Apollo

Use apollo as Kitex’s service governance configuration center

Install

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

Suite

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

The following is a complete usage example:

Server

type ApolloServerSuite struct {
	apolloClient apollo.Client // apollo client in config-apollo
	service      string // server-side service name
	opts         utils.Options // customize func
}

Function Signature:

func NewSuite(service string, cli apollo.Client, options ...utils.Option) *ApolloServerSuite

Sample code:

package main

import (
	"context"
	"log"
	"net"

	"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"
	"github.com/kitex-contrib/config-apollo/apollo"
	apolloserver "github.com/kitex-contrib/config-apollo/server"
	"github.com/kitex-contrib/config-apollo/utils"
)

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() {
	klog.SetLevel(klog.LevelDebug)
	apolloClient, err := apollo.NewClient(apollo.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(apolloserver.NewSuite(serviceName, apolloClient)),
	)
	if err := svr.Run(); err != nil {
		log.Println("server stopped with error:", err)
	} else {
		log.Println("server stopped")
	}
}

Client

type ApolloClientSuite struct {
	apolloClient apollo.Client // apollo client in config-apollo
	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 apollo.Client,options ...utils.Option) *ApolloClientSuite

Sample code:

package main

import (
	"log"

	"github.com/cloudwego/kitex-examples/kitex_gen/api/echo"
	"github.com/cloudwego/kitex/client"
	"github.com/kitex-contrib/config-apollo/apollo"
	apolloclient "github.com/kitex-contrib/config-apollo/client"
)

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

	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(apolloclient.NewSuite(serviceName, clientName, apolloClient)),
	)
	if err != nil {
		log.Fatal(err)
	}
}

NewClient

Create client.

Function Signature:

func NewClient(opts Options, optsfunc ...OptionFunc) (Client, error)

Sample code:

package main

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

func main() {
	apolloClient, err := apollo.NewClient(apollo.Options{}, apollo.WithApolloOption())
	if err != nil {
		panic(err)
	}
}

SetParser

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

The default parser parses configuration in json format.(only parsing JSON format is supported currently)

Function Signature:

func (c *client) SetParser(parser ConfigParser)

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

Sample code:

Set the configuration for parsing json types.

package main

import (
	"github.com/bytedance/sonic"
	"github.com/kitex-contrib/config-apollo/apollo"
)

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

type parser struct{}

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

Apollo Configuration

Options Struct

type Options struct {
	ConfigServerURL string
	AppID           string
	Cluster         string
	ServerKeyFormat string
	ClientKeyFormat string
	ApolloOptions   []agollo.Option
	ConfigParser    ConfigParser
}

Options Variable

type ConfigParamConfig struct {
	Category          string
	ClientServiceName string
	ServerServiceName string
}

The type of the namespace in kitex contrib/configure Apollo is properties, and the format reference for the key is as follows: ClientKeyFormat or ServerKeyFormat, with ‘value’ fixed in JSON format

参数 变量默认值 作用
ConfigServerURL 127.0.0.1:8080 apollo config service address
AppID KitexApp appid of apollo (Uniqueness constraint / Length limit of 32 characters)
ClientKeyFormat {{.ClientServiceName}}.{{.ServerServiceName}} Using the go template syntax to render and generate the corresponding ID, using two metadata: ClientServiceName and ServiceName (Length limit of 128 characters)
ServerKeyFormat {{.ServerServiceName}} Using the go template Syntax rendering generates corresponding IDs, using ‘ServiceName’ as a single metadata (Length limit of 128 characters)
Cluster default Using default values, users can assign values as needed (Length limit of 32 characters)
ConfigParser defaultConfigParser The default parser, which defaults to parsing json format data (only parsing JSON format is supported currently)

Governance Policy

The namespace in the following example uses fixed policy values, with default values for AppID and Cluster. 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:

namespace: limit

key: ServiceName

{
  "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:

namespace: retry

key: ClientName.ServiceName

{
    "*": {  
        "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:

namespace: rpc_timeout

key: ClientName.ServiceName

{
  "*": {
    "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:

namespace: circuit_break

key: ClientName.ServiceName

The echo method uses the following configuration (0.3, 100) and other methods use the global default configuration (0.5, 200)
{
  "echo": {
    "enable": true,
    "err_rate": 0.3, 
    "min_sample": 100 
  }
}

Last modified March 1, 2024 : Update tutorial.md ,fixed an inconsistency (#986) (89c92e3)