Method CAS

kv/consul/client.go:130–134

CAS atomically modifies a value in a callback. If value doesn't exist you'll get nil as an argument to your callback.

(ctx context.Context, key string, f func(in interface{}) (out interface{}, retry bool, err error))

// CAS atomically modifies a value in a callback.
// If value doesn't exist you'll get nil as an argument to your callback.
func (c *Client) CAS(ctx context.Context, key string, f func(in interface{}) (out interface{}, retry bool, err error)) error {
	return instrument.CollectedRequest(ctx, "CAS loop", c.consulMetrics.consulRequestDuration, instrument.ErrorCode, func(ctx context.Context) error {
		return c.cas(ctx, key, f)
	})
}

func (c *Client) cas(ctx context.Context, key string, f func(in interface{}) (out interface{}, retry bool, err error)) error {
	retries := c.cfg.MaxCasRetries