From 760fb8b09105859010be6a9c48460ca47beab899 Mon Sep 17 00:00:00 2001
From: Vojtech Vitek <vojtech.vitek@golang.cz>
Date: Wed, 7 Aug 2024 16:13:20 +0200
Subject: [PATCH] Fallback on all Redis errors

---
 httprateredis.go | 39 ++++++++++++++++-----------------------
 1 file changed, 16 insertions(+), 23 deletions(-)

diff --git a/httprateredis.go b/httprateredis.go
index a9ca6f0..ebf321d 100644
--- a/httprateredis.go
+++ b/httprateredis.go
@@ -2,9 +2,7 @@ package httprateredis
 
 import (
 	"context"
-	"errors"
 	"fmt"
-	"net"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -107,13 +105,8 @@ func (c *redisCounter) IncrementBy(key string, currentWindow time.Time, amount i
 			return c.fallbackCounter.IncrementBy(key, currentWindow, amount)
 		}
 		defer func() {
-			if err != nil {
-				// On redis network error, fallback to local in-memory counter.
-				var netErr net.Error
-				if errors.As(err, &netErr) || errors.Is(err, redis.ErrClosed) {
-					c.fallback()
-					err = c.fallbackCounter.IncrementBy(key, currentWindow, amount)
-				}
+			if c.shouldFallback(err) {
+				err = c.fallbackCounter.IncrementBy(key, currentWindow, amount)
 			}
 		}()
 	}
@@ -147,13 +140,8 @@ func (c *redisCounter) Get(key string, currentWindow, previousWindow time.Time)
 			return c.fallbackCounter.Get(key, currentWindow, previousWindow)
 		}
 		defer func() {
-			if err != nil {
-				// On redis network error, fallback to local in-memory counter.
-				var netErr net.Error
-				if errors.As(err, &netErr) || errors.Is(err, redis.ErrClosed) {
-					c.fallback()
-					curr, prev, err = c.fallbackCounter.Get(key, currentWindow, previousWindow)
-				}
+			if c.shouldFallback(err) {
+				curr, prev, err = c.fallbackCounter.Get(key, currentWindow, previousWindow)
 			}
 		}()
 	}
@@ -189,25 +177,30 @@ func (c *redisCounter) IsFallbackActivated() bool {
 	return c.fallbackActivated.Load()
 }
 
-func (c *redisCounter) fallback() {
-	// Activate the in-memory counter fallback, unless activated by some other goroutine.
-	fallbackAlreadyActivated := c.fallbackActivated.Swap(true)
-	if fallbackAlreadyActivated {
-		return
+func (c *redisCounter) shouldFallback(err error) bool {
+	if err == nil {
+		return false
 	}
 
-	go c.reconnect()
+	// Activate the local in-memory counter fallback, unless activated by some other goroutine.
+	alreadyActivated := c.fallbackActivated.Swap(true)
+	if !alreadyActivated {
+		go c.reconnect()
+	}
+
+	return true
 }
 
 func (c *redisCounter) reconnect() {
 	// Try to re-connect to redis every 200ms.
 	for {
+		time.Sleep(200 * time.Millisecond)
+
 		err := c.client.Ping(context.Background()).Err()
 		if err == nil {
 			c.fallbackActivated.Store(false)
 			return
 		}
-		time.Sleep(200 * time.Millisecond)
 	}
 }