| return ret, nil | ||
| } | ||
| entryPointAssetsCacheMu.Lock() | ||
| defer entryPointAssetsCacheMu.Unlock() |
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Fix race condition in double-checked locking pattern.
The current implementation has a race condition between releasing the read lock (line 43) and acquiring the write lock (line 48). Multiple goroutines could unnecessarily recompute the cache.
Apply this diff to implement proper double-checked locking:
- entryPointAssetsCacheMu.RLock()
- ret := entryPointAssetsCache
- entryPointAssetsCacheMu.RUnlock()
-
- if cfg.Env != setting.Dev && ret != nil {
- return ret, nil
- }
- entryPointAssetsCacheMu.Lock()
- defer entryPointAssetsCacheMu.Unlock()
+ // Fast path: check cache with read lock
+ entryPointAssetsCacheMu.RLock()
+ if cfg.Env != setting.Dev && entryPointAssetsCache != nil {
+ ret := entryPointAssetsCache
+ entryPointAssetsCacheMu.RUnlock()
+ return ret, nil
+ }
+ entryPointAssetsCacheMu.RUnlock()
+
+ // Slow path: update cache with write lock
+ entryPointAssetsCacheMu.Lock()
+ defer entryPointAssetsCacheMu.Unlock()
+
+ // Double-check: another goroutine might have populated cache
+ if cfg.Env != setting.Dev && entryPointAssetsCache != nil {
+ return entryPointAssetsCache, nil
+ }📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| entryPointAssetsCacheMu.RLock() | |
| ret := entryPointAssetsCache | |
| entryPointAssetsCacheMu.RUnlock() | |
| if cfg.Env != setting.Dev && ret != nil { | |
| return ret, nil | |
| } | |
| entryPointAssetsCacheMu.Lock() | |
| defer entryPointAssetsCacheMu.Unlock() | |
| // Fast path: check cache with read lock | |
| entryPointAssetsCacheMu.RLock() | |
| if cfg.Env != setting.Dev && entryPointAssetsCache != nil { | |
| ret := entryPointAssetsCache | |
| entryPointAssetsCacheMu.RUnlock() | |
| return ret, nil | |
| } | |
| entryPointAssetsCacheMu.RUnlock() | |
| // Slow path: update cache with write lock | |
| entryPointAssetsCacheMu.Lock() | |
| defer entryPointAssetsCacheMu.Unlock() | |
| // Double-check: another goroutine might have populated cache | |
| if cfg.Env != setting.Dev && entryPointAssetsCache != nil { | |
| return entryPointAssetsCache, nil | |
| } |
🤖 Prompt for AI Agents
In pkg/api/webassets/webassets.go around lines 41 to 49, the current
double-checked locking pattern releases the read lock before acquiring the write
lock, causing a race condition where multiple goroutines may recompute the
cache. To fix this, after acquiring the write lock, re-check if the cache is
still nil before recomputing it. This ensures only one goroutine updates the
cache while others use the cached value.
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This pull request has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in 2 weeks if no further activity occurs. Please feel free to give a status update or ping for review. Thank you for your contributions! |
|
This pull request has been automatically closed because it has not had any further activity in the last 2 weeks. Thank you for your contributions! |
2 participants
Test 8
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