Method updateAddrs

clientconn.go:1018–1075

updateAddrs updates ac.addrs with the new addresses list and handles active connections or connection attempts.

(addrs []resolver.Address)

// updateAddrs updates ac.addrs with the new addresses list and handles active
// connections or connection attempts.
func (ac *addrConn) updateAddrs(addrs []resolver.Address) {
	addrs = copyAddresses(addrs)
	limit := len(addrs)
	if limit > 5 {
		limit = 5
	}
	channelz.Infof(logger, ac.channelz, "addrConn: updateAddrs addrs (%d of %d): %v", limit, len(addrs), addrs[:limit])

	ac.mu.Lock()
	if equalAddressesIgnoringBalAttributes(ac.addrs, addrs) {
		ac.mu.Unlock()
		return
	}

	ac.addrs = addrs
	ac.updateTelemetryLabelsLocked()
	if ac.state == connectivity.Shutdown ||
		ac.state == connectivity.TransientFailure ||
		ac.state == connectivity.Idle {
		// We were not connecting, so do nothing but update the addresses.
		ac.mu.Unlock()
		return
	}

	if ac.state == connectivity.Ready {
		// Try to find the connected address.
		for _, a := range addrs {
			a.ServerName = ac.cc.getServerName(a)
			if equalAddressIgnoringBalAttributes(&a, &ac.curAddr) {
				// We are connected to a valid address, so do nothing but
				// update the addresses.
				ac.mu.Unlock()
				return
			}
		}
	}

	// We are either connected to the wrong address or currently connecting.
	// Stop the current iteration and restart.

	ac.cancel()
	ac.ctx, ac.cancel = context.WithCancel(ac.cc.ctx)

	// We have to defer here because GracefulClose => onClose, which requires
	// locking ac.mu.
	if ac.transport != nil {
		defer ac.transport.GracefulClose()
		ac.transport = nil
	}

	if len(addrs) == 0 {
		ac.updateConnectivityState(connectivity.Idle, nil)
	}

	// Since we were connecting/connected, we should start a new connection
	// attempt.
	go ac.resetTransportAndUnlock()
}