{"id":829,"date":"2020-03-30T15:00:00","date_gmt":"2020-03-30T15:00:00","guid":{"rendered":"http:\/\/bullyrooks.com\/index.php\/2020\/04\/10\/simple-spring-boot-service-to-kubernetes-application-step-15-34e1bba8351b\/"},"modified":"2021-02-04T02:05:47","modified_gmt":"2021-02-04T02:05:47","slug":"simple-spring-boot-service-to-kubernetes-application-step-15-34e1bba8351b","status":"publish","type":"post","link":"https:\/\/bullyrooks.com\/index.php\/2020\/03\/30\/simple-spring-boot-service-to-kubernetes-application-step-15-34e1bba8351b\/","title":{"rendered":"Messaging and Event Driven Design"},"content":{"rendered":"\n

In order publish messages, we need a message broker and add some logic to use the message broker. We\u2019re going to use a cloud based SaaS service as a message broker and use spring cloud stream to interact with it.<\/p>\n\n\n\n

Setup the Message Broker<\/h3>\n\n\n\n

We\u2019ll need a message broker in order to publish and we can stand up a free one at cloudamqp<\/a>. Go ahead and register an account. Once that is done, create a new instance. We\u2019re going to create a free instance called medium<\/code> in whatever region you want. When that is done, click on the instance to get the details. We\u2019re going to need the host, user and password from here.<\/p>\n\n\n\n

Write the Publisher Logic<\/h3>\n\n\n\n

Create a new package called com.brianrook.medium.customer.messaging<\/code> and in that package create 2 more sub packages for mapper <\/code>and message<\/code>. First create the message payload in message <\/code>using a class called CustomerCreatedMessage<\/code>:<\/p>\n\n\n\n

