Documentation
¶
Overview ¶
Package balancergroup implements a utility struct to bind multiple balancers into one balancer.
Index ¶
- Variables
- type BalancerGroup
- func (bg *BalancerGroup) Add(id string, builder balancer.Builder)
- func (bg *BalancerGroup) Close()
- func (bg *BalancerGroup) ExitIdle()
- func (bg *BalancerGroup) Remove(id string)
- func (bg *BalancerGroup) ResolverError(err error)
- func (bg *BalancerGroup) Start()
- func (bg *BalancerGroup) UpdateClientConnState(id string, s balancer.ClientConnState) error
- func (bg *BalancerGroup) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState)
- type BalancerStateAggregator
Constants ¶
This section is empty.
Variables ¶
var DefaultSubBalancerCloseTimeout = 15 * time.Minute
DefaultSubBalancerCloseTimeout is defined as a variable instead of const for testing.
TODO: make it a parameter for New().
Functions ¶
This section is empty.
Types ¶
type BalancerGroup ¶
type BalancerGroup struct {
// contains filtered or unexported fields
}
BalancerGroup takes a list of balancers, and make them into one balancer.
Note that this struct doesn't implement balancer.Balancer, because it's not intended to be used directly as a balancer. It's expected to be used as a sub-balancer manager by a high level balancer.
Updates from ClientConn are forwarded to sub-balancers
- service config update
- Not implemented
- address update
- subConn state change
- find the corresponding balancer and forward
Actions from sub-balances are forwarded to parent ClientConn
- new/remove SubConn
- picker update and health states change
- sub-pickers are sent to an aggregator provided by the parent, which will group them into a group-picker. The aggregated connectivity state is also handled by the aggregator.
- resolveNow
Sub-balancers are only built when the balancer group is started. If the balancer group is closed, the sub-balancers are also closed. And it's guaranteed that no updates will be sent to parent ClientConn from a closed balancer group.
func New ¶
func New(cc balancer.ClientConn, bOpts balancer.BuildOptions, stateAggregator BalancerStateAggregator, loadStore load.PerClusterReporter, logger *grpclog.PrefixLogger) *BalancerGroup
New creates a new BalancerGroup. Note that the BalancerGroup needs to be started to work.
TODO(easwars): Pass an options struct instead of N args.
func (*BalancerGroup) Add ¶
func (bg *BalancerGroup) Add(id string, builder balancer.Builder)
Add adds a balancer built by builder to the group, with given id.
func (*BalancerGroup) Close ¶
func (bg *BalancerGroup) Close()
Close closes the balancer. It stops sub-balancers, and removes the subconns. The BalancerGroup can be restarted later.
func (*BalancerGroup) ExitIdle ¶ added in v1.41.0
func (bg *BalancerGroup) ExitIdle()
ExitIdle should be invoked when the parent LB policy's ExitIdle is invoked. It will trigger this on all sub-balancers, or reconnect their subconns if not supported.
func (*BalancerGroup) Remove ¶
func (bg *BalancerGroup) Remove(id string)
Remove removes the balancer with id from the group.
But doesn't close the balancer. The balancer is kept in a cache, and will be closed after timeout. Cleanup work (closing sub-balancer and removing subconns) will be done after timeout.
func (*BalancerGroup) ResolverError ¶ added in v1.30.0
func (bg *BalancerGroup) ResolverError(err error)
ResolverError forwards resolver errors to all sub-balancers.
func (*BalancerGroup) Start ¶
func (bg *BalancerGroup) Start()
Start starts the balancer group, including building all the sub-balancers, and send the existing addresses to them.
A BalancerGroup can be closed and started later. When a BalancerGroup is closed, it can still receive address updates, which will be applied when restarted.
func (*BalancerGroup) UpdateClientConnState ¶ added in v1.30.0
func (bg *BalancerGroup) UpdateClientConnState(id string, s balancer.ClientConnState) error
UpdateClientConnState handles ClientState (including balancer config and addresses) from resolver. It finds the balancer and forwards the update.
func (*BalancerGroup) UpdateSubConnState ¶ added in v1.30.0
func (bg *BalancerGroup) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState)
UpdateSubConnState handles the state for the subconn. It finds the corresponding balancer and forwards the update.
type BalancerStateAggregator ¶ added in v1.31.0
type BalancerStateAggregator interface {
// UpdateState updates the state of the id.
//
// It's up to the implementation whether this will trigger an update to the
// parent ClientConn.
UpdateState(id string, state balancer.State)
}
BalancerStateAggregator aggregates sub-picker and connectivity states into a state.
It takes care of merging sub-picker into one picker. The picking config is passed directly from the the parent to the aggregator implementation (instead via balancer group).
Source Files