Method updateConnectivityState

clientconn.go:1279–1308

Note: this requires a lock on ac.mu.

(s connectivity.State, lastErr error)

// Note: this requires a lock on ac.mu.
func (ac *addrConn) updateConnectivityState(s connectivity.State, lastErr error) {
	if ac.state == s {
		return
	}

	// If we are transitioning out of Ready, it means there is a disconnection.
	// A SubConn can also transition from CONNECTING directly to IDLE when
	// a transport is successfully created, but the connection fails
	// before the SubConn can send the notification for READY. We treat
	// this as a successful connection and transition to IDLE.
	// TODO: https://github.com/grpc/grpc-go/issues/7862 - Remove the second
	// part of the if condition below once the issue is fixed.
	if ac.state == connectivity.Ready || (ac.state == connectivity.Connecting && s == connectivity.Idle) {
		disconnectError := ac.disconnectErrorLabel
		if disconnectError == "" {
			disconnectError = "unknown"
		}
		disconnectionsMetric.Record(ac.cc.metricsRecorderList, 1, ac.cc.target, ac.backendServiceLabel, ac.localityLabel, disconnectError)
		openConnectionsMetric.Record(ac.cc.metricsRecorderList, -1, ac.cc.target, ac.backendServiceLabel, ac.securityLevelLocked(), ac.localityLabel)
	}
	ac.disconnectErrorLabel = "" // Reset for next time
	ac.state = s
	ac.channelz.ChannelMetrics.State.Store(&s)
	if lastErr == nil {
		channelz.Infof(logger, ac.channelz, "Subchannel Connectivity change to %v", s)
	} else {
		channelz.Infof(logger, ac.channelz, "Subchannel Connectivity change to %v, last error: %s", s, lastErr)
	}
	ac.acbw.updateState(s, lastErr)
}

// adjustParams updates parameters used to create transports upon
// receiving a GoAway.