package com.brianrook.medium.customer.messaging.message;\n\nimport lombok.Data;\n\n@Data\npublic class CustomerCreatedMessage {\n    private Long customerId;\n    private String firstName;\n    private String lastName;\n    private String phoneNumber;\n    private String email;\n}<\/code><\/pre>\n\n\n\n
Create a mapper interface under mapper<\/code> called CustomerMessageMapper <\/code>with this content:<\/p>\n\n\n\n
package com.brianrook.medium.customer.messaging.mapper;\n\nimport com.brianrook.medium.customer.messaging.message.CustomerCreatedMessage;\nimport com.brianrook.medium.customer.service.model.Customer;\nimport org.mapstruct.Mapper;\nimport org.mapstruct.factory.Mappers;\n\n@Mapper\npublic interface CustomerMessageMapper {\n    CustomerMessageMapper INSTANCE <\/em>= Mappers.getMapper<\/em>(CustomerMessageMapper.class);\n\n    CustomerCreatedMessage customerToCustomerCreatedMessage(Customer customer);\n}<\/code><\/pre>\n\n\n\n
in com.brianrook.medium.customer.config<\/code> createCustomerCreateBinding<\/code>:<\/p>\n\n\n\n
package com.brianrook.medium.customer.messaging;\n\nimport org.springframework.cloud.stream.annotation.Output;\nimport org.springframework.messaging.MessageChannel;\n\npublic interface CustomerCreateBinding {\n\n    @Output(\"customerCreateChannel\")\n    MessageChannel customerCreate();\n}<\/code><\/pre>\n\n\n\n
and in com.brianrook.medium.customer.messaging <\/code>create CustomerCreatePublisher<\/code><\/p>\n\n\n\n
package com.brianrook.medium.customer.messaging;\n\nimport com.brianrook.medium.customer.messaging.mapper.CustomerMessageMapper;\nimport com.brianrook.medium.customer.messaging.message.CustomerCreatedMessage;\nimport com.brianrook.medium.customer.service.model.Customer;\nimport org.springframework.beans.factory.annotation.Autowired;\nimport org.springframework.cloud.stream.annotation.EnableBinding;\nimport org.springframework.messaging.Message;\nimport org.springframework.messaging.support.MessageBuilder;\nimport org.springframework.stereotype.Component;\n\n@Component\n@EnableBinding(CustomerCreateBinding.class)\npublic class CustomerCreatePublisher {\n\n    @Autowired\n    CustomerCreateBinding customerCreateBinding;\n\n    public void publishCustomerCreate(Customer customer) {\n        CustomerCreatedMessage customerMessage = CustomerMessageMapper.INSTANCE<\/em>.customerToCustomerCreatedMessage(customer);\n        Message<CustomerCreatedMessage> msg = MessageBuilder.withPayload<\/em>(customerMessage).build();\n\n        customerCreateBinding.customerCreate().send(msg);\n    }\n}<\/code><\/pre>\n\n\n\n
and hook it into our service CustomerService:<\/p>\n\n\n\n
...<\/pre>\n\n\n\n
@Autowired\nCustomerCreatePublisher customerCreatePublisher;<\/code><\/pre>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
public Customer saveCustomer(Customer customer) {\n    if (customerExists(customer))\n    {\n        throw new CreateCustomerException(String.format<\/em>(\"customer with email: %s already exists\", customer.getEmail()));\n    }\n    Customer savedCustomer = persistCustomer(customer);\n    customerCreatePublisher.publishCustomerCreate(savedCustomer);\n\n    return savedCustomer;\n}<\/code><\/pre>\n\n\n\n
And finally we\u2019ll need to configure our application, add this configuration to application.yaml<\/code>:<\/p>\n\n\n\n
spring:<\/code><\/pre>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
  cloud:\n    stream:\n      bindings:\n        output:\n          destination: queue.customer.create\n          content-type: application\/json\n  rabbitmq:\n    addresses: amqp:\/\/shrimp.rmq.cloudamqp.com\/c***j<\/code><\/pre>\n\n\n\n
Here we\u2019re telling spring boot to create a rabbit destination on the instance and where to connect to. Make sure to strip out the username and password from the url and replace with your own instance name.<\/p><\/blockquote>\n\n\n\n
We also need to add the rabbit binder libraries to the pom.xml<\/code><\/p>\n\n\n\n
<dependency>\n   <groupId>org.springframework.cloud<\/groupId>\n   <artifactId>spring-cloud-starter-stream-rabbit<\/artifactId>\n<\/dependency>\n<dependency>\n   <groupId>org.springframework.cloud<\/groupId>\n   <artifactId>spring-cloud-stream-binder-rabbit<\/artifactId>\n<\/dependency><\/code><\/pre>\n\n\n\n
Testing<\/h3>\n\n\n\n
Update CustomerControllerTest<\/code> to test that we can publish this message.<\/p>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
@Autowired\nMessageCollector messageCollector;\n@Autowired\nAppointmentCreateBinding appointmentCreateBinding;<\/code><\/pre>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
@Test\npublic void testAddCustomerSuccess() throws URISyntaxException, JsonProcessingException {<\/code><\/pre>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
    \/\/validate AMQP\n    Message<String> publishedMessage = (Message<String>)messageCollector\n            .forChannel(customerCreateBinding.customerCreate())\n            .poll();\nassertThat<\/em>(publishedMessage).isNotNull();\n    ObjectMapper om = new ObjectMapper().registerModule(new JavaTimeModule());\n\n    CustomerCreatedMessage appointmentMessage = om.readValue(\n            publishedMessage.getPayload(),\n            CustomerCreatedMessage.class);\nassertThat<\/em>(appointmentMessage.getCustomerId()).isGreaterThan(0l);\n}<\/code><\/pre>\n\n\n\n
