Merge pull request #11 from daxmc99/fix_scale_0

Drop retry logic from autoscaler

pkg/gatewayserver/roundtripper.go

@@ -17,15 +17,8 @@ import (
 	"crypto/tls"
 	"net"
 	"net/http"
-	"strconv"
 
-	"github.com/sirupsen/logrus"
 	"golang.org/x/net/http2"
-	"k8s.io/apimachinery/pkg/util/wait"
-)
-
-const (
-	requestCountHTTPHeader = "Request-Retry-Count"
 )
 
 type roundTripperFunc func(*http.Request) (*http.Response, error)
@@ -55,71 +48,3 @@ var http2Transport http.RoundTripper = &http2.Transport{
 
 // AutoTransport uses h2c for HTTP2 requests and falls back to `http.DefaultTransport` for all others
 var autoTransport = newHTTPTransport(http.DefaultTransport, http2Transport)
-
-type retryCond func(*http.Response) bool
-
-// RetryStatus will filter responses matching `status`
-func retryStatus(status int) retryCond {
-	return func(resp *http.Response) bool {
-		return resp.StatusCode == status
-	}
-}
-
-type retryRoundTripper struct {
-	transport       http.RoundTripper
-	backoffSettings wait.Backoff
-	retryConditions []retryCond
-}
-
-// RetryRoundTripper retries a request on error or retry condition, using the given `retry` strategy
-func newRetryRoundTripper(rt http.RoundTripper, b wait.Backoff, conditions ...retryCond) http.RoundTripper {
-	return &retryRoundTripper{
-		transport:       rt,
-		backoffSettings: b,
-		retryConditions: conditions,
-	}
-}
-
-func (rrt *retryRoundTripper) RoundTrip(r *http.Request) (resp *http.Response, err error) {
-	// The request body cannot be read multiple times for retries.
-	// The workaround is to clone the request body into a byte reader
-	// so the body can be read multiple times.
-	if r.Body != nil {
-		logrus.Debugf("Wrapping body in a rewinder.")
-		r.Body = newRewinder(r.Body)
-	}
-
-	attempts := 0
-	wait.ExponentialBackoff(rrt.backoffSettings, func() (bool, error) {
-		attempts++
-		r.Header.Add(requestCountHTTPHeader, strconv.Itoa(attempts))
-		resp, err = rrt.transport.RoundTrip(r)
-
-		if err != nil {
-			logrus.Errorf("Error making a request: %s", err)
-			return false, nil
-		}
-
-		for _, retryCond := range rrt.retryConditions {
-			if retryCond(resp) {
-				resp.Body.Close()
-				return false, nil
-			}
-		}
-		return true, nil
-	})
-
-	if err == nil {
-		logrus.Infof("Finished after %d attempt(s). Response code: %d", attempts, resp.StatusCode)
-
-		if resp.Header == nil {
-			resp.Header = make(http.Header)
-		}
-
-		resp.Header.Add(requestCountHTTPHeader, strconv.Itoa(attempts))
-	} else {
-		logrus.Errorf("Failed after %d attempts. Last error: %v", attempts, err)
-	}
-
-	return
-}

pkg/gatewayserver/serve.go

@@ -18,15 +18,11 @@ import (
 	"github.com/sirupsen/logrus"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/proxy"
-	"k8s.io/apimachinery/pkg/util/wait"
 )
 
 const (
-	maxRetries             = 18 // the sum of all retries would add up to 1 minute
-	minRetryInterval       = 100 * time.Millisecond
-	exponentialBackoffBase = 1.3
-	RioNameHeader          = "X-Rio-ServiceName"
-	RioNamespaceHeader     = "X-Rio-Namespace"
+	RioNameHeader      = "X-Rio-ServiceName"
+	RioNamespaceHeader = "X-Rio-Namespace"
 )
 
 func NewHandler(rContext *types.Context, lock *sync.RWMutex, autoscalers map[string]*servicescale.SimpleScale) Handler {
@@ -81,8 +77,7 @@ func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	app, version := services.AppAndVersion(svc)
 	serveFQDN(name2.SafeConcatName(app, version), namespace, checkPort, w, r)
 
-	logrus.Infof("activating service %s/%s takes %v seconds", svc.Name, svc.Namespace, time.Now().Sub(start).Seconds())
-	return
+	logrus.Infof("activating service %s/%s takes %v seconds", svc.Name, svc.Namespace, time.Since(start).Seconds())
 }
 
 func serveFQDN(name, namespace, port string, w http.ResponseWriter, r *http.Request) {
@@ -95,15 +90,7 @@ func serveFQDN(name, namespace, port string, w http.ResponseWriter, r *http.Requ
 	r.URL.Host = targetURL.Host
 	r.Host = targetURL.Host
 
-	shouldRetry := []retryCond{retryStatus(http.StatusServiceUnavailable), retryStatus(http.StatusBadGateway)}
-	backoffSettings := wait.Backoff{
-		Duration: minRetryInterval,
-		Factor:   exponentialBackoffBase,
-		Steps:    maxRetries,
-	}
-
-	rt := newRetryRoundTripper(autoTransport, backoffSettings, shouldRetry...)
-	httpProxy := proxy.NewUpgradeAwareHandler(targetURL, rt, true, false, er)
+	httpProxy := proxy.NewUpgradeAwareHandler(targetURL, autoTransport, true, false, er)
 	httpProxy.ServeHTTP(w, r)
 }