#how to get started with quarkus

[codecraftshop]

Watch "Introduction to quarkus - quarkus tutorial | quarkus for beginners | CodeCraftShop" on YouTube

Watch “Introduction to quarkus – quarkus tutorial | quarkus for beginners | CodeCraftShop” on YouTube

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The 12 Factor App approach is for defining a clean contract between the application and running environment. The application and running environment can focus on their own domain and will not step into each others’ toes.

You might have heard of the 12 Factor App application development methodology, published by Heroku, and specifically designed to create applications that will serve as the foundation for a Software-as-a-Service offering.

In this article, we will walk you through the 12 Factor App approach.

Why the 12 Factor App?

The 12 Factor App approach for defining a clean contract between the application and running environment. The application and running environment can focus on their own domain and will not step into each others’ toes.

What is the 12 Factor App?

12 Factor App is a methodology, best practices, and manifesto that says apps should:

Use declarative formats for setup automation, to minimize time and cost for new developers joining the project;

Have a clean contract with the underlying operating system, offering maximum portability between execution environments;

Be suitable for deployment on modern cloud platforms, obviating the need for servers and systems administration;

Minimize divergence between development and production, enabling continuous deployment for maximum agility;

And can scale up without significant changes to tooling, architecture, or development practices.

The 12 Factor App has 12 factors.

How to create a 12 Factor App

For the purposes of this article I will examine how to create a 12 Factor App using Eclipse MicroProfile and Kubernetes. Eclipse MicroProfile is an open source project and community, established by the Eclipse Foundation in 2016 and includes members such as IBM, Red Hat, Tomitribe, Payara, LJC, and many others. It adopts lightweight, iterative processes and has a rapid release cycle.

It has 3 releases per year. In February 2010, MicroProfile released MicroProfile 3.3 including:

MicroProfile Config 1.4

MicroProfile Fault Tolerance 2.1

MicroProfile Health 2.2

MicroProfile JWT Authentication 1.1

MicroProfile Metrics 2.3

MicroProfile OpenAPI 1.1

MicroProfile OpenTracing 1.3

MicroProfile Rest Client 1.4

CDI 2.0

Common Annotations 1.3

JAX-RS 2.1

JSON-B 1.0

JSON-P 1.1

Eclipse MicroProfile has about a dozen implementations with various levels of support: Open Liberty, Quarkus, Payara, TomEE, Wildfly, KumuluzEE, Piranha, Apache Launcher, and others.

In this session, I will show you how to use some Eclipse MicroProfile Specs to fulfill the 12 Factor App. Let’s take a look at the 12 Factors one by one and focus on the how aspect.

1. Codebase

You can use GitHub repositories to provide a dedicated codebase per microservice so that each microservice can have its own release schedule. It is important that the codebase is version controlled.

Following the discipline of a single repository for an application forces the teams to analyze the seams of their application, and identify potential monoliths that should be split off into microservices.

2. Dependencies

Instead of packaging the third-party libraries inside your microservice, specify your dependencies in your Maven pom.xml or Gradle settings.gradle file. This enables you to freely move up to newer versions.

3. Config

Configuration is one of the most important factors. The golden rule of developing microservices is to write once, configure everywhere. When changing configuration, you don’t want to repackage your microservices. The way to achieve this is to externalise the configuration from the microservice application code. MicroProfile Config enables you to place configuration in properties files that can be easily updated without recompiling your microservices.

You can then use MicroProfile Config to access configuration “my.string.property” via

Programmatically lookup

Config config =ConfigProvider.getConfig(); config.getValue(“my.string.property”, String.class);

Via CDI Injection@Inject @ConfigProperty(name=”my.string.property”) String myPropV;

The property ”my.string.property” can be stored in System Properties, Environment Variables, or other config sources such as Kubernetes Config Map, etc. In this way, you can update the property without the need to repack the 12 Factor App.

