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https://github.com/ruoshan/lua-resty-jump-consistent-hash
consistent hash for openresty
https://github.com/ruoshan/lua-resty-jump-consistent-hash
consistent-hashing luajit openresty
Last synced: 3 months ago
JSON representation
consistent hash for openresty
- Host: GitHub
- URL: https://github.com/ruoshan/lua-resty-jump-consistent-hash
- Owner: ruoshan
- License: mit
- Created: 2016-03-17T05:07:17.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2019-01-15T06:48:04.000Z (almost 6 years ago)
- Last Synced: 2024-02-14T11:49:58.926Z (9 months ago)
- Topics: consistent-hashing, luajit, openresty
- Language: Perl
- Homepage:
- Size: 23.4 KB
- Stars: 25
- Watchers: 5
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-resty - lua-resty-jump-consistent-hash
README
## Jump Consisten Hash for luajit
A simple implementation of [this paper](http://arxiv.org/pdf/1406.2294.pdf).
## Features
- small memory footprint and fast
- consistence is maintained through servers' updating
## Installation
```
make
make PREFIX=/usr/local/openresty install
```
## Usage
* you can use the basic jchash module to do consistent-hash
```
local jchash = require "resty.chash.jchash"
local buckets = 8
local id = jchash.hash_short_str("random key", buckets)
```
* or you can use the wrapping module `resty.chash.server` to consistent-hash a list of servers
```
local jchash_server = require "resty.chash.server"
local my_servers = {
{ "127.0.0.1", 80, 1}, -- {addr, port, weight} weight can be left out if it's 1
{ "127.0.0.2", 80 },
{ "127.0.0.3", 80 }
}
local cs, err = jchash_server.new(my_servers)
local uri = ngx.var.uri
local svr = cs:lookup(uri)
local addr = svr[1]
local port = svr[2]
-- now you can use the ngx.balancer to do some consistent LB
-- you can even update the servers list, and still maintain the consistence, eg.
local my_new_servers = {
{ "127.0.0.2", 80 },
{ "127.0.0.3", 80 },
{ "127.0.0.4", 80 }
}
cs:update_servers(my_new_servers)
svr = cs:lookup(uri) -- if the server was 127.0.0.2, then it stays the same,
-- as we only update the 127.0.0.4.
-- what's more, consistence is maintained even the number of servers changes! eg.
local my_less_servers = {
{ "127.0.0.2", 80 },
{ "127.0.0.3", 80 }
}
cs:update_servers(my_less_servers)
svr = cs:lookup(uri) -- if the server was 127.0.0.2, then it stays the same,
-- if the server was 127.0.0.4, then it has 50% chance to be
-- 127.0.0.2 or 127.0.0.3
cs:update_servers(my_new_servers)
svr = cs:lookup(uri) -- if the server was 127.0.0.2, then it has 66% chance to stay the same
```
## Todo
- ~~weight for the servers list~~ [done]
- ~~Test::Nginx~~ [done]
## Test
```
make test
```