make downErr for Balancer down closure

balancer.go

@@ -34,6 +34,7 @@
 package grpc
 
 import (
+	"fmt"
 	"sync"
 
 	"golang.org/x/net/context"
@@ -103,6 +104,26 @@ type Balancer interface {
 	Close() error
 }
 
+// downErr implements net.Error. It is contructed by gRPC internals and passed to the down
+// call of Balancer.
+type downErr struct {
+	timeout   bool
+	temporary bool
+	desc      string
+}
+
+func (e downErr) Error() string   { return e.desc }
+func (e downErr) Timeout() bool   { return e.timeout }
+func (e downErr) Temporary() bool { return e.temporary }
+
+func downErrorf(timeout, temporary bool, format string, a ...interface{}) downErr {
+	return downErr{
+		timeout:   timeout,
+		temporary: temporary,
+		desc:      fmt.Sprintf(format, a...),
+	}
+}
+
 // RoundRobin returns a Balancer that selects addresses round-robin. It starts to watch
 // the name resolution updates.
 func RoundRobin(r naming.Resolver) Balancer {

call.go

@@ -154,7 +154,7 @@ func Invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 		if err != nil {
 			// TODO(zhaoq): Probably revisit the error handling.
 			if err == ErrClientConnClosing {
-				return toRPCErr(err)
+				return Errorf(codes.FailedPrecondition, "%v", err)
 			}
 			if _, ok := err.(transport.StreamError); ok {
 				return toRPCErr(err)
@@ -189,6 +189,7 @@ func Invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 		if err != nil {
 			if put != nil {
 				put()
+				put = nil
 			}
 			if _, ok := err.(transport.ConnectionError); ok {
 				if c.failFast {

clientconn.go

@@ -51,26 +51,27 @@ import (
 )
 
 var (
-	// ErrNoTransportSecurity indicates that there is no transport security
+	// ErrClientConnClosing indicates that the operation is illegal because
+	// the ClientConn is closing.
+	ErrClientConnClosing = errors.New("grpc: the client connection is closing")
+
+	// errNoTransportSecurity indicates that there is no transport security
 	// being set for ClientConn. Users should either set one or explicitly
 	// call WithInsecure DialOption to disable security.
-	ErrNoTransportSecurity = errors.New("grpc: no transport security set (use grpc.WithInsecure() explicitly or set credentials)")
-	// ErrCredentialsMisuse indicates that users want to transmit security information
+	errNoTransportSecurity = errors.New("grpc: no transport security set (use grpc.WithInsecure() explicitly or set credentials)")
+	// errCredentialsMisuse indicates that users want to transmit security information
 	// (e.g., oauth2 token) which requires secure connection on an insecure
 	// connection.
-	ErrCredentialsMisuse = errors.New("grpc: the credentials require transport level security (use grpc.WithTransportAuthenticator() to set)")
-	// ErrClientConnClosing indicates that the operation is illegal because
-	// the ClientConn is closing.
-	ErrClientConnClosing = Errorf(codes.FailedPrecondition, "grpc: the client connection is closing")
-	// ErrClientConnTimeout indicates that the connection could not be
+	errCredentialsMisuse = errors.New("grpc: the credentials require transport level security (use grpc.WithTransportAuthenticator() to set)")
+	// errClientConnTimeout indicates that the connection could not be
 	// established or re-established within the specified timeout.
-	ErrClientConnTimeout = errors.New("grpc: timed out trying to connect")
-	// ErrNetworkIP indicates that the connection is down due to some network I/O error.
-	ErrNetworkIO = errors.New("grpc: failed with network I/O error")
-	// ErrConnDrain indicates that the connection starts to be drained and does not accept any new RPCs.
-	ErrConnDrain = errors.New("grpc: the connection is drained")
-	// ErrConnClosing
-	ErrConnClosing = errors.New("grpc: the addrConn is closing")
+	errClientConnTimeout = errors.New("grpc: timed out trying to connect")
+	// errNetworkIP indicates that the connection is down due to some network I/O error.
+	errNetworkIO = errors.New("grpc: failed with network I/O error")
+	// errConnDrain indicates that the connection starts to be drained and does not accept any new RPCs.
+	errConnDrain = errors.New("grpc: the connection is drained")
+	// errConnClosing indicates that the connection is closing.
+	errConnClosing = errors.New("grpc: the connection is closing")
 	// minimum time to give a connection to complete
 	minConnectTimeout = 20 * time.Second
 )
@@ -337,7 +338,7 @@ func (cc *ClientConn) controller() {
 			}
 		}
 		for _, c := range del {
-			c.tearDown(ErrConnDrain)
+			c.tearDown(errConnDrain)
 		}
 	}
 }
@@ -360,12 +361,12 @@ func (cc *ClientConn) newAddrConn(addr Address, skipWait bool) error {
 			}
 		}
 		if !ok {
-			return ErrNoTransportSecurity
+			return errNoTransportSecurity
 		}
 	} else {
 		for _, cd := range ac.dopts.copts.AuthOptions {
 			if cd.RequireTransportSecurity() {
-				return ErrCredentialsMisuse
+				return errCredentialsMisuse
 			}
 		}
 	}
@@ -529,10 +530,10 @@ func (ac *addrConn) resetTransport(closeTransport bool) error {
 		if ac.state == Shutdown {
 			// ac.tearDown(...) has been invoked.
 			ac.mu.Unlock()
-			return ErrConnClosing
+			return errConnClosing
 		}
 		if ac.down != nil {
-			ac.down(ErrNetworkIO)
+			ac.down(downErrorf(false, true, "%v", errNetworkIO))
 			ac.down = nil
 		}
 		ac.state = Connecting
@@ -545,14 +546,14 @@ func (ac *addrConn) resetTransport(closeTransport bool) error {
 		// Adjust timeout for the current try.
 		copts := ac.dopts.copts
 		if copts.Timeout < 0 {
-			ac.tearDown(ErrClientConnTimeout)
-			return ErrClientConnTimeout
+			ac.tearDown(errClientConnTimeout)
+			return errClientConnTimeout
 		}
 		if copts.Timeout > 0 {
 			copts.Timeout -= time.Since(start)
 			if copts.Timeout <= 0 {
-				ac.tearDown(ErrClientConnTimeout)
-				return ErrClientConnTimeout
+				ac.tearDown(errClientConnTimeout)
+				return errClientConnTimeout
 			}
 		}
 		sleepTime := ac.dopts.bs.backoff(retries)
@@ -570,7 +571,7 @@ func (ac *addrConn) resetTransport(closeTransport bool) error {
 			if ac.state == Shutdown {
 				// ac.tearDown(...) has been invoked.
 				ac.mu.Unlock()
-				return ErrConnClosing
+				return errConnClosing
 			}
 			ac.errorf("transient failure: %v", err)
 			ac.state = TransientFailure
@@ -589,8 +590,8 @@ func (ac *addrConn) resetTransport(closeTransport bool) error {
 				ac.mu.Lock()
 				ac.errorf("connection timeout")
 				ac.mu.Unlock()
-				ac.tearDown(ErrClientConnTimeout)
-				return ErrClientConnTimeout
+				ac.tearDown(errClientConnTimeout)
+				return errClientConnTimeout
 			}
 			closeTransport = false
 			select {
@@ -607,7 +608,7 @@ func (ac *addrConn) resetTransport(closeTransport bool) error {
 			// ac.tearDown(...) has been invoked.
 			ac.mu.Unlock()
 			newTransport.Close()
-			return ErrConnClosing
+			return errConnClosing
 		}
 		ac.state = Ready
 		ac.stateCV.Broadcast()
@@ -662,7 +663,7 @@ func (ac *addrConn) wait(ctx context.Context) (transport.ClientTransport, error)
 		switch {
 		case ac.state == Shutdown:
 			ac.mu.Unlock()
-			return nil, ErrConnClosing
+			return nil, errConnClosing
 		case ac.state == Ready:
 			ct := ac.transport
 			ac.mu.Unlock()
@@ -699,7 +700,7 @@ func (ac *addrConn) tearDown(err error) {
 		ac.cc.mu.Unlock()
 	}()
 	if ac.down != nil {
-		ac.down(err)
+		ac.down(downErrorf(false, false, "%v", err))
 		ac.down = nil
 	}
 	if ac.state == Shutdown {
@@ -716,7 +717,7 @@ func (ac *addrConn) tearDown(err error) {
 		ac.ready = nil
 	}
 	if ac.transport != nil {
-		if err == ErrConnDrain {
+		if err == errConnDrain {
 			ac.transport.GracefulClose()
 		} else {
 			ac.transport.Close()

