Build a microservices architecture with Spring Boot and Spring Cloud

Developing a microservice architecture with Java and Spring Boot is quite popular these days. It’s definitely one of the most popular combinations in the Java ecosystem. If you need any proof, just look at all of the similar frameworks that have cropped up in the last few years: MicroProfile, Micronaut, and Quarkus, just to name a few.

Spring Boot provided a much-needed spark to the Spring ecosystem when it was first released in 2014. Instead of making Java developers configure all aspects of their Spring beans, it provided “starters” that contained pre-configured beans with the default settings. This led to less Java code, and also provided the ability to override the defaults via an file. Yes, there are many ways to modify the defaults in a Spring Boot application, but I’ll skip over that for now.

Java Microservices with Spring Cloud Config

Spring Cloud Config is a project that provides externalized configuration for distributed systems. Spring Cloud Config has server and client components. You can configure the server to read its configuration from the file system or a source code repository, like Git. On the client, you configure things in a bootstrap configuration file to get configuration data from the server. In a microservices environment, this provides an elegant way to configure all your microservices from a central location.

Today I’d like to show you how this works and demo it using one of the hippest microservice solutions I’ve ever worked with.

Use JHipster to Generate a Java Microservices Architecture

JHipster is a development platform to generate, develop, and deploy Spring Boot + { Angular or React or Vue } applications. In addition, it supports creating Spring based microservice architectures. In fact, if you create microservices projects and choose OAuth 2.0 / OIDC for authentication, you’ll be using code that’s very similar to the aforementioned example.

To use JHipster, you’ll need to have Node.js installed. You can also use, which is similar to

The most common way to install JHipster is using npm:

npm install -g generator-jhipster@6.0.1

You can run the command above without the version number to get the latest version of JHipster. If it’s 6.x, this tutorial should work, but I can’t guarantee it does.

In a terminal, create a directory to hold all the projects you’re about to create. For example, jhipster.

Create an apps.jh file in this directory and put the following code into it.

application {
  config {
    baseName gateway,
    packageName com.okta.developer.gateway,
    applicationType gateway,
    authenticationType oauth2,
    prodDatabaseType postgresql,
    serviceDiscoveryType eureka,
    testFrameworks [protractor]
  entities Blog, Post, Tag, Product

application {
  config {
    baseName blog,
    applicationType microservice,
    authenticationType oauth2,
    prodDatabaseType postgresql,
    serverPort 8081,
    serviceDiscoveryType eureka
  entities Blog, Post, Tag

application {
  config {
    baseName store,
    applicationType microservice,
    authenticationType oauth2,
    databaseType mongodb,
    devDatabaseType mongodb,
    prodDatabaseType mongodb,
    enableHibernateCache false,
    serverPort 8082,
    serviceDiscoveryType eureka
  entities Product

entity Blog {
  name String required minlength(3),
  handle String required minlength(2)

entity Post {
  title String required,
  content TextBlob required,
  date Instant required

entity Tag {
  name String required minlength(2)

entity Product {
  title String required,
  price BigDecimal required min(0),
  image ImageBlob

relationship ManyToOne {
  Blog{user(login)} to User,
  Post{blog(name)} to Blog

relationship ManyToMany {
  Post{tag(name)} to Tag{post}

paginate Post, Tag with infinite-scroll
paginate Product with pagination

microservice Product with store
microservice Blog, Post, Tag with blog

// will be created under 'docker-compose' folder
deployment {
  deploymentType docker-compose
  appsFolders [gateway, blog, store]
  dockerRepositoryName "jmicro"
  consoleOptions [zipkin]

You’ll want to change the dockerRepositoryName in the JDL above to use yourDocker Hubusername if you want to publish your containers. This is not a necessary step to complete this tutorial.

This code is JDL (JHipster Domain Language) and you can use it to define your app, its entities, and even deployment settings. You can learn more about JDL in JHipster’s JDL documentation. Below is a screenshot of JDL Studio, which can be used to edit JDL and see how entities related to each other.

microservices architecture patterns

The JDL you just put in apps.jh defines three applications:

  • gateway: a single entry point to your microservices, that will include the UI components.
  • blog: a blog service that talks to PostgreSQL.
  • store: a store service that uses MongoDB.

