epaxos

Documentation

Index

• Variables
• type Config
• type DefaultLogger
  • func NewDefaultLogger() *DefaultLogger
  • func (l *DefaultLogger) Debug(v ...interface{})
  • func (l *DefaultLogger) Debugf(format string, v ...interface{})
  • func (l *DefaultLogger) EnableDebug()
  • func (l *DefaultLogger) Error(v ...interface{})
  • func (l *DefaultLogger) Errorf(format string, v ...interface{})
  • func (l *DefaultLogger) Fatal(v ...interface{})
  • func (l *DefaultLogger) Fatalf(format string, v ...interface{})
  • func (l *DefaultLogger) Info(v ...interface{})
  • func (l *DefaultLogger) Infof(format string, v ...interface{})
  • func (l *DefaultLogger) Panic(v ...interface{})
  • func (l *DefaultLogger) Panicf(format string, v ...interface{})
  • func (l *DefaultLogger) Warning(v ...interface{})
  • func (l *DefaultLogger) Warningf(format string, v ...interface{})
• type Logger
• type MemoryStorage
  • func (ms *MemoryStorage) HardState() (pb.HardState, bool)
  • func (ms *MemoryStorage) Instances() []*pb.InstanceState
  • func (ms *MemoryStorage) PersistHardState(hs pb.HardState)
  • func (ms *MemoryStorage) PersistInstance(is *pb.InstanceState)
• type Node
  • func StartNode(c *Config) Node
• type Ready
• type Storage
  • func NewMemoryStorage(c *Config) Storage

Variables

var (
	// ErrStopped is returned by methods on Nodes that have been stopped.
	ErrStopped = errors.New("epaxos: stopped")
)

Types

type Config

type Config struct {
	// ID is the identity of the local epaxos.
	ID pb.ReplicaID
	// Nodes is the set of all nodes in the epaxos network.
	Nodes []pb.ReplicaID
	// Storage is the persistent storage for epaxos. epaxos reads out
	// the previous instance state and configuration from storage when
	// restarting.
	Storage Storage
	// Logger is the logger that the epaxos state machine will use
	// to log events. If not set, a default logger will be used.
	Logger Logger
	// RandSeed allows the seed used by epaxos's rand.Source to be
	// injected, to allow for fully deterministic execution.
	RandSeed int64
}

Config contains the parameters to start epaxos.

type DefaultLogger

type DefaultLogger struct {
	*log.Logger
	// contains filtered or unexported fields
}

DefaultLogger is a default implementation of the Logger interface.

func NewDefaultLogger

func NewDefaultLogger() *DefaultLogger

NewDefaultLogger creates a default logger that prints to stderr.

func (*DefaultLogger) Debug

func (l *DefaultLogger) Debug(v ...interface{})

Debug implements the Logger interface.

func (*DefaultLogger) Debugf

func (l *DefaultLogger) Debugf(format string, v ...interface{})

Debugf implements the Logger interface.

func (*DefaultLogger) EnableDebug

func (l *DefaultLogger) EnableDebug()

EnableDebug enables debug messages to print.

func (*DefaultLogger) Error

func (l *DefaultLogger) Error(v ...interface{})

Error implements the Logger interface.

func (*DefaultLogger) Errorf

func (l *DefaultLogger) Errorf(format string, v ...interface{})

Errorf implements the Logger interface.

func (*DefaultLogger) Fatal

func (l *DefaultLogger) Fatal(v ...interface{})

Fatal implements the Logger interface.

func (*DefaultLogger) Fatalf

func (l *DefaultLogger) Fatalf(format string, v ...interface{})

Fatalf implements the Logger interface.

func (*DefaultLogger) Info

func (l *DefaultLogger) Info(v ...interface{})

Info implements the Logger interface.

func (*DefaultLogger) Infof

func (l *DefaultLogger) Infof(format string, v ...interface{})

Infof implements the Logger interface.

func (*DefaultLogger) Panic

func (l *DefaultLogger) Panic(v ...interface{})

Panic implements the Logger interface.

func (*DefaultLogger) Panicf

func (l *DefaultLogger) Panicf(format string, v ...interface{})

Panicf implements the Logger interface.

func (*DefaultLogger) Warning

func (l *DefaultLogger) Warning(v ...interface{})

Warning implements the Logger interface.

func (*DefaultLogger) Warningf

func (l *DefaultLogger) Warningf(format string, v ...interface{})

Warningf implements the Logger interface.

type Logger

type Logger interface {
	Debug(v ...interface{})
	Debugf(format string, v ...interface{})

	Error(v ...interface{})
	Errorf(format string, v ...interface{})

	Info(v ...interface{})
	Infof(format string, v ...interface{})

	Warning(v ...interface{})
	Warningf(format string, v ...interface{})

	Fatal(v ...interface{})
	Fatalf(format string, v ...interface{})

	Panic(v ...interface{})
	Panicf(format string, v ...interface{})
}

Logger provides a logging interface similar to golang's standard Logger.

type MemoryStorage

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

MemoryStorage implements the Storage interface backed by an in-memory data structure.

func (*MemoryStorage) HardState

func (ms *MemoryStorage) HardState() (pb.HardState, bool)

HardState implements the Storage interface.

func (*MemoryStorage) Instances

func (ms *MemoryStorage) Instances() []*pb.InstanceState

Instances implements the Storage interface.

func (*MemoryStorage) PersistHardState

func (ms *MemoryStorage) PersistHardState(hs pb.HardState)

PersistHardState implements the Storage interface.

func (*MemoryStorage) PersistInstance

func (ms *MemoryStorage) PersistInstance(is *pb.InstanceState)

PersistInstance implements the Storage interface.

type Node

type Node interface {
	// Tick increments the internal logical clock for the Node by a single tick.
	// Election timeouts and progress timeouts are in units of ticks.
	Tick()
	// Propose proposes that data be ordered by paxos.
	Propose(ctx context.Context, command pb.Command) error
	// Step advances the state machine using the given message. ctx.Err() will be
	// returned, if any.
	Step(ctx context.Context, msg pb.Message) error
	// Ready returns a channel that returns the current point-in-time state.
	// Users of the Node must call Advance after retrieving the state returned by
	// Ready.
	//
	// NOTE: No committed entries from the next Ready may be applied until all
	// committed entries and snapshots from the previous one have finished.
	Ready() <-chan Ready
	// Stop performs any necessary termination of the Node.
	Stop()
}

Node represents a node in a paxos cluster.

func StartNode

func StartNode(c *Config) Node

StartNode returns a new Node with the given configuration.

type Ready

type Ready struct {
	// Messages specifies outbound messages to be sent AFTER Entries are
	// committed to stable storage.
	Messages []pb.Message

	// ExecutedCommands specifies commands to be executed by a state-machine.
	// These have previously been committed to stable store.
	ExecutedCommands []pb.Command
}

Ready encapsulates the entries and messages that are ready to read, be saved to stable storage, committed or sent to other peers. All fields in Ready are read-only.

type Storage

type Storage interface {
	HardState() (pb.HardState, bool)
	PersistHardState(hs pb.HardState)

	Instances() []*pb.InstanceState
	PersistInstance(is *pb.InstanceState)
}

Storage allows for the persistence of EPaxos state to provide durability.

func NewMemoryStorage

func NewMemoryStorage(c *Config) Storage

NewMemoryStorage returns a new in-memory implementation of Storage using the provided Config.