From eb0ae8bcddc1021b815fec10e7b451193c6c4b6d Mon Sep 17 00:00:00 2001
From: Apti Umayev <apti.umayev@evobitsit.com>
Date: Fri, 11 Feb 2022 07:30:11 +0100
Subject: [PATCH] Fix cache mutex lock

---
 middleware/cache/cache.go | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/middleware/cache/cache.go b/middleware/cache/cache.go
index f27b7638ab9..aefe5c12a84 100644
--- a/middleware/cache/cache.go
+++ b/middleware/cache/cache.go
@@ -70,9 +70,8 @@ func New(config ...Config) fiber.Handler {
 		// Get entry from pool
 		e := manager.get(key)
 
-		// Lock entry and unlock when finished
+		// Lock entry
 		mux.Lock()
-		defer mux.Unlock()
 
 		// Get timestamp
 		ts := atomic.LoadUint64(&timestamp)
@@ -105,15 +104,24 @@ func New(config ...Config) fiber.Handler {
 
 			c.Set(cfg.CacheHeader, cacheHit)
 
+			mux.Unlock()
+
 			// Return response
 			return nil
 		}
 
+		// make sure we're not blocking concurrent requests - do unlock
+		mux.Unlock()
+
 		// Continue stack, return err to Fiber if exist
 		if err := c.Next(); err != nil {
 			return err
 		}
 
+		// lock entry back and unlock on finish
+		mux.Lock()
+		defer mux.Unlock()
+
 		// Don't cache response if Next returns true
 		if cfg.Next != nil && cfg.Next(c) {
 			c.Set(cfg.CacheHeader, cacheUnreachable)