Zookeeper

Use ZooKeeper as Kitex’s service governance configuration center

Install

go get github.com/kitex-contrib/config-zookeeper

Suite

The configuration center adapter of zookeeper, kitex uses WithSuite to convert the configuration in zookeeper into the governance feature configuration of kitex.

The following is a complete usage example:

Server

type ZookeeperServerSuite struct {
	zookeeperClient zookeeper.Client // zookeeper client in config-zookeeper
	service         string // server-side service name
	opts            utils.Options // customize func
}

Function Signature:

func NewSuite(service string, cli zookeeper.Client, opts ...utils.Option) *ZookeeperServerSuite

Sample code:

package main

import (
	"context"
	"log"

	"github.com/cloudwego/kitex-examples/kitex_gen/api"
	"github.com/cloudwego/kitex-examples/kitex_gen/api/echo"
	"github.com/cloudwego/kitex/pkg/klog"
	"github.com/cloudwego/kitex/pkg/rpcinfo"
	"github.com/cloudwego/kitex/server"
	zookeeperServer "github.com/kitex-contrib/config-zookeeper/server"
	"github.com/kitex-contrib/config-zookeeper/zookeeper"
)

var _ api.Echo = &EchoImpl{}

type EchoImpl struct{}

func (s *EchoImpl) Echo(ctx context.Context, req *api.Request) (resp *api.Response, err error) {
	klog.Info("echo called")
	return &api.Response{Message: req.Message}, nil
}

func main() {
	zookeeperClient, err := zookeeper.NewClient(zookeeper.Options{})
	if err != nil {
		panic(err)
	}
	serviceName := "ServiceName" // your server-side service name
	svr := echo.NewServer(
		new(EchoImpl),
		server.WithServerBasicInfo(&rpcinfo.EndpointBasicInfo{ServiceName: serviceName}),
		server.WithSuite(zookeeperServer.NewSuite(serviceName, zookeeperClient)),
	)
	if err := svr.Run(); err != nil {
		log.Println("server stopped with error:", err)
	} else {
		log.Println("server stopped")
	}
}

Client

type ZookeeperClientSuite struct {
	zookeeperClient zookeeper.Client // zookeeper client in config-zookeeper
	service         string // server-side service name
	client          string // client-side service name
	opts            utils.Options // customize func
}

Function Signature:

func NewSuite(service, client string, cli zookeeper.Client, opts ...utils.Option) *ZookeeperClientSuite

Sample code:

package main

import (
	"context"
	"log"
	"time"

	"github.com/cloudwego/kitex-examples/kitex_gen/api"
	"github.com/cloudwego/kitex-examples/kitex_gen/api/echo"
	"github.com/cloudwego/kitex/client"
	"github.com/cloudwego/kitex/pkg/klog"
	zookeeperclient "github.com/kitex-contrib/config-zookeeper/client"
	"github.com/kitex-contrib/config-zookeeper/utils"
	"github.com/kitex-contrib/config-zookeeper/zookeeper"
)

type configLog struct{}

func (cl *configLog) Apply(opt *utils.Options) {
	fn := func(k *zookeeper.ConfigParam) {
		klog.Infof("zookeeper config %v", k)
	}
	opt.ZookeeperCustomFunctions = append(opt.ZookeeperCustomFunctions, fn)
}

func main() {
	zookeeperClient, err := zookeeper.NewClient(zookeeper.Options{})
	if err != nil {
		panic(err)
	}

	cl := configLog{}

	serviceName := "ServiceName" // your server-side service name
	clientName := "ClientName"   // your client-side service name
	client, err := echo.NewClient(
		serviceName,
		client.WithHostPorts("0.0.0.0:8888"),
		client.WithSuite(zookeeperclient.NewSuite(serviceName, clientName, zookeeperClient, &cl)),
	)
	if err != nil {
		log.Fatal(err)
	}
}

NewClient

Create client.

Function Signature:

func NewClient(opts Options) (Client, error)

Sample code:

package main

import "github.com/kitex-contrib/config-zookeeper/zookeeper"

func main() {
	zookeeperClient, err := zookeeper.NewClient(zookeeper.Options{})
	if err != nil {
		panic(err)
	}
}

SetParser

Set a custom parser for deserializing zookeeper configuration. If not specified, it will be the default parser.

The default parser parses configuration in json format.

