Feign logging not working

Question

I'm trying to get logging working for each request from a Feign rest client. However I cannot get the logging to work, while 'standard' Slf4j logging does work.

I have the following:

public MyClient() {
        initConnectionProperties();

        this.service = Feign.builder()
                .contract(new JAXRSContract())
                .decoder(getJacksonDecoder())
                .encoder(getJacksonEncoder())


                .requestInterceptor(new BasicAuthRequestInterceptor(user, password))
                //.client(new OkHttpClient())
                .logger(new Slf4jLogger(MyClient.class)) //not working

                .logLevel(feign.Logger.Level.BASIC)
                .target(MyClient.class, this.url);
        logger.info("Connection parameters: url = " + url + ", user = " + user); //Is working
    }

Answer 1

private void setup() {
    //...
    feignBuilder.logger(new MyLogger());
    feignBuilder.logLevel(Logger.Level.FULL);
}

private static class MyLogger extends Logger {
    @Override
    protected void log(String s, String s1, Object... objects) {
        System.out.println(String.format(s + s1, objects)); // Change me!
    }
}

Answer 2

You may also need to configure your log4j logging level for feign to DEBUG. If you are using spring boot, what worked for me is:

curl -X POST http://localhost/loggers/feign -H 'Content-Type: application/json' -d '{"configuredLevel": "DEBUG"}'

Answer 3

First you need to set the logging level for your feign client class to DEBUG, as Maverick already mentioned in his answer.

Then if you use Spring Boot, beside the option to create @Configuration classes as Niraj already mentioned in his answer, you can configure each client individually in you application properties/yml config file:

feign: client: config: the_name_of_your_feign_client: connectTimeout: 5000 readTimeout: 5000 loggerLevel: basic

Or use default instead of the_name_of_your_feign_client to configure all your feign clients in the same way:

feign: client: config: default: connectTimeout: 5000 readTimeout: 5000 loggerLevel: basic

Answer 4

This is how i was able to log using Custom Config class

Note Feign logging only responds to the DEBUG level.

Config Class

@Configuration
public class UserClientConfig {

    @Bean
    Logger.Level feignLoggerLevel() {
        return Logger.Level.HEADERS;
    }
} 

Client

@FeignClient(name = "User", url = "http://localhost:8080",configuration=UserClientConfig.class)
public interface UserClient {

    @RequestMapping(method = RequestMethod.GET, value = "/user")
    List<User> getAllUsers();    

}

application.properties

logging.level.<pcakgepath>.UserClient: DEBUG

Answer 5

You need to configure logging in application.properties as below:

logging.level.<package path>.MyClient=DEBUG

If you're using application.yml then:

logging.level.<package path>.MyClient: DEBUG

The log level can be set to tell Feign how much to log.

Options are:

• NONE, No logging (DEFAULT)
• BASIC, Log only the request method and URL and the response status code and execution time
• HEADERS, Log the basic information along with request and response headers
• FULL, Log the headers, body, and metadata for both requests and responses

Example:

logLevel(feign.Logger.Level.NONE)
or
logLevel(feign.Logger.Level.BASIC)
or
logLevel(feign.Logger.Level.HEADERS)
or
logLevel(feign.Logger.Level.FULL)

For more details, you can refer this

Answer 6

I hadn't set a client, and my client calls were failing, and logging wasn't working.. once I added OkHttpClient and changed logback.xml file, worked fine

    MyApi myApi = Feign.builder()
            .client(new OkHttpClient())
            .decoder(new JacksonDecoder())
            .encoder(new JacksonEncoder())
            .logger(new Slf4jLogger())
            .logLevel(feign.Logger.Level.FULL)
            .target(MyApi.class, "http://localhost:8082");

this is logback.xml

<configuration>
    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <pattern>%d %green([%thread]) %highlight(%level) %logger{50} - %msg%n</pattern>
        </encoder>
    </appender>
    <logger name="feign.Logger" level="DEBUG" />
    <root level="INFO">
        <appender-ref ref="STDOUT"/>
    </root>
</configuration>