redis: Configurable Username

The Redis ACL system was introduced with Redis 6.0. It introduced users
with precisely granular permissions. This change allows Icinga DB to
connect to a Redis with an ACL user.

redis/client.go

@@ -52,6 +52,7 @@ func NewClientFromConfig(c *Config, logger *logging.Logger) (*Client, error) {
 
 	options := &redis.Options{
 		Dialer:      dialWithLogging(dialer, logger),
+		Username:    c.Username,
 		Password:    c.Password,
 		DB:          0, // Use default DB,
 		ReadTimeout: c.Options.Timeout,

redis/config.go

@@ -44,6 +44,7 @@ func (o *Options) Validate() error {
 type Config struct {
 	Host       string     `yaml:"host"`
 	Port       int        `yaml:"port"`
+	Username   string     `yaml:"username"`
 	Password   string     `yaml:"password"`
 	TlsOptions config.TLS `yaml:",inline"`
 	Options    Options    `yaml:"options"`
@@ -55,5 +56,9 @@ func (r *Config) Validate() error {
 		return errors.New("Redis host missing")
 	}
 
+	if r.Username != "" && r.Password == "" {
+		return errors.New("A Redis username requires a password as well")
+	}
+
 	return r.Options.Validate()
 }