4. Backing services

They should be configurable so that you can easily switch the attached resource by just changing the configuration. Again, MicroProfile Config and MicroProfile Rest Client can help here. MicroProfile Rest Client enables the client to treat backing services as attached resources via the following mechanism:

Specify the interface of the backing services and annotate with @RegisterRestClient

Package com.acme; @Dependent @RegisterRestClient @RegisterProvider(UnknownUrlExceptionMapper.class) @Path("/properties") public interface SystemClient { @GET @Produces(MediaType.APPLICATION_JSON) public Properties getProperties() throws UnknownUrlException, ProcessingException; }

Inject the backing service interface in the client

@Inject @RestClient private SystemClient defaultRestClient;

Bind the backing service via config property

com.acme.SystemClient/mp-rest/url=http://localhost:9080/system

In this case, if you want to swap the attaching resources simply via updating the value of the binding property as long as the services implement the same interface.

5. Build, release, run

The build stage produces an image with the source code. If you use maven, your build stage is when you issue the maven build command, e.g. mvn package.

The Release stage takes the image from the build and package with the config. If you use Docker, the command ”docker build” maps to the release stage, which then pushes the docker image to Docker hub to get ready to move towards the run stage.

The run stage is to execute the image in the execution environment. You can take “docker run” or when you deploy images to Kubernetes when issuing “kubectl apply -f deployment.yaml”.

6. Processes

Microservices should be stateless. REST is a well-adopted transport protocol, and JAX-RS, included in MicroProfile, can be used to achieve a RESTful architecture. Systems that follow the REST paradigm are stateless. In this way, underlying infrastructure can destroy or create new microservices without losing any information.

When using JAX-RS, you will need to define a subclass of Application and JAX-RS resources.

@ApplicationPath("System") public class SystemApplication extends Application {} @Path("properties") public class PropertiesResource { @GET @Produces(MediaType.APPLICATION_JSON) public JsonObject getProperties() {…} }

With the above 2 classes, the endpoint of http://host:port/System/properties will be exposed as a RESTful service.

7. Port binding

Export services using port binding. In the world of microservices, it is common that microservices talk to each other. When deploying them in the cloud, the ports need to change, so it is important to have a way to rebind the port.

MicroProfile Config can help this. You can specify the new port in Kubernetes ConfigMap, and MicroProfile Config automatically picks up the value to give the correct info to the deployed microservices. MicroProfile Rest Client can help with creating client code to connect from one microservice to another.

Refer to 4. Backing Services for the details of MicroProfile Rest Client. Once using MicroProfile, in a different environment, you can specify the backend binding service via the property of ${fully.qualified.interface.name}/mp-rest/url=http://localhost:9080/system

You can use MicroProfile config to specify the property value. If you specify the above property as an environment, you can swap any non-numeric-alpha with _ because of the restriction rules for naming environment variables. For instance, the property name com.acme.SystemClient/mp-rest/url will be com_acme_SystemClient_mp_rest_url.

8. Concurrency

The microservices should be able to be scaled up or down, depending on the workload. Knative autoscaling can help with this.

9. Disposability

Microservices should start up and shut down very fast in order to save costs and improve efficiency. The microservices should be resilient.

MicroProfile Fault Tolerance can help out with this. MicroProfile Fault Tolerance provides the following annotations to make your microservices resilient.

@Retry - recover from a brief network glitch @Timeout - specify a time out in order to prevent from waiting for a long period of time @CircuitBreaker - prevent from a repeatable errors @Bulkhead - prevent faults in one part of the system from cascading to the entire system @Fallback - provide a backup plan

The following example demonstrates the Get operation onClientSide is very resilient. It will respond to its caller within 100 ms, no matter how slow the backend service is. If there is an exception, the fallback operation will be executed.

@Path("/client") @ApplicationScoped public class ClientController { @Inject @RestClient private Service service; @Inject @ConfigProperty(name="conference") String conf; @GET @Path("/test/{parameter}") @Retry @Timeout(100) @Asynchronous @Fallback(fallbackMethod = "fallback") public CompletionStage<String> onClientSide(@PathParam("parameter") String parameter) { return CompletableFuture.completedFuture("We are live @" + conf+ "! "+ service.doSomething(parameter)); } public CompletionStage<String> fallback(@PathParam("parameter") String parameter) { return CompletableFuture.completedFuture("This is my fallback!"); } }

10. Dev/prod parity

The best practice of operating on microservices is keeping development, staging, and production environments as similar as possible in terms of code, people, and environment. Docker images are here to ensure that the environments stay the same so that you don’t run into the problem of “it runs on my laptop”.

