tcp连接的setkeepalive方法返回error

haifeng414

我直接用https://github.com/chronolaw/openresty_dev这个仓库的代码测试keepalive，运行curl 127.1:81/cosocket -d "12|34|"命令，得到的输出是：

12,
34,
failed to read data: closed
sock usedtimes = 0
receive from backend. len: 16 data: hellohellohello

usedtimes的值始终是0，setkeepalive方法执行失败，我把err打印出来，显示的是invalid connection，我在ngx_stream_lua_socket_tcp.c这个文件里看到这个错误信息的判断如下：

if (c->read->eof
        || c->read->error
        || c->read->timedout
        || c->write->error
        || c->write->timedout)
    {
        lua_pushnil(L);
        lua_pushliteral(L, "invalid connection");
        return 2;
    }

为了知道是哪个条件导致的失败，我这样修改源码：

if (c->read->eof)
    {
        lua_pushnil(L);
        lua_pushliteral(L, "read eof invalid connection");
        return 2;
    }

    if (c->read->error)
    {
        lua_pushnil(L);
        lua_pushliteral(L, "read error invalid connection");
        return 2;
    }

    if (c->read->timedout)
    {
        lua_pushnil(L);
        lua_pushliteral(L, "read timeout invalid connection");
        return 2;
    }

    if (c->write->error)
    {
        lua_pushnil(L);
        lua_pushliteral(L, "write error invalid connection");
        return 2;
    }

    if (c->write->timedout)
    {
        lua_pushnil(L);
        lua_pushliteral(L, "write timeout invalid connection");
        return 2;
    }

最后编译重现问题，日志显示错误信息为：read eof invalid connection。
请问这个问题如何避免，是缺少什么配置吗。

doujiang24

建议你使用标准的 OpenResty 来测试，以及贴最小化可以验证的代码，要不对于理解你这个问题，还得做不少了解的功课

haifeng414

doujiang24
感谢回复，下面是我的demo
nginx.conf文件

worker_processes 1;

events {
    worker_connections 512;
}

http {
    server {
        listen 81;
        server_name *.*;

        location ~ ^/(\w+) {
            content_by_lua_file service/backend/$1.lua;
        }

        location / {
            content_by_lua_block {
                ngx.say("hello openresty backend")
            }
        }
    }
}

stream {
    server {
        listen 900;
        content_by_lua_file service/stream/cosocket.lua;
    }
}

service/backend/cosocket.lua文件

local sock = ngx.socket.tcp()
sock:settimeout(3000)

local ok, err = sock:connect("127.0.0.1", 900)
if not ok then
    ngx.say("failed to connect to backend: ", err)
    return
end

local count, err = sock:getreusedtimes()
ngx.say("sock usedtimes = ", count)

local data, err = sock:receive("*a")
if not data or err then
    ngx.log(ngx.ERR, "recieve data from backend failed: ", err)
    return
end

ngx.say("receive from backend: ", data)
ngx.log(ngx.ERR, "test in client")

local ok, err = sock:setkeepalive()
if err then
    ngx.log(ngx.ERR, "setkeepalive failed: ", err)
elseif ok then
    ngx.log(ngx.ERR, "setkeepalive success")
end

service/stream/cosocket.lua文件

local sock = ngx.req.socket()

local bytes, err = sock:send("test")
if err then
    ngx.say("failed to send data to client: ", err)
    return
end
ngx.log(ngx.ERR, "test in server")

我运行curl 127.1:81/cosocket命令得到的输出是：

sock usedtimes = 0
receive from backend: test

我在service/backend/cosocket.lua文件中执行了setkeepalive方法，期望的是多次执行curl
curl命令usedtimes的值会相应的增加，但是结果是始终为0，我查看日志，setkeepalive方法返回的error
error信息是invalid connection，不明白是什么导致的这个错误。

haifeng414

感谢回复，下面是我的demo
nginx.conf文件

worker_processes 1;

events {
    worker_connections 512;
}

http {
    server {
        listen 81;
        server_name *.*;

        location ~ ^/(\w+) {
            content_by_lua_file service/backend/$1.lua;
        }

        location / {
            content_by_lua_block {
                ngx.say("hello openresty backend")
            }
        }
    }
}

stream {
    server {
        listen 900;
        content_by_lua_file service/stream/cosocket.lua;
    }
}

service/backend/cosocket.lua文件

local sock = ngx.socket.tcp()
sock:settimeout(3000)

local ok, err = sock:connect("127.0.0.1", 900)
if not ok then
    ngx.say("failed to connect to backend: ", err)
    return
end

local count, err = sock:getreusedtimes()
ngx.say("sock usedtimes = ", count)

local data, err = sock:receive("*a")
if not data or err then
    ngx.log(ngx.ERR, "recieve data from backend failed: ", err)
    return
end

ngx.say("receive from backend: ", data)
ngx.log(ngx.ERR, "test in client")

local ok, err = sock:setkeepalive()
if err then
    ngx.log(ngx.ERR, "setkeepalive failed: ", err)
elseif ok then
    ngx.log(ngx.ERR, "setkeepalive success")
end

service/stream/cosocket.lua文件

local sock = ngx.req.socket()

local bytes, err = sock:send("test")
if err then
    ngx.say("failed to send data to client: ", err)
    return
end
ngx.log(ngx.ERR, "test in server")

我运行curl 127.1:81/cosocket命令得到的输出是：

sock usedtimes = 0
receive from backend: test