storage

Documentation

Overview

Package storage contains the interface for storing and retrieving data about the state of the mesh and providing storage backends for raft.

Index

• Variables
• func IsKeyNotFoundError(err error) bool
• func NewKeyNotFoundError(key string) error
• func RunDualStorageConformance(t *testing.T, dualStorage DualStorage)
• func RunMeshStorageConformance(t *testing.T, meshStorage MeshStorage)
• func RunRaftStorageConformance(t *testing.T, raftStorage RaftStorage)
• type DualStorage
• type MeshStorage
• type PrefixIterator
• type RaftStorage
• type SubscribeFunc

Variables

var ErrKeyNotFound = errors.New("key not found")

ErrKeyNotFound is the error returned when a key is not found.

Functions

func IsKeyNotFoundError

func IsKeyNotFoundError(err error) bool

IsKeyNotFoundError returns true if the given error is a ErrKeyNotFound error.

func NewKeyNotFoundError

func NewKeyNotFoundError(key string) error

NewKeyNotFoundError returns a new ErrKeyNotFound error.

func RunDualStorageConformance

func RunDualStorageConformance(t *testing.T, dualStorage DualStorage)

RunDualStorageConformance tests that the DualStorage interface is implemented correctly.

func RunMeshStorageConformance

func RunMeshStorageConformance(t *testing.T, meshStorage MeshStorage)

RunMeshStorageConformance tests that the MeshStorage interface is implemented correctly.

func RunRaftStorageConformance

func RunRaftStorageConformance(t *testing.T, raftStorage RaftStorage)

RunRaftStorageConformance tests that the RaftStorage interface is implemented correctly.

Types

type DualStorage

type DualStorage interface {
	MeshStorage
	RaftStorage
}

DualStorage represents a storage interface that can serve as both a mesh and Raft storage.

type MeshStorage

type MeshStorage interface {
	// GetValue returns the value of a key.
	GetValue(ctx context.Context, key string) (string, error)
	// PutValue sets the value of a key. TTL is optional and can be set to 0.
	PutValue(ctx context.Context, key, value string, ttl time.Duration) error
	// Delete removes a key.
	Delete(ctx context.Context, key string) error
	// List returns all keys with a given prefix.
	List(ctx context.Context, prefix string) ([]string, error)
	// IterPrefix iterates over all keys with a given prefix. It is important
	// that the iterator not attempt any write operations as this will cause
	// a deadlock. The iteration will stop if the iterator returns an error.
	IterPrefix(ctx context.Context, prefix string, fn PrefixIterator) error
	// Snapshot returns a snapshot of the storage.
	Snapshot(ctx context.Context) (io.Reader, error)
	// Restore restores a snapshot of the storage.
	Restore(ctx context.Context, r io.Reader) error
	// Subscribe will call the given function whenever a key with the given prefix is changed.
	// The returned function can be called to unsubscribe.
	Subscribe(ctx context.Context, prefix string, fn SubscribeFunc) (context.CancelFunc, error)
	// Close closes the storage.
	Close() error
}

MeshStorage is the interface for storing and retrieving data about the state of the mesh.

type PrefixIterator

type PrefixIterator func(key, value string) error

PrefixIterator is the function signature for iterating over all keys with a given prefix.

type RaftStorage

type RaftStorage interface {
	raft.LogStore
	raft.StableStore
	io.Closer
}

RaftStorage is the interface for storing and retrieving data about the state of the mesh. This interface is used by mesh members that are part of the Raft cluster.

type SubscribeFunc

type SubscribeFunc func(key, value string)

SubscribeFunc is the function signature for subscribing to changes to a key.