Method exitIdleMode

clientconn.go:394–423

exitIdleMode moves the channel out of idle mode by recreating the name resolver and load balancer. This should never be called directly; use cc.idlenessMgr.ExitIdleMode instead.

()

// resolver and load balancer.  This should never be called directly; use
// cc.idlenessMgr.ExitIdleMode instead.
func (cc *ClientConn) exitIdleMode() error {
	cc.mu.Lock()
	if cc.conns == nil {
		cc.mu.Unlock()
		return errConnClosing
	}
	cc.mu.Unlock()

	// Set state to CONNECTING before building the name resolver
	// so the channel does not remain in IDLE.
	cc.csMgr.updateState(connectivity.Connecting)

	// This needs to be called without cc.mu because this builds a new resolver
	// which might update state or report error inline, which would then need to
	// acquire cc.mu.
	if err := cc.resolverWrapper.start(); err != nil {
		// If resolver creation fails, treat it like an error reported by the
		// resolver before any valid updates. Set channel's state to
		// TransientFailure, and set an erroring picker with the resolver build
		// error, which will returned as part of any subsequent RPCs.
		logger.Warningf("Failed to start resolver: %v", err)
		cc.csMgr.updateState(connectivity.TransientFailure)
		cc.mu.Lock()
		cc.updateResolverStateAndUnlock(resolver.State{}, err)
		return fmt.Errorf("failed to start resolver: %w", err)
	}

	cc.addTraceEvent("exiting idle mode")
	return nil
}

// initIdleStateLocked initializes common state to how it should be while idle.
func (cc *ClientConn) initIdleStateLocked() {