MicroProfile GraphQL Example

This is an example of the MicroProfile GraphQL API using the SmallRye Implementation. It's done as part of these blog posts:

and these presentations:

Upcoming: Global Summit for Java devs'20
Quarkus Insights
#OffTheChain
joziJUG
SouJava
DevConf.cz
Java cloud conference

The services are exposed with both REST and GraphQL for comparison.

Person example

This example expose person data as well as scores that the person got for certain activities.

Running in Quarkus

(generate from https://code.quarkus.io/)

cd quarkus-example
mvn clean install quarkus:dev

Running in Wildfly

cd wildfly-example
mvn clean install wildfly:run

This will start the application on port 8080.

Testing

Go to http://localhost:8080 to test the application.

Click on the 'REST' link to open Swagger UI to test the JAX-RS services.
Click on the 'GraphQL' link to open GraphiQL UI to test the MicroProfile GraphQL service.

To stop the application, ctrl-c in the maven session.

Examples

See the model in the JavaDoc (target/apidocs/index.html)

Demo 1 : MicroProfile GraphQL vs JAX-RS

REST

Schema: http://localhost:8080/openapi

curl -X GET "http://localhost:8080/rest/profile/1" -H  "accept: application/json"

GraphQL

Schema: http://localhost:8080/graphql/schema.graphql

{
  person(id:1){
    names
    surname
  }
}

Demo 2: Stitching

{
  person(id:1){
    names
    surname
    scores{
      name
      value
    }
  }
}

in the log file:

======= Getting person [1] =======
======= Getting scores [512-46-5065] =======

without score

{
  person(id:1){
    names
    surname
  }
}

in the log file:

======= Getting person [1] =======

Demo 3: More than one request

{
  person1:person(id:1){
    surname
    scores{
      name
      value
    }
  }
  person2:person(id:2){
    surname
  }
}

or more than one query:

@Query
public Integer getRandomNumber(long seed){
    Random random = new Random(seed);
    return random.nextInt();
}

{
  person1:person(id:1){
    surname
    scores{
      name
      value
    }
  }
  randomId:randomNumber(seed:11)
}

Demo 4: Collections

{
  people {
    surname
  }
}

Demo 5: JsonB Annotations support

{
  person(id:1){
     surname
     birthDate
  }
}

Demo 6: DefaultValue

@Query
public List<Person> getPersonsWithSurname(
        @DefaultValue("Doyle") String surname) {
    return personService.getPeopleWithSurname(surname);
}

Providing a parameter

{
  personsWithSurname(surname:"Hyatt") {
    names
  }
}

Uing the default

{
  personsWithSurname {
    names
  }
}

Demo 7: Errors and partial responses

Validation Errors

{
  person(id:1){
     surname
     scores{
      thisDoesNotExist
    }
  }
}

Partial results

{
  person(id:1){
     surname
     scores{
      name
      value
    }
  }
}

Demo 8: Metrics and Tracing

Servers

This will be specific to your setup. For me:

Start Prometheus:

cd /opt/Metrics/prometheus-2.19.2.linux-amd64
./prometheus --config.file=prometheus.yml

(prometheus.yml is in the root folder)

Start Grafana:

sudo systemctl start grafana-server

(grafana.json is in the root folder)

Start Jaeger:

docker run -p 5775:5775/udp -p 6831:6831/udp -p 6832:6832/udp -p 5778:5778 -p 16686:16686 -p 14268:14268 jaegertracing/all-in-one:latest

Metrics

@Timed(name = "personTimer", description = "How long does it take to get a Person.", unit = MetricUnits.NANOSECONDS)
@Counted(name = "personCount", description = "How many times did we ask for Person.")

Grafana Dashboard

Tracing

Jaeger Dashboard

Demo 9: Security

@RolesAllowed("admin")

Demo 10: Bean validation

@Query
public Integer getRandomNumber(@Min(10) long seed){
    Random random = new Random(seed);
    return random.nextInt();
}

{
  randomNumber(seed:9)
}

Demo 11: Mutations

    @Mutation
    public Person updatePerson(Person person){
        return personService.updateOrCreate(person);
    }
    
    @Mutation
    public Person deletePerson(Long id){
        return personService.delete(id);
    }

Create

mutation CreatePerson{
  updatePerson(person : 
    {
      names: "Phillip"
    }
  ){
    id
    names
    surname
    profilePictures
    website
  }
}

Update

(using the generated id)

mutation UpdatePerson{
  updatePerson(person : 
    {
      id: 11, 
      names:"Phillip",
      surname: "Kruger", 
      profilePictures: [
        "https://pbs.twimg.com/profile_images/1170690050524405762/I8KJ_hF4_400x400.jpg"
      ],
      website: "http://www.phillip-kruger.com"
    }){
    id
    names
    surname
    profilePictures
    website
  }
}

Delete

(using the id)

mutation DeletePerson{
  deletePerson(id :11){
    id
    surname
  }
}

Demo 12: Context (Experimental)

quarkus.hibernate-orm.log.sql=true

@Inject
Context context;

JsonArray selectedFields = context.getSelectedFields();
System.out.println("selectedFields [" + selectedFields +"]");

{
  people{
    surname
  }
}

Demo 13: Client (Future)