Run the following command to create these projects in your jhipster folder.

jhipster import-jdl apps.jh

This will create all three projects in parallel. You can watch the console recording below to see how it looks. The time it takes to create everything will depend on how fast your computer and internet are.

Create Docker Images for Microservice Apps

When the configuration is generated for Docker Compose, a warning is spat out to the console.

WARNING! Docker Compose configuration generated, but no Jib cache found
If you forgot to generate the Docker image for this application, please run:
To generate the missing Docker image(s), please run:
  ./mvnw -Pprod verify jib:dockerBuild in /Users/mraible/java-microservices-examples/jhipster/gateway
  ./mvnw -Pprod verify jib:dockerBuild in /Users/mraible/java-microservices-examples/jhipster/blog
  ./mvnw -Pprod verify jib:dockerBuild in /Users/mraible/java-microservices-examples/jhipster/store

To make it easier to create Docker images with one command, create an aggregator pom.xml in the jhipster root directory.

<project xmlns="" xmlns:xsi=""

Then “just jib it” using Jib.

mvn -Pprod verify

If you don’t have Maven installed, use brew install maven on a Mac, or see Maven’s installation docs.

[INFO] Skipping containerization because packaging is 'pom'...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] Gateway 0.0.1-SNAPSHOT ............................. SUCCESS [02:44 min]
[INFO] Blog 0.0.1-SNAPSHOT ................................ SUCCESS [ 34.391 s]
[INFO] Store 0.0.1-SNAPSHOT ............................... SUCCESS [ 28.589 s]
[INFO] jhipster-parent 1.0.0-SNAPSHOT ..................... SUCCESS [  1.096 s]
[INFO] ------------------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 03:49 min
[INFO] Finished at: 2019-05-17T07:44:39-06:00
[INFO] ------------------------------------------------------------------------
Execution time: 3 min. 50 s.

Run Your Java Microservices Stack with Docker Compose

Once everything has finished building, cd into the docker-compose directory and start all your containers.

cd docker-compose
docker-compose up -d

Remove the -d if you want to see all the logs in your current terminal window.

It will take several minutes to start all eight of your containers. You can use Kitematic to monitor their startup progress if you like.

Creating docker-compose_gateway-app_1                ... done
Creating docker-compose_gateway-postgresql_1         ... done
Creating docker-compose_blog-app_1                   ... done
Creating docker-compose_store-mongodb_1              ... done
Creating docker-compose_keycloak_1                   ... done
Creating docker-compose_blog-postgresql_1            ... done
Creating docker-compose_jhipster-registry_1          ... done
Creating docker-compose_store-app_1                  ... done

JHipster Registry for Service Discovery with Java Microservices

This microservices stack uses Eureka for service discovery, just like the bare-bones Spring Boot + Spring Cloud example. This was determined by the following line for each app in the JDL.

serviceDiscoveryType eureka

When you select eureka for service discovery, JHipster Registry is used. This application is very similar to Eureka Server, except it has an Angular UI and includes Spring Cloud Config, among other features.

JHipster also supports Hashicorp Consul for service discovery.

Because you chose OAuth 2.0/OIDC for authentication, you’ll need to create an entry in your hosts file (/etc/hosts on Linux/Mac, C:\Windows\System32\Drivers\etc\hosts on Windows) for Keycloak. keycloak

This is because the Docker network recognizes keycloak as a registered hostname, but it also redirects you to keycloak. Your browser is not aware of that hostname without the hosts entry.

Open your browser and navigate to [http://localhost:8761](http://localhost:8761). You’ll be redirected to Keycloak to login. Enter admin/admin for credentials and you’ll be redirected back to JHipster Registry. You’ll see all your microservice instances have been registered.

microservices architecture diagram

Navigate to [http://localhost:8080](http://localhost:8080), click sign in, and you’ll be logged in to the gateway. You can go to Entities > Blog and add a blog.

microservices architecture example

Go to Entities > Product and you can add a product too.

microservices architecture java

Pretty slick, don’t you think?! 🤓

Configure JHipster Microservices to Use Okta for Identity

One of the problems you saw in the bare-bones Spring Boot + Spring Cloud setup is you have to configure okta.oauth2.* properties in every microservice. JHipster doesn’t use the Okta Spring Boot starter. It uses oauth2-client and oauth2-resource-server Spring Boot starters instead. The configuration for OAuth 2.0 is contained in each app’s src/main/resources/config/application.yml file.

            issuer-uri: http://localhost:9080/auth/realms/jhipster
            client-id: internal
            client-secret: internal

Why Okta?