SEE ALSO: Kubernetes: How to use readiness, liveness, and startup probes

11. Logs

Treat logs as event streams. The best practice is to system out your logs in JSON format and directly feed to ELK.

12. Admin processes

You should manage admin processes using Kubernetes Jobs so that the process will terminate automatically. You should not bake the admin processes into your microservices.

In summary, using MicroProfile and Kubernetes enables you to build a 12 Factor App. The code examples can be found from the following locations:

https://github.com/Emily-Jiang/vsummit-12factor-app-a

https://github.com/Emily-Jiang/vsummit-12factor-app-b

https://github.com/Emily-Jiang/vssummit-12factor-deployment

References

https://microprofile.io

https://openliberty.io

https://quarkus.io

https://www.12factor.net/

https://kubernetes.io/

https://github.com/Emily-Jiang/vsummit-12factor-app-a

https://github.com/Emily-Jiang/vsummit-12factor-app-b

https://github.com/Emily-Jiang/vssummit-12factor-deployment

[codecraftshop]

Watch "Introduction to quarkus - quarkus tutorial | quarkus for beginners | CodeCraftShop" on YouTube

Watch “Introduction to quarkus – quarkus tutorial | quarkus for beginners | CodeCraftShop” on YouTube

[holytheoristtastemaker]

