failed to send frame: failed to send frame: operation now in progress about lua-resty-websocket

[agentzh]

@wuyachao BTW, you have the following line in your websocket server code:

    wb:set_timeout(1000)  -- change the network timeout to 1 second

It starts with 5 sec timeout but you change it to 1 sec inside the loop.

[agentzh]

@wuyachao Your example is not standalone, we do not even know how you initialize your wb object. I suggest you provide a standalone and minimal example that can easily run on others' machines and reproduce the problem.

It seems that neither operation now in progress nor the protocol wrong type for socket are error messages produced by OpenResty. Maybe there's a problem on your other side of the websocket wire?

[wuyachao]

@agentzh thanks for your reply. this is my demo.

local client = require "resty.websocket.client"

local wb, err = client:new()
local uri = "ws://127.0.0.1:3000/ws"
local ok, err = wb:connect(uri)
if not ok then
    ngx.say("failed to connect: " .. err)
    return
end
local i = 0
while true do
    ngx.say(i)
    local bytes, err = wb:send_text("ping mmm")
    ngx.say("send msg:", bytes)
    if not bytes then
        ngx.say("failed to send frame: ", err)
        return
    end
    local bytes, err = wb:send_ping()
    ngx.say("send ping:", bytes)
    if not bytes then
        ngx.say("failed to send frame: ", err)
        return
    end
    local bytes, err = wb:send_pong()
    ngx.say("send pong:", bytes)
    if not bytes then
        ngx.say("failed to send frame: ", err)
        return
    end

    local data, typ, err = wb:recv_frame()
    if not data then
        ngx.say("failed to receive the frame: ", err)
        return
    end
    ngx.say("received: ", data, " (", typ, "): ", err)
    i = i + 1
    ngx.sleep(2)
end

local bytes, err = wb:send_close()
if not bytes then
    ngx.say("failed to send frame: ", err)
    return
end

ngx.say("end")

the other side of websocket is https://gist.github.com/wuyachao/ea16adc974a53a51ea8fa98fb89ec2ac

[agentzh]

@wuyachao Can you make the server openresty as well? We do not want to debug issues in a Go server. That's not our concern.

[wuyachao]

@agentzh sorry. this is the code of server side. listen on port :8850

local server = require "resty.websocket.server"

local wb, err = server:new{
    timeout = 5000,  -- in milliseconds
    max_payload_len = 65535,
}
if not wb then
    ngx.log(ngx.ERR, "failed to new websocket: ", err)
    return ngx.exit(444)
end
while true do
    local data, typ, err = wb:recv_frame()

    if not data then
        ngx.log(ngx.ERR, "failed to receive a frame: ", err)
        return ngx.exit(444)
    end

    if typ == "close" then
        -- for typ "close", err contains the status code
        local code = err

        -- send a close frame back:

        local bytes, err = wb:send_close(1000, "enough, enough!")
        if not bytes then
            ngx.log(ngx.ERR, "failed to send the close frame: ", err)
            return
        end
        ngx.log(ngx.INFO, "closing with status code ", code, " and message ", data)
        return
    end

    if typ == "ping" then
        -- send a pong frame back:

        local bytes, err = wb:send_pong(data)
        if not bytes then
            ngx.log(ngx.ERR, "failed to send frame: ", err)
            return
        end
    elseif typ == "pong" then
        -- just discard the incoming pong frame

    else
        ngx.log(ngx.INFO, "received a frame of type ", typ, " and payload ", data)
    end

    wb:set_timeout(1000)  -- change the network timeout to 1 second

    local bytes, err = wb:send_text("Hello world")
    if not bytes then
        ngx.log(ngx.ERR, "failed to send a text frame: ", err)
        return ngx.exit(444)
    end
end

local bytes, err = wb:send_close(1000, "enough, enough!")
if not bytes then
    ngx.log(ngx.ERR, "failed to send the close frame: ", err)
    return
end

the client request it per second.

local client = require "resty.websocket.client"
--ngx.say(1111111)
--ngx.exit(200)
--while true do
--    ngx.say(111)
--    ngx.sleep(2000)
--end

local wb, err = client:new()
--local uri = "ws://127.0.0.1:3000/websocket"
local uri = "ws://127.0.0.1:8850"
local ok, err = wb:connect(uri)
if not ok then
    ngx.say("failed to connect: " .. err)
    return
end
local i = 0
while true do
    ngx.say(i)
    local bytes, err = wb:send_text("ping mmm")
    ngx.say("send msg:", bytes)
    if not bytes then
        ngx.say("failed to send frame: ", err)
        return
    end
    local bytes, err = wb:send_ping()
    ngx.say("send ping:", bytes)
    if not bytes then
        ngx.say("failed to send frame: ", err)
        return
    end
    --    ngx.say(i)
    --    ngx.sleep(2000)
    local bytes, err = wb:send_pong()
    ngx.say("send pong:", bytes)
    if not bytes then
        ngx.say("failed to send frame: ", err)
        return
    end

    local data, typ, err = wb:recv_frame()
    if not data then
        ngx.say("failed to receive the frame: ", err)
        return
    end
    ngx.say("received: ", data, " (", typ, "): ", err)
    i = i + 1
    ngx.sleep(1)
end

local bytes, err = wb:send_close()
if not bytes then
    ngx.say("failed to send frame: ", err)
    return
end

