浅谈基于openresty(nginx+lua)开发轻量级,按流量控制的灰度模块（下）

  -- Copyright (C) www.bytearch.com (iyw)
    local config = require("gray.config")
    -- 按流量灰度
    local _M = {
        _VERSION = "0.0."
    }
    -- request count
    local req_count = 0;
    local uri_req_count_map = {}
    local function _getRequestUri()
        local uri = ngx.var.uri
        return uri
    end
    -- write api transmit to new api
    local function _isProxyNewMust()
        local proxy_new_uri_list = config['must_proxy_new_uri_list']
        if proxy_new_uri_list[_getRequestUri()] then
            return true
        end
        return false;
    end
    local function _checkWhiteReq()
        local headers = ngx.req.get_headers()
        local white_ip_list = config['white_ip_list']
        local ip = headers["X-REAL-IP"] or headers["X_FORWARDED_FOR"] or ngx.var.remote_addr or "0.0.0.0"
        for _, v in ipairs(white_ip_list) do
            if v == ip then
                return true
            end
        end
        return false
    end
    local function _getReqCnt()
        req_count = req_count + 1
        return req_count;
    end
    local function _getReqCountByKey(key)
        local req_count = uri_req_count_map[key]
        if req_count == nil then
            req_count = 0
        end
        uri_req_count_map[key] = req_count + 1
        return uri_req_count_map[key]
    end
    local function _getUpstreamByUriAndCount()
        local proxy_sys_level = config['proxy_sys_level']
        local old_upstream = config['old_upstream']
        local new_upstream = config['new_upstream']
        local proxy_percent = config['proxy_percent']
        -- system level
        if proxy_sys_level == 2 then
            return old_upstream
        elseif proxy_sys_level == 1 then
            return new_upstream
        else
            if _checkWhiteReq() == true then
                return new_upstream
            end
            -- write first
            if _isProxyNewMust() == true then
                return new_upstream
            end
            local uri = _getRequestUri()
            -- proxy cantain uri
            local proxy_uri_list = config['proxy_uri_list']
            if uri and proxy_uri_list[uri] then
                local count = _getReqCountByKey(uri)
                if (count % proxy_percent.base) < proxy_percent.new then
                    return new_upstream
                end
            end
            return old_upstream
        end
    end
    function _M.init()
        local upstream = _getUpstreamByUriAndCount();
        ngx.var.backend = upstream
    end
    return _M

server{
    listen 9001;
    server_name localhost;
    index index.html index.do;
    access_log logs/index_access.log;
    error_log  logs/index_error.log info;
    charset utf-8;
    default_type 'text/html';
    location ~ /write {
        content_by_lua '
            ngx.say("old write api")
        ';
    }
    location ~ /(.*){
        set $proxy_uri $1;
        content_by_lua '
            ngx.say("<h2> Old Api, uri:", ngx.var.proxy_uri , "</h2>")
        ';
    }
}

#此处配置新老系统地址
upstream proxy_old {
    server localhost:9001 max_fails=3 fail_timeout=2s;
    keepalive 32;
}
upstream proxy_new {
    server localhost:9002 max_fails=3 fail_timeout=2s;
    keepalive 32;
}
server{
    listen 9000;
    server_name localhost;
    index index.html index.do;
    access_log logs/index_access.log;
    error_log  logs/index_error.log info;
    charset utf-8;
    default_type 'text/html';
    ## 注意: lua_code_cache需要设置为on
    lua_code_cache on;
    location ~* /(.*) {
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $http_host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_http_version 1.1;
        set $backend "proxy_old";
        rewrite_by_lua_block  {
              local proxy = require("gray.proxy");
              if proxy then
                   proxy.init()
              end
        }
        proxy_pass http://$backend;
    }
}