Pretty print JSON output of Spring Boot Actuator endpoints

Question

Spring Boot Actuator provides several endpoints to monitor an application as:

/metrics
/b         


        

Answer 1

As per http://docs.spring.io/spring-boot/docs/current/reference/html/howto-spring-mvc.html#howto-customize-the-jackson-objectmapper, the official way to enable pretty print with Jackson in Spring Boot (1.2.2 at least) is to set the following property:

 # Pretty-print JSON responses
 spring.jackson.serialization.indent_output=true

Answer 2

For Spring Boot 1.5.1 I have in my YML file:

spring:
  jackson:
    serialization:
      INDENT_OUTPUT: true

@BertrandRenuart answer was the closest, but by IDE did not see indent_output as correct.

Answer 3

this not working

spring.jackson.serialization.INDENT_OUTPUT=true

this is working spring.jackson.serialization.indent-output=true

Answer 4

Instead of using curl I like to use httpie as a http command line client:

http http://localhost:8080/metrics

This would already format and syntax highlight the json response without having to pipe the output into another command. Also the command syntax is a bit more human friendly.

Answer 5

Unfortunately, the application property

spring.jackson.serialization.INDENT_OUTPUT

did not work for me (spring boot versions 1.2.6 to 1.4.0.RELEASE). Instead, in my extension of WebMvcConfigurerAdapter, I've overridden configureMessageConverters() and added my own Jackson2ObjectMapperBuilder:

@Configuration
@EnableWebMvc
public class WebMvcConfig extends WebMvcConfigurerAdapter {
   ...
    private MappingJackson2HttpMessageConverter jacksonMessageConverter() {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder()
                .featuresToDisable(SerializationFeature.FAIL_ON_EMPTY_BEANS,
                        SerializationFeature.WRITE_CHAR_ARRAYS_AS_JSON_ARRAYS)
                .featuresToEnable(SerializationFeature.INDENT_OUTPUT).modulesToInstall(hibernate4Module());
        // can use this instead of featuresToEnable(...)
        builder.indentOutput(true);
        return new MappingJackson2HttpMessageConverter(builder.build());
    }


    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(jacksonMessageConverter());
        super.configureMessageConverters(converters);
    }

   ...

}

That seem to do the trick for me on Spring boot 1.4.0.RELEASE and my actuator output is now pretty printed (along with every other json output)

Answer 6

In case somebody with Spring Boot 2 (2.1.1 in my case) stumbles over this question as I did: We faced the same problem, and none of the answers helped for 2.1.1.

So what we did was to replace the existing endpoint (health in our case) with a new one. I described it at the end of this answer. And yes, this limits our solution to this single endpoint, but on the other hand it has the advantage of being able to format the output in any way you want - including pretty print JSON, but also output styled HTML if requested (by a service technician in a browser in our case). Note the produces attribute of @ReadOperation to achieve that.