resty.go

# create a rate limiter to allow the http request at max 1 token within 1 sec
# this is the best way to avoid DDOS on the server because multiple requests
# can happen in different Goroutines
rl := rate.NewLimiter(rate.Every(time.Second), 1)

# We want to set up a common base client to do all the requests
client := resty.New().
	SetTLSClientConfig(&tls.Config{...}).		# setup TLS
	SetTimeout(30 * time.Second).			# client timeout
	SetBaseURL(url).					# base URL for all APIs
	SetHeaders(map[string]string{			# common headers
		"Accept":       "application/json",
		"Content-Type": "application/json",
	}).
	OnBeforeRequest(func(c *resty.Client, req *resty.Request) error {
		# apply the rate limiter before each request
		return rl.Wait(ctx)
	}).
	OnAfterResponse(func(c *resty.Client, resp *resty.Response) error {
		# check error after each request
		if resp.IsError() {
			return fmt.Errorf(
				"status code: %d, response: %s",
				resp.StatusCode(),
				resp.String(),
			)
		}
		return nil
	})

# now we can use this base client in the following way
client.R().
	SetContext(ctx).
	SetBody(...).
	SetResult(...).
	Post(path)