---

title: Tars Plugin
keywords: [“Tars”]
description: Tars Plugin

1. Overview

1.1 Plugin name

• Tars plugin

1.2 Appropriate scenario

• Protocol conversion, a plugin that converts http protocol requests into the Tars framework protocol
• Service Load Balancing.

1.3 Plugin functionality

• Converting http protocol requests to Tars framework protocol.

1.4 Plugin code

• Core Module shenyu-plugin-tars
• Core Class org.apache.shenyu.plugin.tars.TarsPlugin

1.5 Added since which shenyu version

• 2.3.0

2. How to use plugin

2.1 Plugin-use procedure chart

2.2 Import pom

        <dependency>
            <groupId>org.apache.shenyu</groupId>
            <artifactId>shenyu-spring-boot-starter-client-tars</artifactId>
            <version>${shenyu.version}</version>
        </dependency>

2.3 Configure in the client project

1. Configure the Tars configuration in application.yml.

shenyu:
  register:
    registerType: http #zookeeper #etcd #nacos #consul
    serverLists: http://localhost:9095 #localhost:2181 #http://localhost:2379 #localhost:8848
    props:
      username: admin
      password: 123456
  client:
    tars:
      props:
        contextPath: /tars
        appName: tars
        port: 21715
        host: 192.168.41.103 # client IP

2. Add the @ShenyuTarsService and @ShenyuTarsClient and annotation to the interface.

@TarsServant("HelloObj")
@ShenyuTarsService(serviceName = "ShenyuExampleServer.ShenyuExampleApp.HelloObj")
public class HelloServantImpl implements HelloServant {
  
    @Override
    @ShenyuTarsClient("/hello")
    public String hello(final int no, final String name) {
        return String.format("hello no=%s, name=%s, time=%s", no, name, System.currentTimeMillis());
    }
}

2.4 Enable plugin

• In shenyu-admin --> BasicConfig --> Plugin --> tars set Status enabled.

2.5 Config plugin

2.5.1 Config plugin

• multiSelectorHandle：Set to enable multiple selector processing, multiple selector processing services can be configured in the selector list.
• multiRuleHandle：Set to multiple rules processing, configure multiple processing rules in the rule list, it is recommended to configure as single rule.
• threadpool：There are five types of business thread pools: fixed, eager, cached, limited and shared. The first 4 types correspond to the thread pools officially provided by dubbo. Let's talk about shared, as its name implies, all proxy plugins share a shared thread pool, the advantage of this is that it can reduce the number of thread pools, thereby reducing memory and improving resource utilization.
• corethreads：The number of core threads in the business thread pool.
• threads：The maximum number of threads in the business thread pool.
• queues：The length of the blocking queue of the business thread pool, 0 means unbounded blocking queue.

2.5.2 Selector config

Flow needs to be matched by selector.

Automatically configure the selectors with the @ShenyuTarsClient annotation.

2.5.3 Rule Config

After the traffic has been successfully matched by the selector, it will enter the rules for the final traffic matching.

Automatically configure the rules with the @ShenyuTarsClient annotation.

2.5.4 Metadata config

When the Tars application client accesses the Apache ShenYu gateway, it will be automatically registered, and can be viewed in the shenyu-admin backend management system's basic configuration --> metadata management, each Tars interface method, will correspond to a metadata.

• AppName: specifies the name of the application to which the metadata belongs.

• MethodName: the name of the method to call.

• Path: http request path.

• PathDescribe: the description of the path is easy to view.

• ParamsType: the parameters are separated by commas (,) in the order of interface parameter types.

• RpcExpand: other configurations of the Tars interface, which support the JSON format.

  examples：{"loadbalance":"hash","retries":3,"timeout":-1}

  • loadbalance：Load balancing policy, currently supports roundRobin, random and hash.
  • retries：Number of retries to call client timeout failures.
  • timeout：Calling the client's timeout time.

• Interface: The fully qualified class name of the Tars interface.

• RpcType：Auto-registration defaults to Tars.

2.6 Examples

2.6.1 Using ShenYu to access the Tars service

2.6.1.1 Preparation

• Start ShenYu Admin.
• Start Shenyu Bootstrap.

2.6.1.2 Plugin Config

• In shenyu-admin --> BasicConfig --> Plugin --> tars set Status enabled, And adjust the registry configuration as needed.
• Adjust to the actual situation shenyu-examples-tars application.yml configuration in the project and start it.

2.6.2.6 Request service and check result

3. How to disable plugin

• In shenyu-admin --> BasicConfig --> Plugin --> tars set Status disable.