coordt

Documentation

Index

• Variables
• type Message
• type Node
• type QueryFunc
• type QueryID
• type QueryStats
• type Router
• type StateMachine
• type Value

Variables

var (
	ErrNodeNotFound     = errors.New("node not found")
	ErrValueNotFound    = errors.New("value not found")
	ErrValueNotAccepted = errors.New("value not accepted")
)

var (
	// ErrSkipNode is used as a return value from a QueryFunc to indicate that the node is to be skipped.
	ErrSkipNode = errors.New("skip node")

	// ErrSkipRemaining is used as a return value a QueryFunc to indicate that all remaining nodes are to be skipped.
	ErrSkipRemaining = errors.New("skip remaining nodes")
)

Types

type Message

type Message interface{}

type Node

type Node interface {
	// ID returns the peer ID identifying this node.
	ID() kadt.PeerID

	// GetClosestNodes requests the n closest nodes to the key from the node's
	// local routing table. The node may return fewer nodes than requested.
	GetClosestNodes(ctx context.Context, key kadt.Key, n int) ([]Node, error)

	// GetValue requests that the node return any value associated with the
	// supplied key. If the node does not have a value for the key it returns
	// ErrValueNotFound.
	GetValue(ctx context.Context, key kadt.Key) (Value, error)

	// PutValue requests that the node stores a value to be associated with the supplied key.
	// If the node cannot or chooses not to store the value for the key it returns ErrValueNotAccepted.
	PutValue(ctx context.Context, r Value, q int) error
}

Node represents the local or a remote node participating in the DHT.

type QueryFunc

type QueryFunc func(ctx context.Context, id kadt.PeerID, resp *pb.Message, stats QueryStats) error

QueryFunc is the type of the function called by Query to visit each node.

The error result returned by the function controls how Query proceeds. If the function returns the special value SkipNode, Query skips fetching closer nodes from the current node. If the function returns the special value SkipRemaining, Query skips all visiting all remaining nodes. Otherwise, if the function returns a non-nil error, Query stops entirely and returns that error.

The stats argument contains statistics on the progress of the query so far.

type QueryID

type QueryID string

TODO: rename to something like OperationID. This type isn't only used to identify queries but also other operations like broadcasts.

const InvalidQueryID QueryID = ""

type QueryStats

type QueryStats struct {
	Start     time.Time // Start is the time the query began executing.
	End       time.Time // End is the time the query stopped executing.
	Requests  int       // Requests is a count of the number of requests made by the query.
	Success   int       // Success is a count of the number of nodes the query succesfully contacted.
	Failure   int       // Failure is a count of the number of nodes the query received an error response from.
	Exhausted bool      // Exhausted is true if the query ended after visiting every node it could.
}

type Router

type Router[K kad.Key[K], N kad.NodeID[K], M Message] interface {
	// SendMessage attempts to send a request to another node. This method blocks until a response is received or an error is encountered.
	SendMessage(ctx context.Context, to N, req M) (M, error)

	// GetClosestNodes attempts to send a request to another node asking it for nodes that it considers to be
	// closest to the target key.
	GetClosestNodes(ctx context.Context, to N, target K) ([]N, error)
}

type StateMachine

type StateMachine[E any, S any] interface {
	Advance(context.Context, E) S
}

type Value

type Value interface {
	Key() kadt.Key
	MarshalBinary() ([]byte, error)
}

Value is a value that may be stored in the DHT.