resty_functions/prod/upload/upload.lua

local upload = require "resty.upload"
local uuid      = require "resty.jit-uuid"
local cjson     = require "cjson"

local chunk_size = 4096
local form = upload:new(chunk_size)
uuid.seed()

local task_server = ngx.var.task_server
local file_dir = ngx.var.tmp_file_dir
local file
local file_name
local files = {}

while true do
    local typ, res, err = form:read()

    if not typ then
        ngx.say("failed to read: ", err)
        return
    end

    if typ == "header" then

        --"Content-Disposition","form-data; name=\"files[]\"; filename=\"Song-of-joy.png\""
        --"Content-Type","image\/png"
        local key = res[1]
        local val = res[2]
        if key == "Content-Type" then
            local ext = ngx.re.match(val, [[(\w+)\/(\w+)]], "jo")[2]
            file_name = string.format("%s/%s.%s", file_dir, uuid(), ext)
        end

        if file_name then
            file = io.open(file_name, "w+")
            if not file then
                ngx.say("failed to open file ", file_name)
                return
            end
        end

    elseif typ == "body" then
        if file then
            file:write(res)
            -- sha1:update(res)
        end

    elseif typ == "part_end" then
        if file then
            file:close()
            table.insert(files, file_name)
        end
        file = nil
    elseif typ == "eof" then
        local http = require "resty.http"
        local httpc = http.new()
        local remote_url = string.format("%s/api/v1/ts/create_task", task_server)
        local res, err = httpc:request_uri(
                remote_url,
                {
                    method = "POST",
                    headers = {
                      host = "ngx"
                    },
                    body = {
                        cjson.encode({task_type = 1, data = files})
                    },
                }
        )
        if 201 ~= res.status then
            ngx.log(ngx.ERR, "create task failed", err)
            ngx.say(err)
            ngx.exit(res.status)
        end
        ngx.say(res.body)
        break
    else
        -- do nothing
    end
end