...<\/pre>\n\n\n\n
@Test\npublic void testAddCustomerConflict() throws URISyntaxException {<\/code><\/pre>\n\n\n\n
...\n\n    \/\/validate AMQP\nassertThat<\/em>(messageCollector\n            .forChannel(customerCreateBinding.customerCreate())\n            .isEmpty()).isTrue();\n}<\/code><\/pre>\n\n\n\n
Here we\u2019re using the spring application context to hook into the spring bindings used to talk to our AMQP broker. We\u2019re essentially wiring in before the logic to publish a message is executed and pulling the messages out of the pipeline before they get sent. We can also confirm that messages are not sent in the case of errors.<\/p><\/blockquote>\n\n\n\n
We\u2019ve also added significant functionality so lets update our application version using semantic versioning. Update the pom.xml<\/code>:<\/p>\n\n\n\n
<groupId>com.brianrook.medium<\/groupId>\n<artifactId>medium-customer<\/artifactId>\n<version>0.1.0-SNAPSHOT<\/version>\n<name>medium-customer<\/name><\/code><\/pre>\n\n\n\n
I was also having trouble with the LoggingAspect <\/code>trying to log system actions on startup, so I changed the pointcut configuration to look like this, in order to limit what was visible to aspectj:<\/p>\n\n\n\n
@Around(\"within(com.brianrook.medium.customer.controller. .*) \" +\n        \"&& within(com.brianrook.medium.customer.service. .*) \" +\n        \"&& within(com.brianrook.medium.customer.messaging. .*) \" +\n        \"&& within(com.brianrook.medium.customer.dao. .*) ) \")<\/code><\/pre>\n\n\n\n
We can also startup the application locally if we add the following configuration to the application startup config:<\/p>\n\n\n\n
-Dspring.profiles.active=herokudb\n-Dspring.datasource.username=<db username>\n-Dspring.datasource.password=<db password>\n-Dspring.rabbitmq.username=<cloudamqp username>\n-Dspring.rabbitmq.password=<cloudamqp password><\/code><\/pre>\n\n\n\n
If we save a customer, we should be able to see a message published in the cloudamqp manager console.<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Kubernetes Configuration<\/h3>\n\n\n\n
This configuration is only valid for running locally for tests though. We need to configure our running application. We can do that by adding to our helm values.yaml<\/code> file and uploading another secrets file.<\/p>\n\n\n\n
values.yaml<\/p>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
content: |-\n  spring:<\/code><\/pre>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
    cloud:\n      stream:\n        bindings:\n          output:\n            destination: queue.customer.create\n            content-type: application\/json\n    rabbitmq:\n      addresses: amqp:\/\/shrimp.rmq.cloudamqp.com\/c***j<\/code><\/pre>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
secretsToEnv:<\/code><\/pre>\n\n\n\n
...<\/code><\/pre>\n\n\n\n
  - name: SPRING_RABBITMQ_PASSWORD\n    valueFrom:\n      secretKeyRef:\n        name: amqp-secrets\n        key: SPRING_RABBITMQ_PASSWORD\n  - name: SPRING_RABBITMQ_USERNAME\n    valueFrom:\n      secretKeyRef:\n        name: amqp-secrets\n        key: SPRING_RABBITMQ_USERNAME<\/code><\/pre>\n\n\n\n
Upload your secrets file<\/p>\n\n\n\n
kubectl create secret generic amqp-secrets --from-literal=SPRING_RABBITMQ_PASSWORD=<cloud amqp password> --from-literal=SPRING_RABBITMQ_USERNAME=<cloud amqp user\/vhost><\/code><\/pre>\n\n\n\n
Build and Commit<\/h3>\n\n\n\n
git checkout -b customer-updates\nmvn clean install\ngit add .\ngit commit -m \"new functionality and publishing\"\ngit push --set-upstream origin customer-updates\ngit checkout master\ngit merge customer-updates\ngit push<\/code><\/pre>\n\n\n\n
Now lets let the build pipeline generate a new chart version and use the updated chart to deploy to minikube<\/p>\n\n\n\n
After the build completes go to the helm chart registry and locate the latest version<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
In this case we want 5<\/p>\n\n\n\n
take a look at helm to see what is currently deployed<\/p>\n\n\n\n
$ helm list\nNAME    NAMESPACE       REVISION        UPDATED                                 STATUS          CHART                   APP VERSION\nmedium  default         2               2020-04-04 13:56:58.2124564 -0600 MDT   deployed        medium-customer-3       0.0.1<\/code><\/pre>\n\n\n\n
update the repositories<\/p>\n\n\n\n
helm repo update<\/code><\/pre>\n\n\n\n
now list our repo contents<\/p>\n\n\n\n
$ helm search repo codefresh\nNAME                            CHART VERSION   APP VERSION     DESCRIPTION\ncodefresh\/medium-customer       5               0.0.1           A Helm chart for Kubernetes<\/code><\/pre>\n\n\n\n
we can see that the chart versions match, so we pulled down the latest built version. Lets deploy it.<\/p>\n\n\n\n
helm upgrade medium codefresh\/medium-customer --version=5<\/code><\/pre>\n\n\n\n
we should be able to verify any of the new functionality we added<\/p>\n\n\n\n
GET \/customer\/all HTTP\/1.1\nHost: 172.17.144.73:30001\nContent-Type: application\/json\nContent-Type: text\/plain<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
\nIn order publish messages, we need a message broker and add some…\n<\/div>\n
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