Rename ConnMaxChannels to ConnMaxSessions; make default 65536

conn.go

@@ -15,7 +15,7 @@ import (
 const (
 	DefaultMaxFrameSize = 512
 	DefaultIdleTimeout  = 1 * time.Minute
-	DefaultMaxChannel   = 1
+	DefaultMaxSessions  = 65536
 )
 
 // Errors
@@ -107,14 +107,24 @@ func ConnConnectTimeout(d time.Duration) ConnOption {
 	return func(c *conn) error { c.connectTimeout = d; return nil }
 }
 
-// ConnMaxChannels sets the maximum channel number.
+// ConnMaxSessions sets the maximum number of channels.
 //
-// Channel numbering starts at zero.
+// n must be in the range 1 to 65536.
 //
-// Default: 1.
-func ConnMaxChannels(n uint16) ConnOption {
+// BUG: Currently this limits how many channels can ever
+//      be opened on this connection rather than how many
+//      channels can be open at the same time.
+//
+// Default: 65536.
+func ConnMaxSessions(n int) ConnOption {
 	return func(c *conn) error {
-		c.channelMax = n
+		if n < 1 {
+			return errorNew("max sessions cannot be less than 1")
+		}
+		if n > 65536 {
+			return errorNew("max sessions cannot be greater than 65536")
+		}
+		c.channelMax = uint16(n - 1)
 		return nil
 	}
 }
@@ -178,7 +188,7 @@ func newConn(netConn net.Conn, opts ...ConnOption) (*conn, error) {
 		net:              netConn,
 		maxFrameSize:     DefaultMaxFrameSize,
 		peerMaxFrameSize: DefaultMaxFrameSize,
-		channelMax:       DefaultMaxChannel,
+		channelMax:       DefaultMaxSessions - 1, // -1 because channel-max starts at zero
 		idleTimeout:      DefaultIdleTimeout,
 		done:             make(chan struct{}),
 		connErr:          make(chan error, 2), // buffered to ensure connReader/Writer won't leak

integration_test.go

@@ -91,7 +91,7 @@ func TestIntegrationRoundTrip(t *testing.T) {
 
 			// Create client
 			client := newClient(t, tt.label,
-				amqp.ConnMaxChannels(uint16(tt.sessions-1)),
+				amqp.ConnMaxSessions(tt.sessions),
 			)
 			defer client.Close()