Merge 72d872f into 5a67a24

api/v1/lib/httpcli/httpsched/httpsched.go

@@ -37,9 +37,10 @@ type (
 
 	client struct {
 		*httpcli.Client
-		redirect       RedirectSettings
-		allowReconnect bool // feature flag
-		listener       func(Notification)
+		redirect          RedirectSettings
+		allowReconnect    bool // feature flag
+		listener          func(Notification)
+		candidateSelector CandidateSelector
 	}
 
 	// Caller is the public interface a framework scheduler's should consume
@@ -74,6 +75,10 @@ type (
 		requestOpts    []httpcli.RequestOpt // requestOpts are temporary per-request options
 		opt            httpcli.Opt          // opt is a temporary client option
 	}
+
+	// CandidateSelector returns the next endpoint to try if there are errors reaching the mesos master,
+	// or else an empty string if there are no such candidates.
+	CandidateSelector func() string
 )
 
 const (
@@ -134,6 +139,14 @@ func AllowReconnection(v bool) Option {
 	}
 }
 
+func EndpointCandidates(cs CandidateSelector) Option {
+	return func(c *client) Option {
+		old := c.candidateSelector
+		c.candidateSelector = cs
+		return EndpointCandidates(old)
+	}
+}
+
 // NewCaller returns a scheduler API Client in the form of a Caller. Concurrent invocations
 // of Call upon the returned caller are safely executed in a serial fashion. It is expected that
 // there are no other users of the given Client since its state may be modified by this impl.
@@ -173,15 +186,35 @@ func (cli *client) httpDo(ctx context.Context, m encoding.Marshaler, opt ...http
 	opt = append(opt, httpcli.Context(ctx))
 	for attempt := 0; ; attempt++ {
 		resp, err = cli.Client.Do(m, opt...)
-		redirectErr, ok := err.(*mesosRedirectionError)
-		if !ok {
-			return resp, err
+		if err == nil {
+			return
 		}
+		redirectErr, ok := err.(*mesosRedirectionError)
+
 		if attempt < cli.redirect.MaxAttempts {
+			var candidate string
+			if !ok {
+				if cli.candidateSelector == nil {
+					if debug {
+						log.Printf("not found candidate selector, using url when initilize framework")
+					}
+					candidate = cli.Endpoint()
+				} else {
+					candidate = cli.candidateSelector()
+				}
+				if candidate == "" {
+					if debug {
+						log.Printf("not found candidate url, return directly")
+					}
+					return
+				}
+			} else {
+				candidate = redirectErr.newURL
+			}
 			if debug {
-				log.Println("redirecting to " + redirectErr.newURL)
+				log.Printf("redirecting to %v", candidate)
 			}
-			cli.With(httpcli.Endpoint(redirectErr.newURL))
+			cli.With(httpcli.Endpoint(candidate))
 			select {
 			case <-getBackoff():
 			case <-ctx.Done():