lua-resty-ffi-etcd

README

lua-resty-ffi-etcd

The openresty etcd client library.

It encapsulates the etcd official go client library.

Background

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

• smart load balancer 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
• 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 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

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

# 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

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

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

TODO

• Watcher
• KV
• Lease

Documentation

Overview

Copyright (c) 2023, Jinhua Luo (kingluo) luajit.io@gmail.com All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.