selector

Documentation

Index

• Variables
• type Balancer
• type BalancerBuilder
• type Builder
• type Default
  • func (d *Default) Apply(nodes []Node)
  • func (d *Default) Select(ctx context.Context, opts ...SelectOption) (selected Node, done DoneFunc, err error)
• type DefaultBuilder
  • func (db *DefaultBuilder) Build() Selector
• type DoneFunc
• type DoneInfo
• type Filter
• type Node
• type Rebalancer
• type ReplyMeta
• type SelectOption
  • func WithFilter(fn ...Filter) SelectOption
• type SelectOptions
• type Selector
• type WeightedNode
• type WeightedNodeBuilder

Variables

var ErrNoAvailable = errors.ServiceUnavailable("no_available_node", "")

ErrNoAvailable is no available node.

Types

type Balancer

type Balancer interface {
	Pick(ctx context.Context, nodes []WeightedNode) (selected WeightedNode, done DoneFunc, err error)
}

Balancer is balancer interface

type BalancerBuilder

type BalancerBuilder interface {
	Build() Balancer
}

BalancerBuilder build balancer

type Builder

type Builder interface {
	Build() Selector
}

Builder build selector

type Default

type Default struct {
	NodeBuilder WeightedNodeBuilder
	Balancer    Balancer
	Filters     []Filter
	// contains filtered or unexported fields
}

Default is composite selector.

func (*Default) Apply

func (d *Default) Apply(nodes []Node)

Apply update nodes info.

func (*Default) Select

func (d *Default) Select(ctx context.Context, opts ...SelectOption) (selected Node, done DoneFunc, err error)

Select select one node.

type DefaultBuilder

type DefaultBuilder struct {
	Node     WeightedNodeBuilder
	Balancer BalancerBuilder
	Filters  []Filter
}

DefaultBuilder is de

func (*DefaultBuilder) Build

func (db *DefaultBuilder) Build() Selector

Build create builder

type DoneFunc

type DoneFunc func(ctx context.Context, di DoneInfo)

DoneFunc is callback function when RPC invoke done.

type DoneInfo

type DoneInfo struct {
	// Response Error
	Err error
	// Response Metadata
	ReplyMeta ReplyMeta

	// BytesSent indicates if any bytes have been sent to the server.
	BytesSent bool
	// BytesReceived indicates if any byte has been received from the server.
	BytesReceived bool
}

DoneInfo is callback info when RPC invoke done.

type Filter

type Filter func(context.Context, []Node) []Node

Filter is node filter function.

type Node

type Node interface {
	// Address is the unique address under the same service
	Address() string

	// ServiceName is service name
	ServiceName() string

	// InitialWeight is the initial value of scheduling weight
	// if not set return nil
	InitialWeight() *int64

	// Version is service node version
	Version() string

	// Metadata is the kv pair metadata associated with the service instance.
	// version,namespace,region,protocol etc..
	Metadata() map[string]string
}

Node is node interface.

type Rebalancer

type Rebalancer interface {
	// apply all nodes when any changes happen
	Apply(nodes []Node)
}

Rebalancer is nodes rebalancer.

type ReplyMeta

type ReplyMeta interface {
	Get(key string) string
}

ReplyMeta is Reply Metadata.

type SelectOption

type SelectOption func(*SelectOptions)

SelectOption is Selector option.

func WithFilter

func WithFilter(fn ...Filter) SelectOption

WithFilter with filter options

type SelectOptions

type SelectOptions struct {
	Filters []Filter
}

SelectOptions is Select Options.

type Selector

type Selector interface {
	Rebalancer

	// Select nodes
	// if err == nil, selected and done must not be empty.
	Select(ctx context.Context, opts ...SelectOption) (selected Node, done DoneFunc, err error)
}

Selector is node pick balancer.

type WeightedNode

type WeightedNode interface {
	Node

	// Weight is the runtime calculated weight
	Weight() float64

	// Pick the node
	Pick() DoneFunc

	// PickElapsed is time elapsed since the latest pick
	PickElapsed() time.Duration
}

WeightedNode calculates scheduling weight in real time

type WeightedNodeBuilder

type WeightedNodeBuilder interface {
	Build(Node) WeightedNode
}

WeightedNodeBuilder is WeightedNode Builder