---

curl localhost:8888:

0
send msg:14
send ping:6
send pong:6
received: Hello world (text): nil
1
send msg:14
send ping:6
send pong:6
received:  (pong): nil
2
send msg:nil
failed to send frame: failed to send frame: operation now in progress

the server error message:

2017/12/13 11:25:12 [error] 31460#0: *5 lua tcp socket read timed out, client: 127.0.0.1, server: , request: "GET / HTTP/1.1", host: "127.0.0.1:8850"
2017/12/13 11:25:12 [error] 31460#0: *5 [lua] main.lua:16: failed to receive a frame: failed to receive the first 2 bytes: timeout, client: 127.0.0.1, server: , request: "GET / HTTP/1.1", host: "127.0.0.1:8850"

but the websocket server timeout is 5 second. I request it per second.

[agentzh]

@wuyachao Well, the problem is that your websocket server should handle reading timeout errors gracefully instead of terminating the connection with ngx.exit(444). I can see that the code example in README is oversimplified here and it seems that you simply copy the code right over.

Basically you client sends the data every 2 seconds while your server sets the timeout threshold to 1 second, which will surely lead to the (nonfatal) reading timeout errors on your server side.

Another thing is that you need to call ngx.flush(true) on your client side so that you can see the output sooner.

I've updated your code example accordingly and it works fine on my side:

location /ws {
    content_by_lua_block {
        local server = require "resty.websocket.server"

        local wb, err = server:new{
            timeout = 5000,  -- in milliseconds
            max_payload_len = 65535,
        }
        if not wb then
            ngx.log(ngx.ERR, "failed to new websocket: ", err)
            return ngx.exit(444)
        end
        while true do
            local data, typ, err = wb:recv_frame()

            if not data then
                if not string.find(err, "timeout", 1, true) then
                    ngx.log(ngx.ERR, "failed to receive a frame: ", err)
                    return ngx.exit(444)
                end
            end

            if typ == "close" then
                -- for typ "close", err contains the status code
                local code = err

                -- send a close frame back:

                local bytes, err = wb:send_close(1000, "enough, enough!")
                if not bytes then
                    ngx.log(ngx.ERR, "failed to send the close frame: ", err)
                    return
                end
                ngx.log(ngx.INFO, "closing with status code ", code, " and message ", data)
                return
            end

            if typ == "ping" then
                -- send a pong frame back:

                local bytes, err = wb:send_pong(data)
                if not bytes then
                    ngx.log(ngx.ERR, "failed to send frame: ", err)
                    return
                end
            elseif typ == "pong" then
                -- just discard the incoming pong frame

            else
                ngx.log(ngx.INFO, "server received a frame of type ", typ, " and payload ", data)
            end

            -- wb:set_timeout(1000)  -- change the network timeout to 1 second

            local bytes, err = wb:send_text("Hello world")
            if not bytes then
                ngx.log(ngx.ERR, "failed to send a text frame: ", err)
                return ngx.exit(444)
            end
        end

        local bytes, err = wb:send_close(1000, "enough, enough!")
        if not bytes then
            ngx.log(ngx.ERR, "failed to send the close frame: ", err)
            return
        end
    }
}

location /client {
    content_by_lua_block {
        local client = require "resty.websocket.client"

        local wb, err = client:new()
        local uri = "ws://127.0.0.1:" .. ngx.var.server_port .. "/ws"
        local ok, err = wb:connect(uri)
        if not ok then
            ngx.say("failed to connect: " .. err)
            return
        end
        local i = 0
        while true do
            ngx.say(i)
            local bytes, err = wb:send_text("ping mmm")
            ngx.say("send msg:", bytes)
            if not bytes then
                ngx.say("failed to send frame: ", err)
                return
            end
            local bytes, err = wb:send_ping()
            ngx.say("send ping:", bytes)
            if not bytes then
                ngx.say("failed to send frame: ", err)
                return
            end
            local bytes, err = wb:send_pong()
            ngx.say("send pong:", bytes)
            if not bytes then
                ngx.say("failed to send frame: ", err)
                return
            end

            local data, typ, err = wb:recv_frame()
            if not data then
                ngx.say("failed to receive the frame: ", err)
                return
            end
            ngx.say("received: ", data, " (", typ, "): ", err)
            i = i + 1
            ngx.sleep(2)

            ngx.flush(true)
        end

        local bytes, err = wb:send_close()
        if not bytes then
            ngx.say("failed to send frame: ", err)
            return
        end

        ngx.say("end")
    }
}

And curl works:

$ curl localhost:1984/client
0
send msg:14
send ping:6
send pong:6
received: Hello world (text): nil
1
send msg:14
send ping:6
send pong:6
received:  (pong): nil
2
send msg:14
send ping:6
send pong:6
received: Hello world (text): nil
3
send msg:14
send ping:6
send pong:6
received: Hello world (text): nil
4
send msg:14
send ping:6
send pong:6
received: Hello world (text): nil
5
send msg:14
send ping:6
send pong:6
received:  (pong): nil
6
...

It emits a few lines of output evey 2 seconds and it will just go on and on forever since you use an infinite loop in both the client side and the server side.

[agentzh]

@wuyachao I've updated the code example in the README doc.

[wuyachao]

@agentzh thank you very much!