Function Signature:

func (c *client) SetParser(parser ConfigParser)

type ConfigParser interface {
	Decode(data string, config interface{}) error
}

Sample code:

Set the configuration for parsing yaml types.

package main

import (
	"github.com/kitex-contrib/config-zookeeper/zookeeper"
	"gopkg.in/yaml.v3"
)

func (p *parser) Decode(data string, config interface{}) error {
	return yaml.Unmarshal([]byte(data), config)
}

type parser struct{}

func main() {
	zookeeperClient, err := zookeeper.NewClient(zookeeper.Options{})
	if err != nil {
		panic(err)
	}
	zookeeperClient.SetParser(&parser{})
}

ZooKeeper Configuration

Options Struct

type Options struct {
	Servers          []string
	Prefix           string
	ServerPathFormat string
	ClientPathFormat string
	CustomLogger     zk.Logger
	ConfigParser     ConfigParser
}

Options Variable

type ConfigParam struct {
	Prefix string
	Path   string
}

The final path in kitex-contrib/config-zookeeper is a combination of Prefix and Path in ConfigParam: param.Prefix + "/" + param.Path

Variable Name Default Value Introduction
Servers 127.0.0.1:2181 Zookeeper server nodes
Prefix /KitexConfig The prefix of Zookeeper
ClientPathFormat {{.ClientServiceName}}/{{.ServerServiceName}}/{{.Category}} Use go template syntax rendering to generate the appropriate ID, and use ClientServiceName ServiceName Category three metadata that can be customised
ServerPathFormat {{.ServerServiceName}}/{{.Category}} Use go template syntax rendering to generate the appropriate ID, and use ServiceName Category two metadatas that can be customised
ConfigParser defaultConfigParser The default is the parser that parses json

Governance Policy

The configPath and configPrefix in the following example use default values, the service name is ServiceName and the client name is ClientName.

Rate Limit

Category=limit

Currently, current limiting only supports the server side, so ClientServiceName is empty.

JSON Schema

Variable Introduction
connection_limit Maximum concurrent connections
qps_limit Maximum request number every 100ms

Example:

configPath: /KitexConfig/ServiceName/limit

{
  "connection_limit": 100,
  "qps_limit": 2000
}

Note:

  • The granularity of the current limit configuration is server global, regardless of client or method.
  • Not configured or value is 0 means not enabled.
  • connection_limit and qps_limit can be configured independently, e.g. connection_limit = 100, qps_limit = 0

Retry Policy

Category=retry

JSON Schema

Variable Introduction
type 0: failure_policy 1: backup_policy
failure_policy.backoff_policy Can only be set one of fixed none random

Example:

configPath: /KitexConfig/ClientName/ServiceName/retry

{
    "*": {
        "enable": true,
        "type": 0,
        "failure_policy": {
            "stop_policy": {
                "max_retry_times": 3,
                "max_duration_ms": 2000,
                "cb_policy": {
                    "error_rate": 0.3
                }
            },
            "backoff_policy": {
                "backoff_type": "fixed",
                "cfg_items": {
                    "fix_ms": 50
                }
            },
            "retry_same_node": false
        }
    },
    "echo": {
        "enable": true,
        "type": 1,
        "backup_policy": {
            "retry_delay_ms": 100,
            "retry_same_node": false,
            "stop_policy": {
                "max_retry_times": 2,
                "max_duration_ms": 300,
                "cb_policy": {
                    "error_rate": 0.2
                }
            }
        }
    }
}

Note: retry.Container has built-in support for specifying the default configuration using the * wildcard (see the getRetryer method for details).

RPC Timeout

Category=rpc_timeout

JSON Schema

Example:

configPath: /KitexConfig/ClientName/ServiceName/rpc_timeout

{
  "*": {
    "conn_timeout_ms": 100,
    "rpc_timeout_ms": 3000
  },
  "echo": {
    "conn_timeout_ms": 50,
    "rpc_timeout_ms": 1000
  }
}

Note: The circuit breaker implementation of kitex does not currently support changing the global default configuration (see initServiceCB for details).

Circuit Break

Category=circuit_break

JSON Schema

Variable Introduction
min_sample Minimum statistical sample number

Example:

The echo method uses the following configuration (0.3, 100) and other methods use the global default configuration (0.5, 200)

configPath: /KitexConfig/ClientName/ServiceName/circuit_break

{
  "echo": {
    "enable": true,
    "err_rate": 0.3,
    "min_sample": 100
  }
}

Last modified February 29, 2024 : doc: optimize cli document (#982) (6126084)