README.md

Sample Quiz REST Api

This is our Quiz REST Api implementation using Mule's APIKit router and RAML 1.0 definition.

Model and distributed database

Quiz entity (conveniently annotated for SQL). Take a look to org.hawkore.samples.api.quiz.entities.Quiz for more details:

• id: Unique identifier (quizCache key).
• email: Surveyed email.
• yes: a YES response.
• no: a NO response.
• na: a Non Answered Quiz.
• qts: The timestamp when a Quiz was received by an Api Node.
• pts: The timestamp when a Quiz was processed by a Worker node.
• apiIp: the Api Node IP that received the Quiz.
• workerIp: the Worker Node IP that processed the Quiz.

Quizzes will be stored into an Apache Ignite distributed Cache (quizCache), so, to enable SQL over this cache just configure cache to take care of this entity as an SQL Query Entity, just add tuple (java.lang.Long, org.hawkore.samples.api.quiz.entities.Quiz) into indexedTypes property - array of tuples (key type , value type) -:

<bean name="quiz-cache" id="quiz-cache" class="org.apache.ignite.configuration.CacheConfiguration">
    <property name="name" value="quizCache" />
    <property name="cacheMode" value="PARTITIONED" />
    <property name="indexedTypes">
        <array>
            <value>java.lang.Long</value>
            <value>org.hawkore.samples.api.quiz.entities.Quiz</value>
        </array>
    </property>
</bean>

Api operations:

Our REST Api implements below operations:

• Send a new Quiz (POST /api/quiz)
• List Quizzes (GET /api/quiz)
• Clear all quizzes and stats (DELETE /api/quiz)
• Retrieve global stats (GET /api/quiz/stats)

Send a new Quiz (POST /api/quiz)

Every received Quiz (POST request) by our REST API will be enqueued into an Apache Ignite Queue to perform distributed data processing by Workers (see mule-worker-app).

Mule flow to acquire Quizzes from HTTP POST request (/api/quiz) and publish them to a distributed Queue:

List Quizzes

As simple as query the distributed database (quizCache) using SQL (DataSense enabled):

Clear all quizzes and stats

It will delete all data stored in distributed quiz's cache (quizCache) and reset all distributed atomic Longs to 0 (global stats).

Retrieve global stats

Retrieve global stats (distributed atomic Longs) as JSON:

{
	"totalYes": 0,
	"totalNo": 0,
	"totalNa": 0,
	"totalReceived": 0,
	"totalProcessed": 0,
	"totalDuplicated": 0
}

Ignite Configuration for Kubernetes

Configure IP finder on ignite-config.xml as org.apache.ignite.spi.discovery.tcp.ipfinder.kubernetes.TcpDiscoveryKubernetesIpFinder with the kubernetes service name to find server nodes and the namespace.

 <bean id="ignite-config" class="org.apache.ignite.configuration.IgniteConfiguration">
    ...

    <!-- Explicitly configure TCP discovery SPI -->
    <property name="discoverySpi">
      <bean class="org.apache.ignite.spi.discovery.tcp.TcpDiscoverySpi">
        <property name="ipFinder">
          <!--
          Enables Kubernetes IP finder and set namespace and service name (cluster) to find SERVER nodes.
          -->
          <bean class="org.apache.ignite.spi.discovery.tcp.ipfinder.kubernetes.TcpDiscoveryKubernetesIpFinder">
            <property name="shared" value="true" />
            <property name="namespace" value="my-mule4-stack" />
            <property name="serviceName" value="ignite-cluster-one-service" />
          </bean>
        </property>
      </bean>
    </property>

    ...
</bean>

Kubernetes artifacts

• Namespace my-mule4-stack, service ignite-cluster-one-service and service mule-api-app-service for discovery, spring management and load balancing are defined in k8s configuration yaml for mandatory artifacts
• Will be started as a micro-service using Spring Boot Mule 4 Runtime CE docker image, see statefulSet configuration yaml for REST Api

Build Mule application

Build application:

mvn clean package