Function executeWithRetry

proxy.go:194–278

(
	ctx context.Context,
	s *scope,
	maxRetry int,
	rp func(http.ResponseWriter, *http.Request),
	rw ResponseWriterWithCode,
	srw StatResponseWriter,
	req *http.Request,
	monitorDuration func(float64),
	monitorRetryRequestInc func(prometheus.Labels),
)

}

func executeWithRetry(
	ctx context.Context,
	s *scope,
	maxRetry int,
	rp func(http.ResponseWriter, *http.Request),
	rw ResponseWriterWithCode,
	srw StatResponseWriter,
	req *http.Request,
	monitorDuration func(float64),
	monitorRetryRequestInc func(prometheus.Labels),
) (float64, error) {
	startTime := time.Now()
	var since float64

	var body []byte
	var err error
	// Use readAndRestoreRequestBody to read the entire request body into a byte slice,
	// and to restore req.Body so that it can be reused later in the code.
	if maxRetry > 0 {
		body, err = readAndRestoreRequestBody(req)
		if err != nil {
			since := time.Since(startTime).Seconds()
			return since, err
		}
	}

	numRetry := 0
	for {
		rp(rw, req)

		err := ctx.Err()
		if err != nil {
			since = time.Since(startTime).Seconds()

			return since, err
		}
		// The request has been successfully proxied.

		srw.SetStatusCode(rw.StatusCode())
		// StatusBadGateway response is returned by http.ReverseProxy when
		// it cannot establish connection to remote host.
		if rw.StatusCode() == http.StatusBadGateway {
			log.Debugf("the invalid host is: %s", s.host)
			s.host.Penalize()
			// comment s.host.dec() line to avoid double increment; issue #322
			// s.host.dec()
			s.host.SetIsActive(false)
			nextHost := s.cluster.getHost()
			// The query could be retried if it has no stickiness to a certain server
			if numRetry < maxRetry && nextHost.IsActive() && s.sessionId == "" {
				// the query execution has been failed
				monitorRetryRequestInc(s.labels)
				currentHost := s.host

				// decrement the current failed host counter and increment the new host
				// as for the end of the requests we will close the scope and in that closed scope
				// decrement the new host PR - https://github.com/ContentSquare/chproxy/pull/357
				if currentHost != nextHost {