open files with ngx.location.capture and websockets

waster2008 · 2016-11-08T20:55:29+00:00

Hello! On Tue, Nov 8, 2016 at 3:17 AM, shanthu Venkatesan wrote: > Is there a plan to support HTTP/2 in Test::Nginx::Socket? Yes. > If so when can...

open files with ngx.location.capture and websockets

waster2008

Hello,

I'm trying to implement simple json file output with lua-resty-websocketmodule. Here is the example snippets of nginx and lua:


nginx ws-test.conf:
--------------------------------------------------------------------
server {
    listen 3001 so_keepalive=5s:5s:10 backlog=65535;
    server_name ws-test;
    send_timeout 10s;

    location / {
        access_log /var/log/nginx/ws-access.log;
        lua_socket_log_errors off;
        lua_check_client_abort on;
        content_by_lua_file /etc/nginx/lua/index.lua;
    }

    location /json {
       internal;
       root /var/www/;
    }
}
--------------------------------------------------------------------

index.lua:
--------------------------------------------------------------------
local S = {}

S = {
 	['test'] = '1.json'
}

local server = require "resty.websocket.server"
-- websocket server
local ws, err = server:new{
    timeout = 10000,
    max_payload_len = 65535,
}
if not ws then
    ngx.log(ngx.ERR, "failed to new websocket: ", err)
    return ngx.exit(444)
end

while true do
    local data, typ, err = ws:recv_frame()
    if ws.fatal then
        ngx.log(ngx.ERR, "failed to receive frame: ", err)
        return ngx.exit(444)
    end
    if not data then
        local bytes, err = ws:send_ping()
        if not bytes then
            ngx.log(ngx.ERR, "failed to send ping: ", err)
            return ngx.exit(444)
        end
    elseif typ == "close" then break
    elseif typ == "ping" then
        local bytes, err = ws:send_pong()
        if not bytes then
            ngx.log(ngx.ERR, "failed to send pong: ", err)
            return ngx.exit(444)
        end
    elseif typ == "pong" then
        ngx.log(ngx.INFO, "client ponged")
-- send corresponding station metadata
    elseif typ == "text" then
        if data and S[data] ~= nil then
            local res = ngx.location.capture("/json/"..S[data])
            if res then
                local bytes, err = ws:send_text(res.body)
                if not bytes then
                    ngx.log(ngx.ERR, "failed to send metadata: ", err)
                    return ngx.exit(444)
                end
            end
        end
    end
end
ws:send_close()
--------------------------------------------------------------------

It works well but there is one problem. Each time message "test" is sentthrough established websocke connection new file descriptor/var/www/json/1.json is added while old descriptors remain open in nginxworker. For example I test it with 'wscat --connect' and send "test"message 5 times in one long connection. Then I get the followingdescriptors in nginx worker:

nginx 12950 www-data 25r REG 252,1 203581396539 /var/www/xmlsource/json/3.jsonnginx 12950 www-data 28r REG 252,1 203581396539 /var/www/xmlsource/json/3.jsonnginx 12950 www-data 29r REG 252,1 203581396539 /var/www/xmlsource/json/3.jsonnginx 12950 www-data 30r REG 252,1 203581396539 /var/www/xmlsource/json/3.jsonnginx 12950 www-data 31r REG 252,1 203581396539 /var/www/xmlsource/json/3.json

I guess it happens because nginx connection still remains open (aswebsocket in "keep-alive" mode with 'while true' loop).

So the main question here is there a way to properly handle thissituation and do not produce so many open files?


Best regards, Andrey