You might be wondering why you should use Okta instead of Keycloak? Keycloak works great for development and testing, and especially well if you’re on a plane with no wi-fi. However, in production, you want a system that’s always on. That’s where Okta comes in. To begin, you’ll need to create an Okta account and an application with it.

Create a Web Application in Okta

Log in to your Okta Developer account (or sign up if you don’t have an account).

  1. From the Applications page, choose Add Application.
  2. On the Create New Application page, select Web.
  3. Give your app a memorable name, add [http://localhost:8080/login/oauth2/code/okta](http://localhost:8080/login/oauth2/code/okta) as a Login redirect URI, select Refresh Token (in addition to Authorization Code), and click Done.
  4. To configure Logout to work in JHipster, Edit your app, add [http://localhost:8080](http://localhost:8080) as a Logout redirect URI, then click Save.

Configure Your OpenID Connect Settings with Spring Cloud Config

Rather than modifying each of your apps for Okta, you can use Spring Cloud Config in JHipster Registry to do it. Open docker-compose/central-server-config/application.yml and add your Okta settings.

The client ID and secret are available on your app settings page. You can find the issuer under API > Authorization Servers.

            issuer-uri: https://{yourOktaDomain}/oauth2/default
            client-id: {yourClientId}
            client-secret: {yourClientSecret}

The registry, gateway, blog, and store applications are all configured to read this configuration on startup.

Restart all your containers for this configuration to take effect.

docker-compose restart

Before you can log in, you’ll need to add redirect URIs for JHipster Registry, ensure your user is in a ROLE_ADMIN group and that groups are included in the ID token.

Log in to your Okta dashboard, edit your OIDC app, and add the following Login redirect URI:


You’ll also need to add a Logout redirect URI:


Then, click Save.

Create Groups and Add Them as Claims to the ID Token

JHipster is configured by default to work with two types of users: administrators and users. Keycloak is configured with users and groups automatically, but you need to do some one-time configuration for your Okta organization.

Create a ROLE_ADMIN group (Users > Groups > Add Group) and add your user to it. Navigate to API > Authorization Servers, and click on the the default server. Click the Claims tab and Add Claim. Name it groups, and include it in the ID Token. Set the value type to Groups and set the filter to be a Regex of .*. Click Create.

microservices architecture tutorial

Now when you hit [http://localhost:8761](http://localhost:8761) or [http://localhost:8080](http://localhost:8080), you’ll be prompted to log in with Okta!

Build a microservices architecture with Spring Boot and Spring Cloud

Build a microservices architecture with Spring Boot and Spring Cloud

It’s pretty nifty how you can configure your service registry and all your microservices in one place with Spring Cloud Config, don’t you think?! 👌

Configuring Spring Cloud Config with Git

JHipster Registry and its Spring Cloud Config server support two kinds of configuration sources: native and git. Which one is used is determined by a property. If you look in docker-compose/jhipster-registry.yml, you’ll see that native is enabled and git is commented out.

# For Keycloak to work, you need to add ' keycloak' to your hosts file

You can see the default configuration for Git at @jhipster/jhipster-registry/central-config/application.yml. You can learn more about application configuration with Spring Cloud Config in JHipster Registry’s documentation. It includes a section on encrypting configuration values.

#java #spring-boot #microservices

What is GEEK

Buddha Community

Build a microservices architecture with Spring Boot and Spring Cloud
Adaline  Kulas

Adaline Kulas


Multi-cloud Spending: 8 Tips To Lower Cost

A multi-cloud approach is nothing but leveraging two or more cloud platforms for meeting the various business requirements of an enterprise. The multi-cloud IT environment incorporates different clouds from multiple vendors and negates the dependence on a single public cloud service provider. Thus enterprises can choose specific services from multiple public clouds and reap the benefits of each.

Given its affordability and agility, most enterprises opt for a multi-cloud approach in cloud computing now. A 2018 survey on the public cloud services market points out that 81% of the respondents use services from two or more providers. Subsequently, the cloud computing services market has reported incredible growth in recent times. The worldwide public cloud services market is all set to reach $500 billion in the next four years, according to IDC.

