stakater-nordmart-catalog

Overview

A maven spring boot catalog application for the product catalog and product information retrieval.

User scenarios

Product operations

Service has API for CRUD operations for products:

• Create (POST request against "/api/products/" URL) - service saves entity into the database and also sends product create command to products topic of Kafka. Search service consumes this message and store product into Elasticsearch. Product can be searched via Nordmart Web after that.
• Update (PUT request against "/api/products/" URL) - service update entity into the database and also sends product update command to products topic of Kafka. Search service consumes this message and updates product in Elasticsearch. Updated product can be searched via Nordmart Web after that.
• Delete (DELETE request against "/api/products/{itemaId}" URL) - service deletes entity from the database and also sends product delete command to products topic of Kafka. Search service consumes this message and deletes product from Elasticsearch. Product no longer available for search via Nordmart Web after that.
• Read (GET request against "/api/products/{itemaId}" URL) - service exposes API to get product by itemId. Data about product is got from Database.

Dependencies

It requires following things to be installed:

• Java: ^8.0
• Maven

Deployment strategy

Local deployment

To run the application locally use the command given below:

mvn spring-boot:run

Docker

To deploy app inside a docker container

• Create a network if it doesn't already exist by executing

  docker network create --driver bridge nordmart-apps

• Build jar file of the app by executing command given below:

  mvn clean package

• Next build the image using

  docker build -t catalog .

• Finally run the image by executing

  docker run -d --name catalog --network nordmart-apps -p 8080:8080 catalog

Helm Charts

Pre-requisites

Helm operator needs to to be running inside the cluster. Helm operator is deployed by Stakater Global Stack, deployment guidelines are provided in this link

Helm chart deployment

To create helm release of this application using the command given below:

kubectl apply -f helm-release.yaml -n

Prometheus

Prometheus Dependencies

The following dependencies are needed to expose micrometer and application metrics

<dependencies>
    <!-- For micrometer support -->
    <dependency>
        <groupId>io.micrometer</groupId>
        <artifactId>micrometer-core</artifactId>
        <version>1.1.4</version>
    </dependency>
    <dependency>
        <groupId>io.micrometer</groupId>
        <artifactId>micrometer-registry-prometheus</artifactId>
        <version>1.1.4</version>
    </dependency>
</dependencies>

Configuration

Startup configuration

By default, application synchronizes state of the database on the startup with Kafka. This is helpful during testing. You can disable it by setting false to the kafka.sync.onstartup property.

Kafka configuration

• kafka.bootstrapAddress - address of the Kafka broker
• kafka.products.topic - name of the topic where products will be send on CRU operations

Micrometer configuration

Add the following properties to application.properties to expose the micrometer endpoint.

management.endpoint.metrics.enabled=true
management.endpoints.web.exposure.include=*
management.endpoint.prometheus.enabled=true
management.metrics.export.prometheus.enabled=true

Adding micrometer registry

Add the MeterRegistry bean to your spring boot application by adding the follwoing snippet to your SpringBootApplication class.

    @Bean
    MeterRegistryCustomizer<MeterRegistry> metricsCommonTags() {
        return registry -> registry.config().commonTags("application", "common-service");
    }

This will help you create custom metrics within the application

Counter

To count the number of times an operation has been performed, just create a io.micrometer.core.instrument.Counter variable by doing

Counter.builder("count_metric_name").description("Description of metric").register(meterRegistry);

Time Measurement

To add metrics that keeps track of processing time taken by a piece of code, follow the following snippet:

private final Timer timer = Timer.builder("metricsname").tag("tagKey", "tagValue").register(meterRegistry);
long start = System.nanoTime();
...your code here
timer.record(System.nanoTime() - start, TimeUnit.NANOSECONDS);

Gauge

A gauge is a handle to get the current value. Typical examples for gauges would be the size of a collection or map. To create a gauge metric just do

AtomicInteger myCount = meterRegistry.gauge("gauge_value", new AtomicInteger(0));

and then you can just set the value as it changes using

myCount.set(myList.size());

Monitoring

Dasbhoards given below can be used to monitor application by configuring them in Monitoring stack. If monitoring stack is not already configured use guidelines given in this link to configure it.

• Catalog service metrics dashboard can be configured using this config.