feat(verification): back email/reset codes with Redis when available

common/verification.go

@@ -1,10 +1,12 @@
 package common
 
 import (
+	"crypto/subtle"
 	"strings"
 	"sync"
 	"time"
 
+	"github.com/go-redis/redis/v8"
 	"github.com/google/uuid"
 )
 
@@ -18,6 +20,8 @@ const (
 	PasswordResetPurpose     = "r"
 )
 
+const verificationRedisPrefix = "verify_code:"
+
 var verificationMutex sync.Mutex
 var verificationMap map[string]verificationValue
 var verificationMapMaxSize = 10
@@ -32,7 +36,18 @@ func GenerateVerificationCode(length int) string {
 	return code[:length]
 }
 
+func verificationRedisKey(key, purpose string) string {
+	return verificationRedisPrefix + purpose + ":" + key
+}
+
 func RegisterVerificationCodeWithKey(key string, code string, purpose string) {
+	if RedisEnabled {
+		ttl := time.Duration(VerificationValidMinutes) * time.Minute
+		if err := RedisSet(verificationRedisKey(key, purpose), code, ttl); err != nil {
+			SysError("RegisterVerificationCodeWithKey: redis set failed: " + err.Error())
+		}
+		return
+	}
 	verificationMutex.Lock()
 	defer verificationMutex.Unlock()
 	verificationMap[purpose+key] = verificationValue{
@@ -45,6 +60,16 @@ func RegisterVerificationCodeWithKey(key string, code string, purpose string) {
 }
 
 func VerifyCodeWithKey(key string, code string, purpose string) bool {
+	if RedisEnabled {
+		stored, err := RedisGet(verificationRedisKey(key, purpose))
+		if err != nil {
+			if err != redis.Nil {
+				SysError("VerifyCodeWithKey: redis get failed: " + err.Error())
+			}
+			return false
+		}
+		return subtle.ConstantTimeCompare([]byte(stored), []byte(code)) == 1
+	}
 	verificationMutex.Lock()
 	defer verificationMutex.Unlock()
 	value, okay := verificationMap[purpose+key]
@@ -56,6 +81,12 @@ func VerifyCodeWithKey(key string, code string, purpose string) bool {
 }
 
 func DeleteKey(key string, purpose string) {
+	if RedisEnabled {
+		if err := RedisDelKey(verificationRedisKey(key, purpose)); err != nil {
+			SysError("DeleteKey: redis del failed: " + err.Error())
+		}
+		return
+	}
 	verificationMutex.Lock()
 	defer verificationMutex.Unlock()
 	delete(verificationMap, purpose+key)

common/verification_test.go

@@ -0,0 +1,38 @@
+package common
+
+import "testing"
+
+// Exercise the in-process map fallback path that's used when Redis is
+// disabled. The Redis path is covered by live testing.
+func TestVerifyCodeWithKey_MemoryFallback(t *testing.T) {
+	prevRedis := RedisEnabled
+	RedisEnabled = false
+	t.Cleanup(func() { RedisEnabled = prevRedis })
+
+	const key = "user@example.com"
+	const code = "abc123"
+
+	if VerifyCodeWithKey(key, code, EmailVerificationPurpose) {
+		t.Fatalf("expected false before code is registered")
+	}
+
+	RegisterVerificationCodeWithKey(key, code, EmailVerificationPurpose)
+
+	if !VerifyCodeWithKey(key, code, EmailVerificationPurpose) {
+		t.Fatalf("expected true after registration")
+	}
+
+	if VerifyCodeWithKey(key, "wrong", EmailVerificationPurpose) {
+		t.Fatalf("expected false for wrong code")
+	}
+
+	// Different purpose namespace must not collide.
+	if VerifyCodeWithKey(key, code, PasswordResetPurpose) {
+		t.Fatalf("purposes must be isolated")
+	}
+
+	DeleteKey(key, EmailVerificationPurpose)
+	if VerifyCodeWithKey(key, code, EmailVerificationPurpose) {
+		t.Fatalf("expected false after DeleteKey")
+	}
+}