By choosing multi-cloud solutions strategically, enterprises can optimize the benefits of cloud computing and aim for some key competitive advantages. They can avoid the lengthy and cumbersome processes involved in buying, installing and testing high-priced systems. The IaaS and PaaS solutions have become a windfall for the enterprise’s budget as it does not incur huge up-front capital expenditure.

However, cost optimization is still a challenge while facilitating a multi-cloud environment and a large number of enterprises end up overpaying with or without realizing it. The below-mentioned tips would help you ensure the money is spent wisely on cloud computing services.

  • Deactivate underused or unattached resources

Most organizations tend to get wrong with simple things which turn out to be the root cause for needless spending and resource wastage. The first step to cost optimization in your cloud strategy is to identify underutilized resources that you have been paying for.

Enterprises often continue to pay for resources that have been purchased earlier but are no longer useful. Identifying such unused and unattached resources and deactivating it on a regular basis brings you one step closer to cost optimization. If needed, you can deploy automated cloud management tools that are largely helpful in providing the analytics needed to optimize the cloud spending and cut costs on an ongoing basis.

  • Figure out idle instances

Another key cost optimization strategy is to identify the idle computing instances and consolidate them into fewer instances. An idle computing instance may require a CPU utilization level of 1-5%, but you may be billed by the service provider for 100% for the same instance.

Every enterprise will have such non-production instances that constitute unnecessary storage space and lead to overpaying. Re-evaluating your resource allocations regularly and removing unnecessary storage may help you save money significantly. Resource allocation is not only a matter of CPU and memory but also it is linked to the storage, network, and various other factors.

  • Deploy monitoring mechanisms

The key to efficient cost reduction in cloud computing technology lies in proactive monitoring. A comprehensive view of the cloud usage helps enterprises to monitor and minimize unnecessary spending. You can make use of various mechanisms for monitoring computing demand.

For instance, you can use a heatmap to understand the highs and lows in computing visually. This heat map indicates the start and stop times which in turn lead to reduced costs. You can also deploy automated tools that help organizations to schedule instances to start and stop. By following a heatmap, you can understand whether it is safe to shut down servers on holidays or weekends.

#cloud computing services #all #hybrid cloud #cloud #multi-cloud strategy #cloud spend #multi-cloud spending #multi cloud adoption #why multi cloud #multi cloud trends #multi cloud companies #multi cloud research #multi cloud market

Roberta  Ward

Roberta Ward


Consumer-Driven Contract Testing With Spring Cloud Contract


The article demonstrates how to write a contract between the producer & the consumer and how to implements the producer & the consumer side test cases for Spring Cloud Contract through an HTTP request between two microservices.


The producer is a service that exposes an API (e.g. rest endpoint) or sends a message (e.g. Kafka Producer which publishes the message to Kafka Topic)


The consumer is a service that consumes the API that is exposed by the producer or listens to a message from the producer (e.g. Kafka Consumer which consumes the message from Kafka Topic)


The contract is an agreement between the producer and consumer how the API/message will look like.

  • What endpoints can we use?
  • What input do the endpoints take?
  • What does the output look like?

Consumer-Driven Contract

Consumer-driven contract (CDD) is an approach where the consumer drives the changes in the API of the producer.

Consumer-driven contract testing is an approach to formalize above mentioned expectations into a contract between each consumer-provider pair. Once the contract is established between Provider and Consumer, this ensures that the contract will not break suddenly.

Spring Cloud Contract

Spring Cloud Contract is a project of spring-cloud that helps end-users in successfully implementing the Consumer Driven Contracts (CDC) approach. The Spring Cloud Contract Verifier is used as a tool that enables the development of Consumer Driven Contracts. Spring Cloud Contract Verifier is used with Contract Definition Language (DSL) written in Groovy or YAML.

Demo Application

To understand the concept of the Spring Cloud Contract, I have implemented two simple microservices. The code for these applications can be found on Github account.

request and response

Request and response between the consumer and the producer

Create-employee-application MS

It is the first microservice responsible for creating an employee’s profile based on the given details. We are only passing the FirstName, LastName, and Identification Number (e.g. National ID) of the employee. This microservice is calling another microservice to first check, based on the Identity Number, whether the profile has already been created for the employee.

