Spring-boot-admin: Allow snake case formatting

[summonwurm]

A client application we have uses Jackson snake case formatting via the spring.jackson.property-naming-strategy: SNAKE_CASE.

When trying to view the environment tab for an instance, there is just a swirling loading gif even though I can see that instances//actuator/env/ is returning JSON data. You can also test this by adding the snake case property to the application settings for the admin server and observing that no applications show.

[joshiste]

I think SBA should support the default format for actuator endpoints. It would be too tedious to support two formats in the UI.

When https://github.com/spring-projects/spring-boot/issues/12951 is resolved you could configure the objectMapper for the business components without affecting the actuator endpoint.

Until then one option (when using SBA 2.0) is to implement a InstanceExchangeFilterFunction which converts the snake-case to camel-case for the ui.

Or you don't reconfigure the global ObjectMapper in Spring Boot but add a HttpMessageConverter which uses snake case and is only active for your business endpoints. Examples for that can be found here: https://stackoverflow.com/questions/43079892

[jacobdong]

@joshiste

1.spring-projects/spring-boot#12951

just resolved health endpoint others are still not work with spring-boot 2.0

2.InstanceExchangeFilterFunction

Can you provide a sample

3.HttpMessageConverter

There are a lot of problems in this, We should modify every client

[joshiste]

https://github.com/spring-projects/spring-boot/issues/12951 is still unresolved....

[joshiste]

If you add this:

 @Bean
    public MappingJackson2HttpMessageConverter actuatorHttpMessageConverter() {
        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter(
            Jackson2ObjectMapperBuilder.json().featuresToDisable(WRITE_DATES_AS_TIMESTAMPS).build());
        converter.setSupportedMediaTypes(
            Collections.singletonList(MediaType.parseMediaType(ActuatorMediaType.V2_JSON)));
        return converter;
    }

to your client applications, the actuator endpoints are serialized not with the "global" object mapper and thus are not affected by the SNAKE_CASE naming.

[geniusit]

I can't make it work. When I add your piece of code then my property-naming-strategy: SNAKE_CASE is ignored.
So all my WS returns JSON in CamelCase and this is not what I want. I want everything in SNAKE_CASE except /actuator in CAMEL_CASE to make SBA works

[geniusit]

In your piece of code, i can't see where you tell that Actuator endoints must be CAMEL_CASE?
I think that I miss understood what you are doing.
Could you help to make my application work in SNAKE_CASE and have all my actuators endpoints working with Spring Boot Admin? Thank you

[joshiste]

I just needed this myself. This is my approach to serialize the actuator endpoints using the "default" object mapper and everything else with a custom config.

```
@Bean
@Order(0)
public MappingJackson2HttpMessageConverter actuatorJacksonHttpMessageConverter(Jackson2ObjectMapperBuilder builder) {
var converter = new MappingJackson2HttpMessageConverter(builder.build()) {
@Override
protected boolean canWrite(MediaType mediaType) {
//only exact matches
if (mediaType == null) {
return false;
}
return super.canWrite(mediaType);
}
};
converter.setSupportedMediaTypes(MediaType.parseMediaTypes(List.of(
ActuatorMediaType.V1_JSON,
ActuatorMediaType.V2_JSON,
ActuatorMediaType.V3_JSON
)));
return converter;
}

@Bean
@Order(Ordered.LOWEST_PRECEDENCE)
MappingJackson2HttpMessageConverter defaultJackson2HttpMessageConverter(Jackson2ObjectMapperBuilder builder) {
    builder.serializationInclusion(JsonInclude.Include.NON_NULL).propertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);
    return new MappingJackson2HttpMessageConverter(builder.build());
}

```