replica

Documentation

Overview

Package replica extends Ringpop functionality by providing a mechanism to replicate a request to multiple nodes in the ring.

Index

• type FanoutMode
• type Options
• type Replicator
  • func NewReplicator(s Sender, channel shared.SubChannel, logger log.Logger, opts *Options) *Replicator
  • func (r *Replicator) Read(keys []string, request []byte, operation string, fopts *forward.Options, ...) (responses []Response, err error)
  • func (r *Replicator) Write(keys []string, request []byte, operation string, fopts *forward.Options, ...) (responses []Response, err error)
• type Response
• type Sender

Types

type FanoutMode

type FanoutMode int

FanoutMode defines how a replicator should fanout it's requests

const (
	// Parallel fanout mode for replicator read write requests. Sends out requests
	// in parallel.
	Parallel FanoutMode = iota

	// SerialSequential fanout mode for replicator read write requests. Sends out
	// requests one at a time going through the preference list sequentially
	SerialSequential

	// SerialBalanced fanout mode for replicator read write requests. Sends out
	// requests one at a time, going through the preference list in a random order
	SerialBalanced
)

type Options

type Options struct {
	NValue, RValue, WValue int
	FanoutMode             FanoutMode
}

Options for sending a read/write replicator request

type Replicator

type Replicator struct {
	// contains filtered or unexported fields
}

A Replicator is used to replicate a request across nodes such that they share ownership of some data.

func NewReplicator

func NewReplicator(s Sender, channel shared.SubChannel, logger log.Logger,
	opts *Options) *Replicator

NewReplicator returns a new Replicator instance that makes calls with the given SubChannel to the service defined by SubChannel.GetServiceName(). The given n/w/r values will be used as defaults for the replicator when none are provided

func (*Replicator) Read

func (r *Replicator) Read(keys []string, request []byte, operation string, fopts *forward.Options,
	opts *Options) (responses []Response, err error)

Read replicates a read request. It takes key(s) to be used for lookup of the requests destination, a request to send, the operation to perform at the destination, options for forwarding the request as well as options for ffanning out the request. It also takes a response type, which is the type of struct that will be returned in each responses.Body in response. Response type must be a concrete struct. The body field will contain a pointer to that type of struct.

func (*Replicator) Write

func (r *Replicator) Write(keys []string, request []byte, operation string, fopts *forward.Options,
	opts *Options) (responses []Response, err error)

Write replicates a write request. It takes key(s) to be used for lookup of the requests destination, a request to send, the operation to perform at the destination, options for forwarding the request as well as options for ffanning out the request. It also takes a response type, which is the type of struct that will be returned in each responses.Body in response. Response type must be a concrete struct. The body field will contain a pointer to that type of struct.

type Response

type Response struct {
	Destination string
	Keys        []string
	Body        []byte
}

A Response is a response from a replicator read/write request.

type Sender

type Sender interface {
	// Lookup should return a server address
	Lookup(string) (string, error)

	// LookupN should return n server addresses
	LookupN(string, int) ([]string, error)

	// WhoAmI should return the local address of the sender
	WhoAmI() (string, error)
}

A Sender is used to lookup the destinations for requests given a key.