An introduction to Microservices - 7.3

The Audit Service will listen to a JMS queue and will simply log the message on the console.

1. Create a new route and place the components as displayed below.
   You have cMQConnectionFactory, cJMS, cProcessor and cMessagingEndpoint components in the designer canvas.

   

   You need to configure the Broker URL of the MQ Connection Factory to your Active MQ Broker Server which is tcp://localhost:61616, in this example.

   You are running a local instance of ActiveMQ which is part of Talend ESB. The cJMS component is configured to listen the queue audit.

2. Use the cProcessor component to enrich the camel Exchange.
   

   String audit = "Audit Message Received: "+ exchange.getIn().getBody(String.class);                    

3. Configure the cMessagingEndpoint component as a Camel Log component.
   

   "log:AuditLog?showAll=true&multiline=true"

   The Audit Service will now listen to the Queue audit and will log it on the console. This message can be saved to the database for auditing purposes. You can run the route to verify that it compiles and runs correctly at this point.

4. To export the Audit Service as a Microservice, in the Deployment tab of the Job view, select RouteMicroservice in the Build Type list. Save the Route.
   
5. In the Repository tree view, right click the Route and select Build Route.
   
6. The build type is set to ESB Microservices (Spring Boot). Click Finish to export the Route.
   
7. To run Microservice, locate the 'Audit****.jar file where you have saved it and run it using java -jar command.
   

   java -jar AuditService_0.1.jar --server.port=8066  

   By default, the monitoring port is 8605 which can be overwritten by passing simple parameter --server.port=port to the java command starting the service.

   This port is used to monitor the status of the service and is discussed in next section.

   The microservice can be exported as a zip file that contains the Windows and Linux scripts (.bat and .sh) to help with starting up the microservice. This functionality is available from Talend 6.3.1.

   

1. Place the following components as shown in the screenshot below:

   • cBeanRegister - cMQConnectionFactory - cConfig

   • cREST - cSetBody - cWireTap

   • cSEDA - cJavaDSLProcessor - cJMS - cJavaDSLProcessor

   
2. Configure the cBeanRegister component to customers as a Bean Id. In the code section, we are going to populate some random data.
   

   beans.Customers customers = new beans.Customers();
                           beans.Customer customer = new beans.Customer();
                           customer.setFirstName(TalendDataGenerator.getFirstName());
                           customer.setLastName(TalendDataGenerator.getLastName());
                           customer.setCity(TalendDataGenerator.getUsCity());
                           customers.addCustomer(customer);
                           customer = new beans.Customer();
                           customer.setFirstName(TalendDataGenerator.getFirstName());
                           customer.setLastName(TalendDataGenerator.getLastName());
                           customer.setCity(TalendDataGenerator.getUsCity());
                           customers.addCustomer(customer);
                           beanInstance = customers;    

   You have created two Beans namely Customer and Customers.

   The following is the code for the Customers Bean:

   @XmlRootElement
   public class Customers {
                       ArrayList<Customer> customers = new ArrayList<Customer>();
                       @XmlElement
                       public ArrayList<Customer> getCustomers() {
                                           return customers;
                       }
                        public void setCustomers(ArrayList<Customer> customers) {		
                                   this.customers = customers;
                       }
                         public void addCustomer(Customer customer) {
                                   if (this.customers == null) {
                                            customers = new ArrayList<Customer>();
                                   }
                                   this.getCustomers().add(customer);
                                   }
                                   }

   and the following code is for the Customer Bean:

   @XmlRootElement
   @XmlType(propOrder = { "firstName", "lastName", "city" })
   public class Customer {
          private String firstName;
          private String lastName;
          private String city;
   @XmlElement(name = "firstName")
   public String getFirstName() {
          return firstName;
          }
   public void setFirstName(String firstName) {
           this.firstName = firstName;
                           }
   @XmlElement(name = "lastName")
   public String getLastName() {
          return lastName;
   }
   public void setLastName(String lastName) {
           this.lastName = lastName;
                           }
   @XmlElement(name = "city")
   public String getCity() {
           return city;
   }
   public void setCity(String city) {
     this.city = city;
     }
   }

3. We need to convert the data to XML format. Configure a cConfig component to include the required jar files and instantiate the Jaxb context.
   

   import org.apache.camel.spi.DataFormat; 
   import org.apache.camel.converter.jaxb.JaxbDataFormat;
   import javax.xml.bind.*;
   
   JAXBContext jc = JAXBContext.newInstance( beans.Customers.class);
   DataFormat jaxb = new JaxbDataFormat(jc);

4. Configure the cREST component to listen on the endpoint http://127.0.0.1:8041/services/customers. Select the option Produces JSON in Rest API Mapping.
5. Configure the cSetBody component to call the customers Bean as shown in the screenshot below.
   
6. Connect the cSetBody to the cWireTap component to send an audit message to the seda component. Configure the cWireTap with URI seda:toAudit.
7. Connect the cSEDA component with the cJavaDSLProcessor and configure it with the code .marshal(jaxb) as shown below. Jaxb is the DataFormat handler you already defined in the cConfig component.
   
8. Connect with the cJMS and again with the cJavaDSLProcessor with Code .end(). Configure the Queue name audit.
   
9. Run the Route and test it with a browser. You should get a customer list in JSON format as shown below.
   

   Now instead of deploying service to a Talend Runtime server, we will export it as a microservice.

10. Right click on the route and select Build Route.
    
11. In Build type, select ESB Microservices (Spring Boot) and click Finish.
    
12. Locate the jar file and run it with a java command.
    

    Java -jar CustomerProducer***.jar 

In this example, you will consume a rest service to demonstrate how to call a rest service.

1. Place the cTimer, cREST and cLog components on the studio canvas.
2. Configure the cREST component to call the service you just executed as a microservice.
   
3. Just like before, build and export the service as a microservice. Start the service by calling the java -Jar command. The service will log customer data on consumer console as shown below.
   

   As the consumer service calls the provider service, the Audit service will log an audit message on the console.