grpc

package
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Published: Jun 30, 2021 License: Apache-2.0 Imports: 19 Imported by: 0

Documentation

Overview

Package grpc provides nodes grpc connection utilities.

Index

Constants

This section is empty.

Variables

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var ErrNotVersionedWatcher = fmt.Errorf("client watcher is not versioned")

ErrNotVersionedWatcher is an error returned when versioned specific methods are called for a non-versioned client.

Functions

This section is empty.

Types

type ConnWithNodeMeta

type ConnWithNodeMeta struct {
	*grpc.ClientConn

	Node *node.Node
}

ConnWithNodeMeta is a gRPC client connection together with node metadata.

type NodeSelectionFeedback

type NodeSelectionFeedback struct {
	// ID is the node identifier.
	ID signature.PublicKey

	// Bad being non-nil signals that the currently selected node is bad and contains the reason
	// that lead to the decision.
	Bad error
}

NodeSelectionFeedback is feedback to the node selection policy.

type NodeSelectionPolicy

type NodeSelectionPolicy interface {
	// UpdateNodes updates the set of available nodes.
	UpdateNodes([]signature.PublicKey)

	// UpdatePolicy submits feedback to the policy which can cause the policy to update its current
	// node selection.
	UpdatePolicy(feedback NodeSelectionFeedback)

	// Pick picks a node from the set of available nodes accoording to the policy.
	Pick() signature.PublicKey
}

NodeSelectionPolicy is a node selection policy.

func NewRoundRobinNodeSelectionPolicy

func NewRoundRobinNodeSelectionPolicy() NodeSelectionPolicy

NewRoundRobinNodeSelectionPolicy creates a new round-robin node selection policy.

type NodesClient

type NodesClient interface {
	// GetConnections returns the set of connections to nodes.
	GetConnections() []*grpc.ClientConn

	// GetConnectionsWithMeta returns the set of connections to nodes including node metadata
	// for each connection.
	GetConnectionsWithMeta() []*ConnWithNodeMeta

	// GetConnectionsMap returns the set of connections to nodes including node metadata
	// for each connection.
	GetConnectionsMap() map[signature.PublicKey]*ConnWithNodeMeta

	// GetConnection returns a connection based on the configured node selection policy.
	//
	// If no connections are available this method will return nil.
	GetConnection() *grpc.ClientConn

	// UpdateNodeSelectionPolicy submits feedback to the policy which can cause the policy to update
	// its current node selection.
	UpdateNodeSelectionPolicy(feedback NodeSelectionFeedback)

	// EnsureVersion waits for the client to be fully synced to the given watcher version.
	//
	// When client is using a non-versioned watcher, this method should return ErrNotVersionedWatcher error.
	EnsureVersion(ctx context.Context, version int64) error

	// Initialized returns a channel that will be closed once the first connection is available.
	Initialized() <-chan struct{}
}

NodesClient is a node gRPC client interface. It automatically maintains gRPC connections to all nodes as directed by the node watcher.

func NewNodesClient

func NewNodesClient(ctx context.Context, nw nodes.NodeDescriptorLookup, options ...Option) (NodesClient, error)

NewNodesClient creates a new nodes gRPC client.

type Option

type Option func(nc *nodesClient)

Option is an option for NewNodesClient.

func WithClientAuthentication

func WithClientAuthentication(identity *identity.Identity) Option

WithClientAuthentication is an option for configuring client authentication on TLS connections.

func WithCloseDelay

func WithCloseDelay(delay time.Duration) Option

WithCloseDelay is an option for configuring the connection close delay after rotating a connection.

If not configured it defaults to 5 seconds.

func WithNodeSelectionPolicy

func WithNodeSelectionPolicy(policy NodeSelectionPolicy) Option

WithNodeSelectionPolicy is an option for configuring the node selection policy.

If not configured it defaults to the round-robin policy.

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