Get-employee-application MS

This is the second microservice service that is just checking if an employee profile already exists. If the employee profile is matching with the Identification Number provided in the database, it will return the profile else return an empty profile with the EMPLOYEE_NOT_FOUND status.

The create-employee-application microservice is having a dependency on get-employee-application microservice, so we have written a contract of get-employee-application. We are not using any database here to store or retrieve employee details so that written simple logic which will help us to fetch the existing employee profile.


We are going to understand how we have done the setup for these applications. We are going to discuss the setup in each microservice one by one.

#tutorial #microservices #spring boot #spring cloud #spring boot microservices #spring cloud contract #microservices testing

Fredy  Larson

Fredy Larson


Build J2EE Microservices Architecture

I posted an article in regards to a single-page application(UI), but in this post, I’m going to introduce how to build microservice architecture for the J2EE application with Spring framework and open-source SSO framework Keycloak. This post will cover the following aspects:

  • Keycloak setup
  • Eureka service registration and discovery
  • Spring Cloud API gateway
  • Spring Security (OAuth2 login) and the integration with Keycloak
  • Microservices

The code is available in my Github and please check the docker-compose.yml at first so that you can read the rest of the post easier. One thing I need to mention here is you need to replace the IP address of the keycloak server URL with your own before running the docker containers.

version: '3.4'
      context: ./api-gateway
      - "8080:8080"
    restart: on-failure
      #overriding spring
      - eureka.client.serviceUrl.defaultZone=http://eureka-server:9091/eureka/
      - keycloak-client.server-url= ## use host name or ip of the host machine
      - eureka-server
      context: ./eureka-server
      - "9091:9091"
    restart: on-failure
      context: ./microservice-consumer
      - "9080:9080"
    restart: on-failure
      #overriding spring
      - eureka.client.serviceUrl.defaultZone=http://eureka-server:9091/eureka/
      - keycloak-client.server-url= ## use host name or ip of the host machine
      - eureka-server
      context: ./microservice-producer
      - "9081:9081"
    restart: on-failure
      #overriding spring
      - eureka.client.serviceUrl.defaultZone=http://eureka-server:9091/eureka/
      - keycloak-client.server-url= ## use host name or ip of the host machine
      - eureka-server
    image: jboss/keycloak:11.0.0
      - ./keycloak-server/realm-export.json:/tmp/keycloak/config/realm-export.json
        KEYCLOAK_USER: admin
        KEYCLOAK_PASSWORD: admin
        KEYCLOAK_IMPORT: /tmp/keycloak/config/realm-export.json
        DB_ADDR: postgres
        DB_DATABASE: keycloak
        DB_USER: keycloak
        DB_SCHEMA: public
        DB_PASSWORD: password
      - "18080:18080"
      - "-b"
      - ""
      - "-Djboss.socket.binding.port-offset=10000"
    restart: on-failure
      - postgres
      image: postgres
        - postgres_data:/var/lib/postgresql/data
        POSTGRES_DB: keycloak
        POSTGRES_USER: keycloak
        POSTGRES_PASSWORD: password
      name: keycloak_postgres_data
      driver: local

#spring boot #microservice #spring cloud #keycloak #eureka server #spring cloud gateway #spring secuirty 5 #sso authentication #java microservice #jwt token

shaik hameed


Microservices Spring Boot | Microservices Full Course | Microservices Tutorial

#spring #spring-framework #spring-boot #microservices #cloud #springcloud

Agnes  Sauer

Agnes Sauer


Feign Client — Building REST Client in Microservices

In microservice-based applications where services are usually distributed across servers or hosts, RESTful API has become second nature. With lots of these services interacting to complete a single transaction, creating REST client has become a challenge for developers. In this article, you will learn how to use FeignClient to build REST client to invoke services over HTTP in a declarative way.

FeignClient is a Spring Cloud annotation that is used to build REST client in a declarative way. Instead of conventionally writing codes calling the remote REST API, using FeignClient we only need to declare the client and define the signature of the REST API and let Spring do the building and provision the component at runtime.


Use the Spring Initializr website to generate a new Maven project with Spring Boot 2.x dependency or download the complete project from GitHub.

Import Spring Cloud Dependencies POM using Maven’s dependency management so our project could inherit all the artifacts versions in Spring Cloud.

<!-- spring-cloud -->

#spring #spring-cloud #spring-boot #microservices #cloud