Struct lbBalancer

balancer/grpclb/grpclb.go:177–239

}

type lbBalancer struct {
	cc         *lbCacheClientConn
	dialTarget string // user's dial target
	target     string // same as dialTarget unless overridden in service config
	opt        balancer.BuildOptions
	logger     *internalgrpclog.PrefixLogger

	usePickFirst bool

	// grpclbClientConnCreds is the creds bundle to be used to connect to grpclb
	// servers. If it's nil, use the TransportCredentials from BuildOptions
	// instead.
	grpclbClientConnCreds credentials.Bundle
	// grpclbBackendCreds is the creds bundle to be used for addresses that are
	// returned by grpclb server. If it's nil, don't set anything when creating
	// SubConns.
	grpclbBackendCreds credentials.Bundle

	fallbackTimeout time.Duration
	doneCh          chan struct{}

	// manualResolver is used in the remote LB ClientConn inside grpclb. When
	// resolved address updates are received by grpclb, filtered updates will be
	// sent to remote LB ClientConn through this resolver.
	manualResolver *manual.Resolver
	// The ClientConn to talk to the remote balancer.
	ccRemoteLB *remoteBalancerCCWrapper
	// backoff for calling remote balancer.
	backoff backoff.Strategy

	// Support client side load reporting. Each picker gets a reference to this,
	// and will update its content.
	clientStats *rpcStats

	mu sync.Mutex // guards everything following.
	// The full server list including drops, used to check if the newly received
	// serverList contains anything new. Each generate picker will also have
	// reference to this list to do the first layer pick.
	fullServerList []*lbpb.Server
	// Backend addresses. It's kept so the addresses are available when
	// switching between round_robin and pickfirst.
	backendAddrs []resolver.Address
	// All backends addresses, with metadata set to nil. This list contains all
	// backend addresses in the same order and with the same duplicates as in
	// serverlist. When generating picker, a SubConn slice with the same order
	// but with only READY SCs will be generated.
	backendAddrsWithoutMetadata []resolver.Address
	// Roundrobin functionalities.
	state    connectivity.State
	subConns map[resolver.Address]balancer.SubConn   // Used to new/shutdown SubConn.
	scStates map[balancer.SubConn]connectivity.State // Used to filter READY SubConns.
	picker   balancer.Picker
	// Support fallback to resolved backend addresses if there's no response
	// from remote balancer within fallbackTimeout.
	remoteBalancerConnected bool
	serverListReceived      bool
	inFallback              bool
	// resolvedBackendAddrs is resolvedAddrs minus remote balancers. It's set