lua-resty-ffi provides a general and efficient interface, allowing you to use Go, Python, Java and Rust to directly develop the functions you want for OpenResty/Nginx.

As we all know, the lua and C used by OpenResty have a weak ecology, and many rebuilt wheels lack maintenance, so that it is difficult for a smart woman to cook without rice when interoperating with the peripheral ecosystem.

feature:

• Non-blocking, run as a coroutine
• Simple and extensible interface that supports any language that conforms to the C ABI
• Once and for all, no need to write any C or Lua modules to develop new functions
• High performance, faster than unix domain socket
• Universal java, python loader
• Use any message serialization format you like

The simplest example:

Use golang to develop an echo function.

Create a file: ​echo.go

package main

/*
#cgo LDFLAGS: -shared
#include <string.h>
void* ngx_http_lua_ffi_task_poll(void *p);
char* ngx_http_lua_ffi_get_req(void *tsk, int *len);
void ngx_http_lua_ffi_respond(void *tsk, int rc, char* rsp, int rsp_len);
*/
import "C"
import (
	"log"
	"unsafe"
)

//export libffi_init
func libffi_init(cfg_cstr *C.char, tq unsafe.Pointer) C.int {
	log.Println("start go echo runtime")
	go func() {
		for {
			task := C.ngx_http_lua_ffi_task_poll(tq)
			if task == nil {
				break
			}
			var rlen C.int
			r := C.ngx_http_lua_ffi_get_req(task, &rlen)
			res := C.malloc(C.ulong(rlen))
			C.memcpy(res, unsafe.Pointer(r), C.ulong(rlen))
			C.ngx_http_lua_ffi_respond(task, 0, (*C.char)(res), rlen)
		}
		log.Println("exit go echo runtime")
	}()
	return 0
}

func main() {}

Create a file: nginx.conf

daemon off;
error_log /dev/stderr info;
worker_processes auto;
env LD_LIBRARY_PATH;

events {}

http {
    server {
        listen 20000;

        location /echo {
            content_by_lua_block {
                local demo = ngx.load_ffi("ffi_go_echo")
                local ok, res = demo:echo("foobar")
                assert(ok)
                assert(res == "foobar")

                demo:__unload()
                ok, res = demo:echo("foobar")
                assert(not ok)
                ngx.log(ngx.ERR, res)

                ngx.say("ok")
            }
        }
    }
}

run:

​go build -buildmode=c-shared -o libffi_go_echo.so echo.go
LD_LIBRARY_PATH=$(PWD) $(NGINX_BIN) -p $(PWD) -c nginx.conf
curl localhost:20000/echo