redis

README

Valkeyrie Redis

valkeyrie provides a Go native library to store metadata using Distributed Key/Value stores (or common databases).

Compatibility

A storage backend in valkeyrie implements (fully or partially) the Store interface.

Calls	Redis
Put	🟢️
Get	🟢️
Delete	🟢️
Exists	🟢️
Watch	🟢️
WatchTree	🟢️
NewLock (Lock/Unlock)	🟢️
List	🟢️
DeleteTree	🟢️
AtomicPut	🟢️
AtomicDelete	🟢️

Supported Versions

Redis versions >= 3.2.6. Key space notification needs to be enabled to have access to Watch and Lock methods.

Examples

package main

import (
	"context"
	"log"

	"github.com/kvtools/redis"
	"github.com/kvtools/valkeyrie"
)

func main() {
	ctx := context.Background()

	config := &redis.Config{
		Bucket: "example",
	}

	kv, err := valkeyrie.NewStore(ctx, redis.StoreName, []string{"localhost:8500"}, config)
	if err != nil {
		log.Fatal("Cannot create store")
	}

	key := "foo"

	err = kv.Put(ctx, key, []byte("bar"), nil)
	if err != nil {
		log.Fatalf("Error trying to put value at key: %v", key)
	}

	pair, err := kv.Get(ctx, key, nil)
	if err != nil {
		log.Fatalf("Error trying accessing value at key: %v", key)
	}

	log.Printf("value: %s", string(pair.Value))

	err = kv.Delete(ctx, key)
	if err != nil {
		log.Fatalf("Error trying to delete key %v", key)
	}
}

Documentation

Overview

Package redis contains the Redis store implementation.

Index

• Constants
• Variables
• type Codec
• type Config
• type JSONCodec
  • func (c JSONCodec) Decode(b []byte, kv *store.KVPair) error
  • func (c JSONCodec) Encode(kv *store.KVPair) (string, error)
• type RawCodec
  • func (c RawCodec) Decode(b []byte, kv *store.KVPair) error
  • func (c RawCodec) Encode(kv *store.KVPair) (string, error)
• type Store
  • func New(ctx context.Context, endpoints []string, options *Config) (*Store, error)
  • func NewWithCodec(ctx context.Context, endpoints []string, options *Config, codec Codec) (*Store, error)
  • func (r *Store) AtomicDelete(ctx context.Context, key string, previous *store.KVPair) (bool, error)
  • func (r *Store) AtomicPut(ctx context.Context, key string, value []byte, previous *store.KVPair, ...) (bool, *store.KVPair, error)
  • func (r *Store) Close() error
  • func (r *Store) Delete(ctx context.Context, key string) error
  • func (r *Store) DeleteTree(ctx context.Context, directory string) error
  • func (r *Store) Exists(ctx context.Context, key string, _ *store.ReadOptions) (bool, error)
  • func (r *Store) Get(ctx context.Context, key string, _ *store.ReadOptions) (*store.KVPair, error)
  • func (r *Store) List(ctx context.Context, directory string, _ *store.ReadOptions) ([]*store.KVPair, error)
  • func (r *Store) NewLock(_ context.Context, key string, opts *store.LockOptions) (store.Locker, error)
  • func (r *Store) Put(ctx context.Context, key string, value []byte, opts *store.WriteOptions) error
  • func (r *Store) Watch(ctx context.Context, key string, _ *store.ReadOptions) (<-chan *store.KVPair, error)
  • func (r *Store) WatchTree(ctx context.Context, directory string, _ *store.ReadOptions) (<-chan []*store.KVPair, error)

Constants

const StoreName = "redis"

StoreName the name of the store.

