Kong[nginx]-12 插件開發(fā)實(shí)踐(redis)

0x00 前言

上一篇我們聊到自定義插件的用途, 這里我們實(shí)踐一下: 把API網(wǎng)關(guān)做為接口服務(wù)提供者來使用.
(這種用法, 雖然有點(diǎn)不務(wù)正業(yè), 不過至少給后端開發(fā)者多提供了一些腦洞. 至于實(shí)際的使用場景,請小伙伴們自由發(fā)揮, 可以在評(píng)論區(qū)留下您的想法 :-)

0x01 準(zhǔn)備

按著以前積累的經(jīng)驗(yàn), 我們這里, 先快速創(chuàng)建一個(gè)自定義插件,名稱為sum-api
下面是兩個(gè)文件的代碼:

handler.lua

local BasePlugin    = require "kong.plugins.base_plugin"
local SumHandler    = BasePlugin:extend()

SumHandler.VERSION  = "1.0.0"
SumHandler.PRIORITY = 10

function SumHandler:access(config)
  local rst      = {}
  return kong.response.exit(200, rst,
    {
      ["Content-Type"] = "application/json",
    })
end
return SumHandler

schema.lua

local typedefs     = require "kong.db.schema.typedefs"
local colon_string_array = {
  type = "array",
  default = {},
  elements = { type = "string", match = "^[^:]+:.*$" },
}
return {
  name   = "robot",
  fields = {
    { protocols = typedefs.protocols_http },
    { config = {
      type   = "record",
      fields = {
        { sitename = colon_string_array }
      },
    },
    },
  },
}

接下來, 修改/etc/kong/kong.conf, 加載插件名稱 sum-api, 并重啟服務(wù)kong restart.
然后按照下面的圖片順序, 添加一個(gè)的router 取名為 /sum-api,并啟用我們插件.

選擇Service

添加Router

設(shè)置一個(gè)不存在的Router: /sum-api

選擇Router

為此Router添加插件

選擇Sum Api插件

插件參數(shù)設(shè)置

OK, 到此準(zhǔn)備工作完成.
接下來的流程就是:

修改代碼
重啟服務(wù) kong restart
校驗(yàn)接口 curl -i 'http://aaa.com/sum-api?a=1&b=2'

0x02 開發(fā)簡單接口服務(wù)

這里先開發(fā)一個(gè)簡單的例子: 在URL里給出兩個(gè)參數(shù)a和b,在Lua插件里直接返回計(jì)算結(jié)果.
返回格式為,API常用格式:JSON

話不多說, 直接上代碼:

-- handler.lua
local BasePlugin    = require "kong.plugins.base_plugin"

local SumHandler    = BasePlugin:extend()

SumHandler.VERSION  = "1.0.0"
SumHandler.PRIORITY = 10

function SumHandler:access(config)
  -- 從URL里提取參數(shù), 如果沒有的話, 給默認(rèn)值 '0'
  local a        = kong.request.get_query_arg('a') or '0'
  local b        = kong.request.get_query_arg('b') or '0'
  -- String轉(zhuǎn)型為數(shù)值型
  local sum      = tonumber(a) + tonumber(b)

  -- 創(chuàng)建一個(gè)Lua Table
  local rst      = {}
  rst["errCode"] = 0
  -- Lua的字符串拼接
  rst["msg"]     = a .. '+' .. b .. '=' .. sum

  -- 這里直接向客戶端返回結(jié)果
  return kong.response.exit(200, rst,
    {
      ["Content-Type"] = "application/json",
    })
end

return SumHandler

跑接口看一下結(jié)果:

sum-api

恩, 朕很滿意 : )

0x03 使用redis功能

redis簡易安裝教程

yum install epel-release
yum install redis
service redis start

redis驗(yàn)證

功能開發(fā)

我們?yōu)樯厦娴慕涌谠黾右粋€(gè)訪問次數(shù)的信息
同時(shí), openresty中已經(jīng)包含了redis的操作庫, 所以這個(gè)功能實(shí)現(xiàn)起來不難

-- handler.lua
local BasePlugin    = require "kong.plugins.base_plugin"
-- 調(diào)用模塊
local redisUtil     = require "kong.plugins.sum-api.redisUtil"
local redis         = redisUtil.new()

local SumHandler    = BasePlugin:extend()

SumHandler.VERSION  = "1.0.0"
SumHandler.PRIORITY = 10

function SumHandler:access(config)
  local a        = kong.request.get_query_arg('a') or '0'
  local b        = kong.request.get_query_arg('b') or '0'
  local sum      = tonumber(a) + tonumber(b)
  
  -- 調(diào)用redis
  local res, err = redis:exec(
    function(red)
      red:init_pipeline()
      red:incr('access_count')
      return red:commit_pipeline()
    end
  )

  local rst      = {}
  rst["errCode"] = 0
  rst["msg"]     = a .. '+' .. b .. '=' .. sum
  rst["count"]   = res

  return kong.response.exit(200, rst,
    {
      ["Content-Type"] = "application/json",
    })
end

return SumHandler

redisUtil.lua

local redis        = require "resty/redis"

local log          = ngx.log
local ERR          = ngx.ERR
local setmetatable = setmetatable

local _M           = {

}

local mt           = { __index = _M }

local function errlog(...)
  log(ERR, "Redis: ", ...)
end

function _M.exec(self, func)

  local red = redis:new()
  red:set_timeout(self.timeout)

  local ok, err = red:connect(self.host, self.port)
  if not ok then
    errlog("Cannot connect, host: " .. self.host .. ", port: " .. self.port)
    return nil, err
  end

  if self.password ~= '' then
    local count
    count, err = red:get_reused_times()
    if 0 == count then
      ok, err = red:auth(self.password)
      if not ok then
        ngx.say("failed to auth: ", err)
        return
      end
    elseif err then
      ngx.say("failed to get reused times: ", err)
      return
    end
  end
  red:select(self.database)

  local res, err = func(red)
  if res then
    local ok, err = red:set_keepalive(self.max_idle_time, self.pool_size)
    if not ok then
      red:close()
    end
  end
  return res, err
end

function _M.new(opts)
  local config = opts or {}
  local self   = {
    host          = config.host or "127.0.0.1",
    password      = config.password or '',
    port          = config.port or 6379,
    timeout       = config.timeout or 5000,
    database      = config.database or 0,
    max_idle_time = config.max_idle_time or 60000,
    pool_size     = config.pool_size or 100
  }
  return setmetatable(self, mt)
end

return _M

程序代碼結(jié)構(gòu)圖:

代碼結(jié)構(gòu)

多次訪問接口,驗(yàn)證結(jié)果

訪問次數(shù)

完美, 收工!

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