store

Documentation

Index

• Variables
• func CheckKeyword(key string) bool
• func GenKeys(num int, depth int) []string
• type EtcdStats
• type ListNode
• type Node
• type Response
• type Store
  • func CreateStore(max int) *Store
  • func (s *Store) AddWatcher(prefix string, watcher *Watcher, sinceIndex uint64) error
  • func (s *Store) Delete(key string, index uint64) ([]byte, error)
  • func (s *Store) Get(key string) ([]byte, error)
  • func (s *Store) RawGet(key string) ([]*Response, error)
  • func (s *Store) Recovery(state []byte) error
  • func (s *Store) Save() ([]byte, error)
  • func (s *Store) Set(key string, value string, expireTime time.Time, index uint64) ([]byte, error)
  • func (s *Store) SetMessager(messager chan<- string)
  • func (s *Store) Stats() []byte
  • func (s *Store) TestAndSet(key string, prevValue string, value string, expireTime time.Time, index uint64) ([]byte, error)
  • func (s *Store) TotalWrites() uint64
• type Watcher
  • func NewWatcher() *Watcher
• type WatcherHub

Variables

var PERMANENT = time.Unix(0, 0)

Functions

func CheckKeyword

func CheckKeyword(key string) bool

CheckKeyword will check if the key contains the keyword. For now, we only check for prefix.

func GenKeys

func GenKeys(num int, depth int) []string

GenKeys randomly generate num of keys with max depth

Types

type EtcdStats

type EtcdStats struct {
	// Number of get requests
	Gets uint64 `json:"gets"`

	// Number of sets requests
	Sets uint64 `json:"sets"`

	// Number of delete requests
	Deletes uint64 `json:"deletes"`

	// Number of testAndSet requests
	TestAndSets uint64 `json:"testAndSets"`
}

type ListNode

type ListNode struct {
	Key   string
	Value string
	Type  string
}

A listNode represent the simplest Key-Value pair with its type It is only used when do list opeartion We want to have a file system like store, thus we distingush "file" and "directory"

type Node

type Node struct {
	// The string value of the node
	Value string `json:"value"`

	// If the node is a permanent one the ExprieTime will be Unix(0,0)
	// Otherwise after the expireTime, the node will be deleted
	ExpireTime time.Time `json:"expireTime"`
	// contains filtered or unexported fields
}

A Node represents a Value in the Key-Value pair in the store It has its value, expire time and a channel used to update the expire time (since we do countdown in a go routine, we need to communicate with it via channel)

type Response

type Response struct {
	Action    string `json:"action"`
	Key       string `json:"key"`
	Dir       bool   `json:"dir,omitempty"`
	PrevValue string `json:"prevValue,omitempty"`
	Value     string `json:"value,omitempty"`

	// If the key did not exist before the action,
	// this field should be set to true
	NewKey bool `json:"newKey,omitempty"`

	Expiration *time.Time `json:"expiration,omitempty"`

	// Time to live in second
	TTL int64 `json:"ttl,omitempty"`

	// The command index of the raft machine when the command is executed
	Index uint64 `json:"index"`
}

The response from the store to the user who issue a command

type Store

type Store struct {

	// key-value store structure
	Tree *tree

	// A map to keep the recent response to the clients
	ResponseMap map[string]*Response

	// The max number of the recent responses we can record
	ResponseMaxSize int

	// The current number of the recent responses we have recorded
	ResponseCurrSize uint

	// The index of the first recent responses we have
	ResponseStartIndex uint64

	// Current index of the raft machine
	Index uint64

	// Basic statistics information of etcd storage
	BasicStats EtcdStats
	// contains filtered or unexported fields
}

The main struct of the Key-Value store

func CreateStore

func CreateStore(max int) *Store

Create a new stroe Arguement max is the max number of response we want to record

func (*Store) AddWatcher

func (s *Store) AddWatcher(prefix string, watcher *Watcher, sinceIndex uint64) error

Add a channel to the watchHub. The watchHub will send response to the channel when any key under the prefix changes [since the sinceIndex if given]

func (*Store) Delete

func (s *Store) Delete(key string, index uint64) ([]byte, error)

func (*Store) Get

func (s *Store) Get(key string) ([]byte, error)

Get all the items under key If key is a file return the file If key is a directory reuturn an array of files

func (*Store) RawGet

func (s *Store) RawGet(key string) ([]*Response, error)

func (*Store) Recovery

func (s *Store) Recovery(state []byte) error

Recovery the state of the stroage system from a previous state

func (*Store) Save

func (s *Store) Save() ([]byte, error)

Save the current state of the storage system

func (*Store) Set

func (s *Store) Set(key string, value string, expireTime time.Time, index uint64) ([]byte, error)

func (*Store) SetMessager

func (s *Store) SetMessager(messager chan<- string)

Set the messager of the store

func (*Store) Stats

func (s *Store) Stats() []byte

Stats returns the basic statistics information of etcd storage since its recent start

func (*Store) TestAndSet

func (s *Store) TestAndSet(key string, prevValue string, value string, expireTime time.Time, index uint64) ([]byte, error)

Set the value of the key to the value if the given prevValue is equal to the value of the key

func (*Store) TotalWrites

func (s *Store) TotalWrites() uint64

TotalWrites returns the total write operations It helps with snapshot

type Watcher

type Watcher struct {
	C chan *Response
}

Currently watcher only contains a response channel

func NewWatcher

func NewWatcher() *Watcher

Create a new watcher

type WatcherHub

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

WatcherHub is where the client register its watcher