From 9ca7444e5e7de023b8e9acd3d54429b472cb9f49 Mon Sep 17 00:00:00 2001
From: Menghan Li <menghanl@google.com>
Date: Wed, 3 Apr 2019 17:46:57 -0700
Subject: [PATCH 1/2] addrConn: not reset backoff if update address in
 TransientFailure

---
 clientconn.go | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/clientconn.go b/clientconn.go
index 8255caef929b..b5e69c75c54e 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -758,7 +758,6 @@ func (ac *addrConn) connect() error {
 		ac.mu.Unlock()
 		return nil
 	}
-	ac.updateConnectivityState(connectivity.Connecting)
 	ac.mu.Unlock()
 
 	// Start a goroutine connecting to the server asynchronously.
@@ -768,7 +767,16 @@ func (ac *addrConn) connect() error {
 
 // tryUpdateAddrs tries to update ac.addrs with the new addresses list.
 //
-// It checks whether current connected address of ac is in the new addrs list.
+// If ac is Connecting, it returnes false. The caller should tear down the ac
+// and create a new one. Note that the backoff will be reset when this happens.
+//
+// If ac is TransientFailure, it updates ac.addrs and returns true. The updated
+// addresses will be picked up by retry in the next iteration after backoff.
+//
+// If ac is Shutdown or Idle, it updates ac.addrs and returns true.
+//
+// If ac is Ready, it checks whether current connected address of ac is in the
+// new addrs list.
 //  - If true, it updates ac.addrs and returns true. The ac will keep using
 //    the existing connection.
 //  - If false, it does nothing and returns false.
@@ -776,17 +784,18 @@ func (ac *addrConn) tryUpdateAddrs(addrs []resolver.Address) bool {
 	ac.mu.Lock()
 	defer ac.mu.Unlock()
 	grpclog.Infof("addrConn: tryUpdateAddrs curAddr: %v, addrs: %v", ac.curAddr, addrs)
-	if ac.state == connectivity.Shutdown {
+	if ac.state == connectivity.Shutdown ||
+		ac.state == connectivity.TransientFailure ||
+		ac.state == connectivity.Idle {
 		ac.addrs = addrs
 		return true
 	}
 
-	// Unless we're busy reconnecting already, let's reconnect from the top of
-	// the list.
-	if ac.state != connectivity.Ready {
+	if ac.state == connectivity.Connecting {
 		return false
 	}
 
+	// ac.state is Ready, try to find the connected address.
 	var curAddrFound bool
 	for _, a := range addrs {
 		if reflect.DeepEqual(ac.curAddr, a) {
@@ -1035,6 +1044,9 @@ func (ac *addrConn) resetTransport() {
 		// The spec doesn't mention what should be done for multiple addresses.
 		// https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md#proposed-backoff-algorithm
 		connectDeadline := time.Now().Add(dialDuration)
+
+		ac.updateConnectivityState(connectivity.Connecting)
+		ac.transport = nil
 		ac.mu.Unlock()
 
 		newTr, addr, reconnect, err := ac.tryAllAddrs(addrs, connectDeadline)
@@ -1131,8 +1143,6 @@ func (ac *addrConn) tryAllAddrs(addrs []resolver.Address, connectDeadline time.T
 			ac.mu.Unlock()
 			return nil, resolver.Address{}, nil, errConnClosing
 		}
-		ac.updateConnectivityState(connectivity.Connecting)
-		ac.transport = nil
 
 		ac.cc.mu.RLock()
 		ac.dopts.copts.KeepaliveParams = ac.cc.mkp

From 96dc2629b0d2b3400779198344c83f3002c7ea2d Mon Sep 17 00:00:00 2001
From: Menghan Li <menghanl@google.com>
Date: Wed, 29 May 2019 16:09:54 -0700
Subject: [PATCH 2/2] -s

---
 clientconn.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/clientconn.go b/clientconn.go
index b5e69c75c54e..880f2e499ccd 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -767,8 +767,8 @@ func (ac *addrConn) connect() error {
 
 // tryUpdateAddrs tries to update ac.addrs with the new addresses list.
 //
-// If ac is Connecting, it returnes false. The caller should tear down the ac
-// and create a new one. Note that the backoff will be reset when this happens.
+// If ac is Connecting, it returns false. The caller should tear down the ac and
+// create a new one. Note that the backoff will be reset when this happens.
 //
 // If ac is TransientFailure, it updates ac.addrs and returns true. The updated
 // addresses will be picked up by retry in the next iteration after backoff.