clientconn_test.go

@@ -47,8 +47,8 @@ func TestDialTimeout(t *testing.T) {
 	if err == nil {
 		conn.Close()
 	}
-	if err != ErrClientConnTimeout {
-		t.Fatalf("Dial(_, _) = %v, %v, want %v", conn, err, ErrClientConnTimeout)
+	if err != errClientConnTimeout {
+		t.Fatalf("Dial(_, _) = %v, %v, want %v", conn, err, errClientConnTimeout)
 	}
 }
 
@@ -61,8 +61,8 @@ func TestTLSDialTimeout(t *testing.T) {
 	if err == nil {
 		conn.Close()
 	}
-	if err != ErrClientConnTimeout {
-		t.Fatalf("grpc.Dial(_, _) = %v, %v, want %v", conn, err, ErrClientConnTimeout)
+	if err != errClientConnTimeout {
+		t.Fatalf("grpc.Dial(_, _) = %v, %v, want %v", conn, err, errClientConnTimeout)
 	}
 }
 
@@ -72,12 +72,12 @@ func TestCredentialsMisuse(t *testing.T) {
 		t.Fatalf("Failed to create credentials %v", err)
 	}
 	// Two conflicting credential configurations
-	if _, err := Dial("Non-Existent.Server:80", WithTransportCredentials(creds), WithTimeout(time.Millisecond), WithBlock(), WithInsecure()); err != ErrCredentialsMisuse {
-		t.Fatalf("Dial(_, _) = _, %v, want _, %v", err, ErrCredentialsMisuse)
+	if _, err := Dial("Non-Existent.Server:80", WithTransportCredentials(creds), WithTimeout(time.Millisecond), WithBlock(), WithInsecure()); err != errCredentialsMisuse {
+		t.Fatalf("Dial(_, _) = _, %v, want _, %v", err, errCredentialsMisuse)
 	}
 	// security info on insecure connection
-	if _, err := Dial("Non-Existent.Server:80", WithPerRPCCredentials(creds), WithTimeout(time.Millisecond), WithBlock(), WithInsecure()); err != ErrCredentialsMisuse {
-		t.Fatalf("Dial(_, _) = _, %v, want _, %v", err, ErrCredentialsMisuse)
+	if _, err := Dial("Non-Existent.Server:80", WithPerRPCCredentials(creds), WithTimeout(time.Millisecond), WithBlock(), WithInsecure()); err != errCredentialsMisuse {
+		t.Fatalf("Dial(_, _) = _, %v, want _, %v", err, errCredentialsMisuse)
 	}
 }