OpenFeign combat development and parameter tuning

OpenFeign is basically used

OpenFeign profile

OpenFeign is a declarative HTTP client that makes it very easy to write web service clients by creating an interface and adding annotations to the interface. OpenFeign’s predecessor was Feign, which is now defunct. OpenFeign is the annotation that SpringCloud supports Spring MVC based on Feign, and generates implementation classes to do load balancing and call other services through dynamic proxy.

Ribbon+RestTemplate is cumbersome and OpenFeign can simplify development

The basic use

Take the example of a user service invoking a commodity

The user service is configured with OpenFeign

1. Import dependence

   <dependency>
   
      <groupId>org.springframework.cloud</groupId>
   
      <artifactId>spring-cloud-starter-openfeign</artifactId>
   
     </dependency>
   
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2. Annotate the startup class

   

Write the called interface in the commodity service (no-parameter interface test)

Write service calls directly using Feign in the user service

1. Create a plain Java interface

   

2. A client that declares the current interface to be Feign through annotations

   

3. Write the methods of the service invocation in the Feign interface

   

4. Use the Feign interface in the Controller of the user service

   

5. Start all services two goods services one user service registry access user services observe service calls

   Controllers accessing user services can see the effect of load balancing

   

   

6. process

   

Handling of passing parameters

The parameters are passed in JSON and are actually RestFul requests

1. /{} Splice parameters

   1. Example of invoked interface [Goods and Services]

      

   2. Feign Interface Example [User Service]

      

2. ? The concatenation parameter corresponds to the common request type Get request

   1. Example of invoked interface [Goods and Services]

      

   2. Feign Interface Example [User Service]

      

3. The request body pass parameter corresponds to a common request Post request

   1. Example of invoked interface [Goods and Services]

      

   2. Feign Interface Example [User Service]

      

Open the log

Unlike RestTemplate, Feign encapsulates the details of the request more thoroughly. It does not see the request, the parameters of the request, or the state of the response. To see the details of the request, Feign logs are required

Feign log configuration

1. Configure class @bean

@Bean

public Logger.Level feignConfig(a){

    return Logger.Level.FULL;

}

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2. Enable the log function for the package where the Feign interface resides in the configuration file

Restart the project with the above configuration and use the Feign service call again to see the following log:

Feign parameter tuning

1. Replace OKHttp

By default, spring Cloud Feign uses THE JDK’s HttpURLConnection for HTTP components to make calls between sub-services, not thread pools.

There are two thread pools to choose from: HttpClient and OKHttp. OKHttp is recommended because request encapsulation is very easy to use and performance is ok.

Add the dependent

<dependency>

    <groupId>com.squareup.okhttp3</groupId>

    <artifactId>okhttp</artifactId>

</dependency>

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Modifying a Configuration File

feign:

  okhttp:

    enabled: true

  httpclient:

    enabled: false

    max-connections: 1000

    max-connections-per-route: 100

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Max-connections: indicates the maximum number of connections

Max-connections-per-route: indicates the number of connections per URL

2. Enable Feign request response compression

Compression can effectively save network resources, but increases CPU pressure. Therefore, you are advised to increase the size of the least compressed document

## Enable Feign request response compression

feign.compression.request.enabled=true



feign.compression.response.enabled=true

Configure the compressed document type and the minimum compressed document size

feign.compression.request.mime-types=text/xml,application/xml,application/json



feign.compression.request.min-request-size=2048

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