自定义kong plugin在k8s中的使用

背景：在小程序上线审核时间段内，如果后端代码直接上线到线上，如果后端不兼容上个版本的接口，可能会导致前端某些接口请求失败。不断的兼容接口，会导致代码混乱，如果是大版本的迭代，有时候也很难去兼容。在审核期间，新版本接口走灰度服务器，老接口还是走线上服务器。审核通过后，小程序和接口同时提交上线，那边就不存在什么问题了。

灰度服务总体架构

Kong 灰度服务.png

kong plugin gray服务

plugins路径
/usr/local/share/lua/5.1/kong/plugins/gray
├── client_redis.lua
├── handler.lua
└── schema.lua

handler.lua

local BasePlugin = require "kong.plugins.base_plugin"
local utils = require "kong.tools.utils"
local client_redis = require "kong.plugins.gray.client_redis"
local xml = require "pl.xml"

local function get_redis_conf(conf)
  local redis_conf = {
    ["ip"] = conf.redis_host,
    ["port"] = conf.redis_port,
    ["passwd"] = conf.redis_password,
    ["timeout"]=conf.redis_timeout,
    ['database']=conf.redis_database}
  return redis_conf
end

local GrayHandler = BasePlugin:extend()

GrayHandler.PRIORITY = 2000

function GrayHandler:new()
  GrayHandler.super.new(self, "gray")
end

function GrayHandler:access(conf)
  GrayHandler.super.access(self)
  -- 获取版本号
  local method = kong.request.get_method()
  kong.log("method=" .. method)
  local version
  if method == "GET" then
     version = kong.request.get_query_arg("v")
  elseif method == "POST" then
     local body, err, mimetype = kong.request.get_body()
     if body ~= nil then
       version = body.v
     end
  else
    return
  end
  kong.log("version type=" .. type(version))
  if version == nil then
    return
  end

  local host = kong.request.get_host()
  --kong.log("host=" .. host)
  local arr = utils.split(host, ".")
  local prefix_host = arr[1]
  local key = "gray:"..prefix_host
  kong.log("host=" .. host .."\tkey=" .. key)
  --kong.log("host=" .. conf.redis_host.."\tport=" .. conf.redis_port.."\tpasswd=" .. conf.redis_password.."\ttimeout=" .. conf.redis_timeout.."\tdatabase="..conf.redis_database)

  local redis_conf = get_redis_conf(conf)
  --kong.log("timeout=" .. redis_conf['timeout'])
  --local robj = client_redis:new()
  local conn = client_redis:connection(redis_conf)
  local gray_version,err = conn:get(key)
  --kong.log("gray_version type=" .. type(gray_version))
  if gray_version == ngx.null then
    return
  end
  local log_str = "key=" .. key .. "\tversion=" .. version .. "\tgray_version=" .. gray_version
  kong.log(log_str)

  if version ~= nil and gray_version ~= ngx.null and gray_version == version then
    local upstream = conf.upstream
    kong.log(" into set upstream=" .. upstream)
    local ok, err = kong.service.set_upstream(upstream)
    if not ok then
      kong.log.err(err)
    end
  end

end

return GrayHandler

schema.lua

local typedefs = require "kong.db.schema.typedefs"
return {
  name = "gray",
  fields = {
    { consumer = typedefs.no_consumer },
    { protocols = typedefs.protocols_http },
    { config={
       type = "record",
       fields = {
         { redis_host = { type = "string", required = true },},
         { redis_port = { type = "number", default = 6379 },},
         { redis_password = { type = "string", required = true},},
         { redis_database = { type = "number", default = 0},},
         { redis_timeout = { type = "number", default = 1000},},
         { upstream = { type = "string", required = true},},
       }
      }
    }
  }
}

client_redis.lua

local redis = require "resty.redis"
local _M = {}
    function _M:new()
      local o = {}
      setmetatable(o, self)
      self.__index = self;
      return o
    end

    function _M:connection(config)
        --kong.log("into redis")
        --kong.log("redis:ip=" .. config['ip']  .. "\tport=" .. config['port'])
        --kong.log("redis:ip=" .. config['ip']  .. "\tport=" .. config['port'] .. "\ttimeout=" .. config['timeout'])
        local red = redis:new()
        red:set_timeout(config['timeout'])

        local ok, err = red:connect(config['ip'],config['port'])
        if not ok then
            ngx.log(ngx.ERR, 'failed to connection redis',err)
            return nil
        end

        local ok, err = red:auth(config['passwd'])
        if not ok then
            red:close()
            ngx.log(ngx.ERR, 'Auth not pass')
            return nil
        end
        red:select(config['database'])
        return red
    end

return _M

将代码添加到configmap

kubectl create configmap kong-plugin-gray-cm --from-file=/usr/local/share/lua/5.1/kong/plugins/gray

gray.yaml

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: kong-plugin-gray
  labels:
    global: "false"
config:
  redis_host: "172.16.1.1"
  redis_port: 6379
  redis_password: "xxxxxxx"
  redis_database: 0
  redis_timeout: 1000
  upstream: "k8s-gray-mobile.default.80.svc"
plugin: gray

创建KongPluin

kubectl apply -f gray.yaml

ingress中注解，需要使用kong-plugin-gray插件

ingress:
  enabled: true
  className: "kong"
  annotations:
    konghq.com/plugins: "kong-plugin-gray"

至此，整个灰度服务流程已完成。