Spring Boot Actuator 2.x #WriteOperation with an object as parameter - spring-boot

Question

What I try to achieve:
I want to create an endpoint that is accessible from web and jmx with an action that takes an object as a parameter
here is a simple example:
pom.xml
....
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.0.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.jolokia</groupId>
<artifactId>jolokia-core</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
The Object class:
#Data
#NoArgsConstructor
#AllArgsConstructor
public class Dog {
protected String name;
protected int age;
}
The endpoint class
#Component
#Endpoint(id = "dogs")
#Slf4j
public class EndpointDogsExperiment {
protected List<Dog> dogs = new ArrayList<>();
public EndpointDogsExperiment() {
dogs.add(new Dog("dog0", 5));
dogs.add(new Dog("dog1", 7));
log.debug("dogs created {}", dogs.toString());
}
#WriteOperation
public List<Dog> addDog(Dog dog) {
log.debug("adding a dog \n{}", dog );
dogs.add(dog);
return dogs;
}
}
the problem:
how do I "call" this operation
when I try HTTP POST with
/actuator/dogs
and body
{"dog":{"name":"aaaa", "age":33}}
client gets
Response:
status: 400
date: Sat, 31 Mar 2018 14:59:41 GMT
connection: close
transfer-encoding: chunked
content-type: application/vnd.spring-boot.actuator.v2+json;charset=UTF-8
{"timestamp":"2018-03-31T14:59:41.778+0000","status":400,"error":"Bad Request","message":"No message available","path":"/actuator/dogs"}
and server log say
2018-03-31 17:59:41.766 WARN 12828 --- [nio-8081-exec-1] .w.s.m.s.DefaultHandlerExceptionResolver : Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize instance of java.lang.String out of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of java.lang.String out of START_OBJECT token
at [Source: (PushbackInputStream); line: 1, column: 8] (through reference chain: java.util.LinkedHashMap["dog"])
I have tried to create a #WriteOperation that has a String parameter and then
HTTP POST body
{"paramName":"StringParamValue"}
works ok
why is it?
Thanks!

Answer 1

Endpoint operations don’t support complex input such as your Dog type. You could, however, consume separate name and age parameters and create the Dog in the operation’s implementation:
#WriteOperation
public List<Dog> addDog(String name, int age) {
Dog dog = new Dog(name, age);
log.debug("adding a dog \n{}", dog );
dogs.add(dog);
return dogs;
}
You can learn more in Spring Boot's reference documentation.

Answer 2

Just use the #RestControllerEndpoint(id = "features") class level annotation.
On the methods you then have to use your regular #PostMapping annotation and it should work