[cloud native] record of feign custom configuration of microservices

Preface ：
Recently, I am learning about micro Services , Read the relevant courses of dark horse , Will relate Feign The knowledge of has summed up some , I hope I can help you guys and deepen your impression
If there is anything to be improved in the article, please give me more advice
Xiao Wei first thanked everyone for their support

🥤Feign Custom configuration for

Feign There are two ways to customize the configuration ：java Code configuration and Attribute configuration , These two configurations are described below .

Here we start with Feign Log configuration is an example ,Feign No logs are printed by default , When an exception occurs in the remote call , Subsequent debugging will want to see the details of the entire request , You can configure Feign Log requests .

Feign Log level of

1.NONE（ The default value is ）： Don't log anything

2.BASIC： Only the request method is recorded 、URL、 Response status code and execution time

3.HEADERS： Record BASIC Level based , Recording requests and responses header

4.FULL： Recording requests and responses header、body And metadata

Of course, there are other things besides logs , The following is presented in the form of a table ：

type	effect	explain
feign.Logger.Level	Modify log level	Contains four different levels ：NONE、BASIC、HEADERS、FULL
feign.codec.Decoder	The parser that responds to the result	http Analyze the result of remote call , For example, parsing json String is java object
feign.codec.Encoder	Request parameter encoding	Encode the request parameters , Easy to pass http Request to send
feign. Contract	Supported annotation formats	The default is SpringMVC Annotations
feign. Retryer	Failure retry mechanism	Retry mechanism for request failure , The default is No , However, it will be used Ribbon Retry

In general , The default value can meet our use , If you want to customize , Just create a custom @Bean Override default Bean that will do .

The configuration file

Modify based on the configuration file feign The log level can be for a single service ：

feign:  
  client:
    config: 
      userservice: #  Configuration for a microservice 
        loggerLevel: FULL #  The level of logging  

It can also be for all services ：

feign:  
  client:
    config: 
      default: #  Here we use default Global configuration , If you write the service name , It is the configuration for a micro service 
        loggerLevel: FULL #  The level of logging  

There are four levels of logs ：

• NONE： No log information is recorded , This is the default .
• BASIC： Record only the requested method ,URL And the response status code and execution time
• HEADERS： stay BASIC On the basis of , Additionally, the request and response header information is recorded
• FULL： Record details of all requests and responses , Including header information 、 Request body 、 Metadata .

🧁Java Code configuration

It can also be based on Java Code to modify the log level , Foretell a class , Then declare a Logger.Level The object of ：

public class DefaultFeignConfiguration  {
    
    @Bean
    public Logger.Level feignLogLevel(){
    
        return Logger.Level.BASIC; //  Log level is BASIC
    }
}

If you want to Global effect , Put it in the... Of the startup class @EnableFeignClients In this note ：

@EnableFeignClients(defaultConfiguration = DefaultFeignConfiguration .class) 

If it is Partial effect , Then put it in the corresponding @FeignClient In this note ：

@FeignClient(value = "userservice", configuration = DefaultFeignConfiguration .class) 

Feign Tuning of

Feign Performance tuning book ⾝ Very good performance ⾼, But you can still optimize .

feign The underlying client implementation ：

URLConnection： Default implementation , Connection pooling is not supported

Apche HttpClient: Support connection pool

OKHttp: Support connection pool

So optimize feign The performance of

1. Use the connection pool instead of the default connection pool URLConnection

2. The level of logging ： meanwhile ⽇ The level of ambition is different , The performance consumed is also different , Use as much as possible Basic Level or none

You can make ⽤Apche HttpClient or OKHttp Into the ⾏ Optimize

Feign Bottom layer initiation http request , Rely on other frameworks . Its underlying client implementation includes ：

•URLConnection： Default implementation , Connection pooling is not supported

•Apache HttpClient ： Support connection pool

•OKHttp： Support connection pool

So improve Feign The main means of performance is to use Connection pool Instead of default URLConnection.

Here we use Apache Of HttpClient To demonstrate .

First step Introduce dependencies

stay order-service Of pom Introduce in the file Apache Of HttpClient rely on ：

<!--httpClient Dependence  -->
<dependency>
    <groupId>io.github.openfeign</groupId>
    <artifactId>feign-httpclient</artifactId>
</dependency>

2） Configure connection pool

stay order-service Of application.yml Add configuration in ：

feign:
  client:
    config:
      default: # default Global configuration 
        loggerLevel: BASIC #  The level of logging ,BASIC Is the basic request and response information 
  httpclient:
    enabled: true #  Turn on feign Yes HttpClient Support for 
    max-connections: 200 #  Maximum number of connections 
    max-connections-per-route: 50 #  Maximum number of connections per path 

stay FeignClientFactoryBean Medium loadBalance Break in the method , and Debug Mode start order-service service , The bottom is Apache HttpClient.

1. Try to use the log level basic

2. Use HttpClient or OKHttp Instead of URLConnection

① introduce feign-httpClient rely on

② Profile on httpClient function , Set connection pool parameters

This is the end of the article , If you have any questions, please point out
Thank you again for your support