Mensagens baseadas na nuvem do Red Hat OpenShift usando o Quarkus e o AMQ Online

Quarkus app

Gerador de pedidos

@ApplicationScoped
public class OrderGenerator {
 
    private int orderId = 1;
 
    @Outgoing("orders")
    public Flowable<Integer> generate() {
        return Flowable.interval(5, TimeUnit.SECONDS)
        .map(tick -> orderId++);
    }
}

Manipulador de pedidos

@ApplicationScoped
public class OrderProcessor {
    @Incoming("orders")
    @Outgoing("confirmations")
    public Integer process(Integer order) {
        //       <img draggable="false" class="emoji" alt=":-)" src="https://s.w.org/images/core/emoji/11.2.0/svg/1f642.svg">
        return order * 2;
    }
}

Recursos de confirmação

@Path("/confirmations")
public class ConfirmationResource {
 
    @Inject
    @Stream("confirmations") Publisher<Integer> orders;
 
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String hello() {
        return "hello";
    }
 
 
    @GET
    @Path("/stream")
    @Produces(MediaType.SERVER_SENT_EVENTS)
    public Publisher<Integer> stream() {
        return orders;
    }
}

Costumização

Conectores

mp.messaging.outgoing.orders.connector=smallrye-amqp
mp.messaging.incoming.orders.connector=smallrye-amqp

Endpoint AMQP

spec:
  template:
    spec:
      containers:
      - env:
        - name: AMQP_HOST
          valueFrom:
            configMapKeyRef:
              name: quarkus-config
              key: service.host
        - name: AMQP_PORT
          valueFrom:
            configMapKeyRef:
              name: quarkus-config
              key: service.port.amqp

Credenciais

public class MessagingCredentialsConfigSource implements ConfigSource {
    private static final Set<String> propertyNames;
 
    static {
        propertyNames = new HashSet<>();
        propertyNames.add("amqp-username");
        propertyNames.add("amqp-password");
    }
 
    @Override
    public Set<String> getPropertyNames() {
        return propertyNames;
    }
 
    @Override
    public Map<String, String> getProperties() {
        try {
            Map<String, String> properties = new HashMap<>();
            properties.put("amqp-username", "@@serviceaccount@@");
            properties.put("amqp-password", readTokenFromFile());
            return properties;
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }
 
    @Override
    public String getValue(String key) {
        if ("amqp-username".equals(key)) {
            return "@@serviceaccount@@";
        }
        if ("amqp-password".equals(key)) {
            try {
                return readTokenFromFile();
            } catch (IOException e) {
                throw new UncheckedIOException(e);
            }
        }
        return null;
    }
 
    @Override
    public String getName() {
        return "messaging-credentials-config";
    }
 
    private static String readTokenFromFile() throws IOException {
        return new String(Files.readAllBytes(Paths.get("/var/run/secrets/kubernetes.io/serviceaccount/token")), StandardCharsets.UTF_8);
    }
}

Montagem e implantação do aplicativo

git clone https://github.com/EnMasseProject/enmasse-example-clients
cd enmasse-example-clients/quarkus-example-client
oc new-project myapp
mvn -Pnative -Dfabric8.mode=openshift -Dfabric8.build.strategy=docker package fabric8:build fabric8:resource fabric8:apply

Configuração de mensagens

Espaço de endereço

apiVersion: enmasse.io/v1beta1
kind: AddressSpace
metadata:
  name: quarkus-example
spec:
  type: brokered
  plan: brokered-single-broker
  endpoints:
  - name: messaging
    service: messaging
    exports:
    - name: quarkus-config
      kind: configmap

Endereços

apiVersion: enmasse.io/v1beta1
kind: Address
metadata:
  name: quarkus-example.orders
spec:
  address: orders
  type: queue
  plan: brokered-queue

Usuário de mensagens

apiVersion: user.enmasse.io/v1beta1
kind: MessagingUser
metadata:
  name: quarkus-example.app
spec:
  username: system:serviceaccount:myapp:default
  authentication:
    type: serviceaccount
  authorization:
  - operations: ["send", "recv"]
    addresses: ["orders"]

Permissões para personalizar o aplicativo

---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: quarkus-config
spec:
  rules:
  - apiGroups: [ "" ]
    resources: [ "configmaps" ]
    verbs: [ "create" ]
  - apiGroups: [ "" ]
    resources: [ "configmaps" ]
    resourceNames: [ "quarkus-config" ]
    verbs: [ "get", "update", "patch" ]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: quarkus-config
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: quarkus-config
subjects:
- kind: ServiceAccount
  name: address-space-controller
  namespace: amq-online-infra

Como aplicar configurações

cd enmasse-example-clients/quarkus-example-client
oc project myapp
oc apply -f src/main/resources/k8s/addressspace
oc apply -f src/main/resources/k8s/address

Verificação de aplicativo

until [[ `oc get address quarkus-example.prices -o jsonpath='{.status.phase}'` == "Active" ]]; do echo "Not yet ready"; sleep 5; done

echo "http://$(oc get route quarkus-example-client -o jsonpath='{.spec.host}')/prices.html"

Resumir