Documentation
¶
Index ¶
- Constants
- func StableHash(data []byte) uint64
- type ConsistentHash
- func (ch *ConsistentHash) AddBuckets(newBuckets ...string) (ok bool)
- func (ch *ConsistentHash) Assignment(item string) (bucket string)
- func (ch *ConsistentHash) Assignments(items ...string) map[string][]string
- func (ch *ConsistentHash) Buckets() (buckets []string)
- func (ch *ConsistentHash) HashFunctionOrDefault() HashFunction
- func (ch *ConsistentHash) IsAssigned(bucket, item string) (ok bool)
- func (ch *ConsistentHash) MarshalJSON() ([]byte, error)
- func (ch *ConsistentHash) RemoveBucket(toRemove string) (ok bool)
- func (ch *ConsistentHash) ReplicasOrDefault() int
- func (ch *ConsistentHash) String() string
- type HashFunction
- type HashedBucket
Constants ¶
const (
// DefaultReplicas is the default number of bucket virtual replicas.
DefaultReplicas = 16
)
Variables ¶
This section is empty.
Functions ¶
func StableHash ¶
StableHash implements the default hash function with a stable crc64 table checksum.
Types ¶
type ConsistentHash ¶
type ConsistentHash struct {
Replicas int
HashFunction HashFunction
// contains filtered or unexported fields
}
ConsistentHash creates hashed assignments for each bucket.
func (*ConsistentHash) AddBuckets ¶
func (ch *ConsistentHash) AddBuckets(newBuckets ...string) (ok bool)
AddBuckets adds a list of buckets to the consistent hash, and returns a boolean indiciating if _any_ buckets were added.
If any of the new buckets do not exist on the hash ring the new bucket will be inserted `ReplicasOrDefault` number of times into the internal hashring.
If any of the new buckets already exist on the hash ring no action is taken for that bucket.
Calling `AddBuckets` is safe to do concurrently and acquires a write lock on the consistent hash reference.
func (*ConsistentHash) Assignment ¶
func (ch *ConsistentHash) Assignment(item string) (bucket string)
Assignment returns the bucket assignment for a given item.
Calling `Assignment` is safe to do concurrently and acquires a read lock on the consistent hash reference.
func (*ConsistentHash) Assignments ¶
func (ch *ConsistentHash) Assignments(items ...string) map[string][]string
Assignments returns the assignments for a given list of items organized by the name of the bucket, and an array of the assigned items.
Calling `Assignments` is safe to do concurrently and acquires a read lock on the consistent hash reference.
func (*ConsistentHash) Buckets ¶
func (ch *ConsistentHash) Buckets() (buckets []string)
Buckets returns the buckets.
Calling `Buckets` is safe to do concurrently and acquires a read lock on the consistent hash reference.
func (*ConsistentHash) HashFunctionOrDefault ¶
func (ch *ConsistentHash) HashFunctionOrDefault() HashFunction
HashFunctionOrDefault returns the provided hash function or a default.
func (*ConsistentHash) IsAssigned ¶
func (ch *ConsistentHash) IsAssigned(bucket, item string) (ok bool)
IsAssigned returns if a given bucket is assigned a given item.
Calling `IsAssigned` is safe to do concurrently and acquires a read lock on the consistent hash reference.
func (*ConsistentHash) MarshalJSON ¶
func (ch *ConsistentHash) MarshalJSON() ([]byte, error)
MarshalJSON marshals the consistent hash as json.
The form of the returned json is the underlying []HashedBucket and there is no corresponding `UnmarshalJSON` because it is uncertain on the other end what the hashfunction is because functions can't be json serialized.
You should use MarshalJSON for communicating information for debugging purposes only.
Calling `MarshalJSON` is safe to do concurrently and acquires a read lock on the consistent hash reference.
func (*ConsistentHash) RemoveBucket ¶
func (ch *ConsistentHash) RemoveBucket(toRemove string) (ok bool)
RemoveBucket removes a bucket from the consistent hash, and returns a boolean indicating if the provided bucket was found.
If the bucket exists on the hash ring, the bucket and its replicas are removed.
If the bucket does not exist on the ring, no action is taken.
Calling `RemoveBucket` is safe to do concurrently and acquires a write lock on the consistent hash reference.
func (*ConsistentHash) ReplicasOrDefault ¶
func (ch *ConsistentHash) ReplicasOrDefault() int
ReplicasOrDefault is the default number of bucket virtual replicas.
func (*ConsistentHash) String ¶
func (ch *ConsistentHash) String() string
String returns a string form of the hash for debugging purposes.
Calling `String` is safe to do concurrently and acquires a read lock on the consistent hash reference.
type HashFunction ¶
HashFunction is a function that can be used to hash items.
type HashedBucket ¶
type HashedBucket struct {
Hashcode uint64 `json:"hashcode"`
Bucket string `json:"bucket"`
Replica int `json:"replica"`
}
HashedBucket is a bucket in the hashring that holds the hashcode, the bucket name (as Bucket) and the virtual replica index.
Source Files