Variables

var (
	// ErrMultipleEndpointsUnsupported is thrown when there are
	// multiple endpoints specified for Redis.
	ErrMultipleEndpointsUnsupported = errors.New("redis: does not support multiple endpoints")

	// ErrAbortTryLock is thrown when a user stops trying to seek the lock
	// by sending a signal to the stop chan,
	// this is used to verify if the operation succeeded.
	ErrAbortTryLock = errors.New("redis: lock operation aborted")
)

Types

type Codec

type Codec interface {
	Encode(kv *store.KVPair) (string, error)
	Decode(b []byte, kv *store.KVPair) error
}

Codec KVPair persistence interface.

type Config

type Config struct {
	TLS      *tls.Config
	Username string
	Password string
	DB       int
}

Config the Redis configuration.

type JSONCodec

type JSONCodec struct{}

JSONCodec is a simple codec to read and write valkeyrie JSON object.

func (JSONCodec) Decode

func (c JSONCodec) Decode(b []byte, kv *store.KVPair) error

Decode a byte slice of valkeyrie JSON object to a KVPair.

func (JSONCodec) Encode

func (c JSONCodec) Encode(kv *store.KVPair) (string, error)

Encode a KVPair to a valkeyrie JSON object.

type RawCodec

type RawCodec struct{}

RawCodec is a simple codec to read and write string.

func (RawCodec) Decode

func (c RawCodec) Decode(b []byte, kv *store.KVPair) error

Decode a byte slice to a KVPair.

func (RawCodec) Encode

func (c RawCodec) Encode(kv *store.KVPair) (string, error)

Encode a KVPair to a string.

type Store

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

Store implements the store.Store interface.

func New

func New(ctx context.Context, endpoints []string, options *Config) (*Store, error)

New creates a new Redis client.

func NewWithCodec

func NewWithCodec(ctx context.Context, endpoints []string, options *Config, codec Codec) (*Store, error)

NewWithCodec creates a new Redis client with codec config.

func (*Store) AtomicDelete

func (r *Store) AtomicDelete(ctx context.Context, key string, previous *store.KVPair) (bool, error)

AtomicDelete is an atomic delete operation on a single value the value will be deleted if previous matched the one stored in db.

func (*Store) AtomicPut

func (r *Store) AtomicPut(ctx context.Context, key string, value []byte, previous *store.KVPair, opts *store.WriteOptions) (bool, *store.KVPair, error)

AtomicPut is an atomic CAS operation on a single value. Pass previous = nil to create a new key. We introduced script on this page, so atomicity is guaranteed.

func (*Store) Close

func (r *Store) Close() error

Close the store connection.

func (*Store) Delete

func (r *Store) Delete(ctx context.Context, key string) error

Delete the value at the specified key.

func (*Store) DeleteTree

func (r *Store) DeleteTree(ctx context.Context, directory string) error

DeleteTree deletes a range of keys under a given directory. glitch: we list all available keys first and then delete them all it costs two operations on redis, so is not atomicity.

func (*Store) Exists

func (r *Store) Exists(ctx context.Context, key string, _ *store.ReadOptions) (bool, error)

Exists verify if a Key exists in the store.

func (*Store) Get

func (r *Store) Get(ctx context.Context, key string, _ *store.ReadOptions) (*store.KVPair, error)

Get a value given its key.

func (*Store) List

func (r *Store) List(ctx context.Context, directory string, _ *store.ReadOptions) ([]*store.KVPair, error)

List the content of a given prefix.

func (*Store) NewLock

func (r *Store) NewLock(_ context.Context, key string, opts *store.LockOptions) (store.Locker, error)

NewLock creates a lock for a given key. The returned Locker is not held and must be acquired with `.Lock`. The Value is optional.

func (*Store) Put

func (r *Store) Put(ctx context.Context, key string, value []byte, opts *store.WriteOptions) error

Put a value at the specified key.

func (*Store) Watch

func (r *Store) Watch(ctx context.Context, key string, _ *store.ReadOptions) (<-chan *store.KVPair, error)

Watch for changes on a key. glitch: we use notified-then-retrieve to retrieve *store.KVPair. so the responses may sometimes inaccurate.

func (*Store) WatchTree

func (r *Store) WatchTree(ctx context.Context, directory string, _ *store.ReadOptions) (<-chan []*store.KVPair, error)

WatchTree watches for changes on child nodes under a given directory.