consistent

Documentation

Index

• Variables
• type Consistent
  • func NewConsistentHash(opts ...Option) *Consistent
  • func (c *Consistent) Add(host string)
  • func (c *Consistent) Done(host string)
  • func (c *Consistent) Get(key string) (string, error)
  • func (c *Consistent) GetHash(hashKey uint32) (string, error)
  • func (c *Consistent) GetLeast(key string) (string, error)
  • func (c *Consistent) GetLoads() map[string]int64
  • func (c *Consistent) GetN(name string, n int) ([]string, error)
  • func (c *Consistent) GetTwo(name string) (string, string, error)
  • func (c *Consistent) Hash(key string) uint32
  • func (c *Consistent) Hosts() []string
  • func (c *Consistent) Inc(host string)
  • func (c *Consistent) MaxLoad() int64
  • func (c *Consistent) Members() []string
  • func (c *Consistent) Remove(host string) bool
  • func (c *Consistent) Set(elts []string)
  • func (c *Consistent) SetHashFunc(f HashFunc)
  • func (c *Consistent) UpdateLoad(host string, load int64)
• type HashFunc
• type Host
• type Option
  • func WithHashFunc(hash HashFunc) Option
  • func WithMaxVnodeNum(maxVnodeNum int) Option
  • func WithReplicaNum(replicaNum int) Option
• type Options

Variables

var ErrNoHosts = errors.New("no hosts added")

Types

type Consistent

type Consistent struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

func NewConsistentHash

func NewConsistentHash(opts ...Option) *Consistent

func (*Consistent) Add

func (c *Consistent) Add(host string)

func (*Consistent) Done

func (c *Consistent) Done(host string)

Done Decrements the load of host by 1 should only be used with if you obtained a host with GetLeast

func (*Consistent) Get

func (c *Consistent) Get(key string) (string, error)

Get It returns ErrNoHosts if the ring has no hosts in it

func (*Consistent) GetHash

func (c *Consistent) GetHash(hashKey uint32) (string, error)

GetHash It returns ErrNoHosts if the ring has no hosts in it

func (*Consistent) GetLeast

func (c *Consistent) GetLeast(key string) (string, error)

GetLeast It uses Consistent Hashing With Bounded loads https://research.googleblog.com/2017/04/consistent-hashing-with-bounded-loads.html to pick the least loaded host that can serve the key It returns ErrNoHosts if the ring has no hosts in it.

func (*Consistent) GetLoads

func (c *Consistent) GetLoads() map[string]int64

GetLoads Returns the loads of all the hosts

func (*Consistent) GetN

func (c *Consistent) GetN(name string, n int) ([]string, error)

GetN returns the N closest distinct elements to the name input in the circle

func (*Consistent) GetTwo

func (c *Consistent) GetTwo(name string) (string, string, error)

GetTwo returns the two closest distinct elements to the name input in the circle

func (*Consistent) Hash

func (c *Consistent) Hash(key string) uint32

func (*Consistent) Hosts

func (c *Consistent) Hosts() []string

Hosts Return the list of hosts in the ring

func (*Consistent) Inc

func (c *Consistent) Inc(host string)

Inc Increments the load of host by 1 should only be used with if you obtained a host with GetLeast

func (*Consistent) MaxLoad

func (c *Consistent) MaxLoad() int64

MaxLoad Returns the maximum load of the single host which is: (total_load/number_of_hosts)*1.25 total_load = is the total number of active requests served by hosts for more info: https://research.googleblog.com/2017/04/consistent-hashing-with-bounded-loads.html

func (*Consistent) Members

func (c *Consistent) Members() []string

func (*Consistent) Remove

func (c *Consistent) Remove(host string) bool

Remove Deletes host from the ring

func (*Consistent) Set

func (c *Consistent) Set(elts []string)

Set sets all the elements in the hash. If there are existing elements not present in elts, they will be removed.

func (*Consistent) SetHashFunc

func (c *Consistent) SetHashFunc(f HashFunc)

func (*Consistent) UpdateLoad

func (c *Consistent) UpdateLoad(host string, load int64)

UpdateLoad Sets the load of `host` to the given `load`

type HashFunc

type HashFunc func([]byte) uint64

type Host

type Host struct {
	Name string
	Load int64
}

type Option

type Option func(option *Options)

func WithHashFunc

func WithHashFunc(hash HashFunc) Option

func WithMaxVnodeNum

func WithMaxVnodeNum(maxVnodeNum int) Option

func WithReplicaNum

func WithReplicaNum(replicaNum int) Option

type Options

type Options struct {
	HashFunc    HashFunc
	ReplicaNum  int
	MaxVnodeNum int
}