https://github.com/kingluo/lua-resty-ffi-etcd

openresty etcd client library
https://github.com/kingluo/lua-resty-ffi-etcd

etcd-client etcdv3 golang luajit nginx openresty

Last synced: about 1 month ago
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openresty etcd client library

• Host: GitHub
• URL: https://github.com/kingluo/lua-resty-ffi-etcd
• Owner: kingluo
• License: bsd-3-clause
• Created: 2023-05-21T12:20:48.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-05-21T15:11:33.000Z (over 1 year ago)
• Last Synced: 2024-11-15T04:10:29.939Z (about 2 months ago)
• Topics: etcd-client, etcdv3, golang, luajit, nginx, openresty
• Language: Go
• Homepage:
• Size: 26.4 KB
• Stars: 4
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# lua-resty-ffi-etcd

The openresty etcd client library.

It encapsulates the etcd official [go client library](https://pkg.go.dev/go.etcd.io/etcd/client/v3).

## Background

If you access etcd directly using bare HTTP/GRPC, you will face the following problems:

* [smart load balancer](https://etcd.io/docs/v3.5/learning/design-client/) for multi-nodes etcd cluster

  * Sync cluster membership changes, e.g. replace a stale node

  * Full-featured node health check based on etcd client design

  * Conditional retry

* Compose low-level APIs to do some high-level stuff like authentication

* Lack of support for additional features like [grpc-proxy](https://etcd.io/docs/v3.5/op-guide/grpc_proxy/#client-endpoint-synchronization-and-name-resolution)

* Keep up-to-date with etcd official server code changes and fix bugs yourself

Since etcd has an brilliant and active official go client, why not encapsulate it so that we could reuse it in openresty?

[lua-resty-ffi](https://github.com/kingluo/lua-resty-ffi) provides an efficient and generic API to do hybrid programming

in openresty with mainstream languages (Go, Python, Java, Rust, Nodejs).

`lua-resty-ffi-etcd = lua-resty-ffi + go-etcd`

## Synopsis

```lua

local etcd = require("resty.ffi.etcd")

local inspect = require("inspect")

local client = etcd.new{

    endpoints = {

        "httpbin.local:2379",

    },

}

local watch = client:watch{

    key = "/apisix/",

    is_prefix = true,

}

local ok, res = watch:recv()

assert(ok, "watch:recv failed")

ngx.say(inspect(res))

```

## Demo

```bash

# install lua-resty-ffi

# https://github.com/kingluo/lua-resty-ffi#install-lua-resty-ffi-via-luarocks

# set `OR_SRC` to your openresty source path

luarocks config variables.OR_SRC /tmp/tmp.Z2UhJbO1Si/openresty-1.21.4.1

luarocks install lua-resty-ffi

cd /opt

git clone https://github.com/kingluo/lua-resty-ffi-etcd

cd /opt/lua-resty-ffi-etcd

make

cd /opt/lua-resty-ffi-etcd/demo

# run nginx

LD_LIBRARY_PATH=/opt/lua-resty-ffi-etcd:/usr/local/lib/lua/5.1 \

nginx -p $PWD -c nginx.conf

# in another terminal, run demo

curl localhost:20000/demo/watch

```

### Benchmark

![etcd_benchmark](etcd_benchmark.svg)

https://github.com/kingluo/etcd-benchmark

The overhead of encapsulation is approximately `20%`. Of course, there is improvement room.

### TODO

* [x] Watcher

* [ ] KV

* [ ] Lease