e5d4b47881
* Work around Hashing and tests * fixes * add TravisCI * fix lint * so slow * add badges * work on README * Improved tests and get rid of fnv (#3)
56 lines
No EOL
1.8 KiB
Markdown
56 lines
No EOL
1.8 KiB
Markdown
# Golang HRW implementation
|
|
|
|
[](https://travis-ci.org/im-kulikov/hrw)
|
|
[](https://codecov.io/gh/im-kulikov/hrw)
|
|
[](https://goreportcard.com/report/github.com/im-kulikov/hrw)
|
|
[](https://github.com/im-kulikov/hrw)
|
|
|
|
[Rendezvous or highest random weight](https://en.wikipedia.org/wiki/Rendezvous_hashing) (HRW) hashing is an algorithm that allows clients to achieve distributed agreement on a set of k options out of a possible set of n options. A typical application is when clients need to agree on which sites (or proxies) objects are assigned to. When k is 1, it subsumes the goals of consistent hashing, using an entirely different method.
|
|
|
|
## Install
|
|
|
|
`go get github.com/im-kulikov/hrw`
|
|
|
|
## Example
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
"github.com/im-kulikov/hrw"
|
|
)
|
|
|
|
func main() {
|
|
// given a set of servers
|
|
servers := []string{
|
|
"one.example.com",
|
|
"two.example.com",
|
|
"three.example.com",
|
|
"four.example.com",
|
|
"five.example.com",
|
|
"six.example.com",
|
|
}
|
|
|
|
// HRW can consistently select a uniformly-distributed set of servers for
|
|
// any given key
|
|
var (
|
|
key = []byte("/examples/object-key")
|
|
h = hrw.Hash(key)
|
|
)
|
|
|
|
hrw.SortSliceByValue(servers, h)
|
|
for id := range servers {
|
|
fmt.Printf("trying GET %s%s\n", servers[id], key)
|
|
}
|
|
|
|
// Output:
|
|
// trying GET four.example.com/examples/object-key
|
|
// trying GET three.example.com/examples/object-key
|
|
// trying GET one.example.com/examples/object-key
|
|
// trying GET two.example.com/examples/object-key
|
|
// trying GET six.example.com/examples/object-key
|
|
// trying GET five.example.com/examples/object-key
|
|
}
|
|
``` |