Quarkus is a new technology aimed at cloud development. With Quarkus, you can take advantage of smaller runtimes optimized for the cloud. You don’t need to relearn new APIs. Quarkus is built on top of the best-of-breed technologies from the last decade, like Hibernate, RESTEasy, Vert.x, and MicroProfile. Quarkus is productive from day one. Quarkus is production ready. Quarkus created quite a buzz in the enterprise Java ecosystem in 2019. Like all other developers, I was curious about this new technology and saw a lot of potential in it. What exactly is Quarkus? How is it different from other technologies established in the market? How can Quarkus help me or my organization? Let’s find out. What is Quarkus? The Quarkus project dubbed itself Supersonic Subatomic Java. Is this actually real? What does this mean? To better explain the motivation behind the Quarkus project, we need to look into the current state of software development. From On-Premises to Cloud The old way to deploy applications was to use physical hardware.  With the purchase of a physical box, we  paid upfront for the hardware requirements. We had already made the investment, so it wouldn’t matter if we used all the machine resources or just a small amount. In most cases, we wouldn’t care that much as long as we could run the application. However, the Cloud is now changing the way we develop and deploy applications. In the Cloud,  we pay exactly for what we use. So we have become pickier with our hardware usage. If the application takes 10 seconds to start, we have to pay for these 10 seconds even if the application is not yet ready for others to consume. Java and the Cloud Do you remember when the first Java version was released? Allow me to refresh your memory — it was in 1996. There was no Cloud back then. In fact, it only came into existence several years later. Java was definitely not tailored for this new paradigm and had to adjust. But how could we change a paradigm after so many years tied to a physical box where costs didn’t matter as much as they do in the Cloud? It’s All About the Runtime The way that many Java libraries and frameworks evolved over the years was to perform a set of enhancements during runtime. This was a convenient way to add capabilities to your code in a safe and declarative way. Do you need dependency injection? Sure! Use annotations. Do you need a transaction? Of course! Use an annotation. In fact, you can code a lot of things by using these annotations that the runtime will pick and handle for you. But there is always a catch. The runtime requires a scan of your classpath and classes for metadata. This is an expensive operation that consumes time and memory. Quarkus Paradigm Shift Quarkus addressed this challenge by moving expensive operations like Bytecode Enhancement, Dynamic ClassLoading, Proxying, and more to compile time. The result is an environment that consumes less memory, less CPU, and faster startup. This is perfect for the use case of the Cloud, but also useful for other use cases. Everyone will benefit from less resources consumption overall, no matter the environment. Maybe Quarkus is Not So New Have you heard of or used technologies such as CDI, JAX-RS, or JPA? If so, the Quarkus stack is composed of these technologies that have been around for several years. If you know how to develop these technologies, then you will know how to develop a Quarkus application. Do you recognize the following code? @Path("books") @Consumes(APPLICATION_JSON) @Produces(APPLICATION_JSON) public class BookApi { @Inject BookRepository bookRepository; @GET @Path("/{id}") Response get(@PathParam("id")Long id) { return bookRepository.find(id) .map(Response::ok) .orElse(Response.status(NOT_FOUND)) .build(); } } Congratulations, you have your first Quarkus app! Best of Breed Frameworks and Standards The Quarkus programming model is built on top of proven standards, be it official standards or de facto standards. Right now, Quarkus has first class support for technologies like Hibernate, CDI, Eclipse MicroProfile, Kafka, Camel, Vert.x, Spring, Flyway, Kubernetes, Vault, just to name a few. When you adopt Quarkus, you will be productive from day one since you don’t really need to learn new technologies. You just use what has been out there for the past 10 years. Are you looking to use a library that isn’t yet in the Quarkus ecosystem? There is a good chance that it will work out of the box without any additional setup, unless you want to run it in GraalVM Native mode. If you want to go one step further, you could easily implement your own Quarkus extension to provide support for a particular technology and enrich the Quarkus ecosystem. Quarkus Setup So, you may be asking if there is something hiding under the covers. In fact yes there is. You are required to use a specific set of dependencies in your project that are provided by Quarkus. Don’t worry, Quarkus supports both Maven and Gradle. For convenience, you can generate a skeleton project in Quarkus starter page, and select which technologies you would like to use. Just import it in your favorite IDE and you are ready to go. Here is a sample Maven project to use JAX-RS with RESTEasy and JPA with Hibernate: 4.0.0 org.acme code-with-quarkus 1.0.0-SNAPSHOT 3.8.1 true 1.8 1.8 UTF-8 UTF-8 1.3.0.Final quarkus-universe-bom io.quarkus 1.3.0.Final 2.22.1 ${quarkus.platform.group-id} ${quarkus.platform.artifact-id} ${quarkus.platform.version} pom import io.quarkus quarkus-resteasy io.quarkus quarkus-junit5 test io.rest-assured rest-assured test io.quarkus quarkus-hibernate-orm io.quarkus quarkus-resteasy-jsonb io.quarkus quarkus-maven-plugin ${quarkus-plugin.version} build maven-compiler-plugin ${compiler-plugin.version} maven-surefire-plugin ${surefire-plugin.version} org.jboss.logmanager.LogManager You might have noticed that most of the dependencies start with the groupId io.quarkus and that they are not the usual dependencies that you might find for Hibernate, Resteasy, or Junit. Quarkus Dependencies Now, you may be wondering why Quarkus supplies their own wrapper versions around these popular libraries. The reason is to provide a bridge between the library and Quarkus to resolve the runtime dependencies at compile time. This is where the magic of Quarkus happens and provides projects with fast start times and smaller memory footprints. Does this mean that you are constrained to use only Quarkus specific libraries? Absolutely not. You can use any library you wish. You run Quarkus applications on the JVM as usual, where you don’t have limitations. GraalVM and Native Images Perhaps you already heard about this project called GraalVM by Oracle Labs? In essence, GraalVM is a Universal Virtual Machine to run applications in multiple languages. One of the most interesting features is the ability to build your application in a Native Image and run it even faster! In practice, this means that you just have an executable to run with all the required dependencies of your application resolved at compile time. This does not run on the JVM — it is a plain executable binary file, but includes all necessary components like memory management and thread scheduling from a different virtual machine, called Substrate VM to run your application. For convenience, the sample Maven project already has the required setup to build your project as native. You do need to have GraalVM in your system with the native-image tool installed. Follow these instructions on how to do so. After that, just build as any other Maven project but with the native profile: mvn verify -Pnative. This will generate a binary runner in the target folder, that you can run as any other binary, with ./project-name-runner. The following is a sample output of the runner in my box: [io.quarkus] (main) code-with-quarkus 1.0.0-SNAPSHOT (powered by Quarkus 1.3.0.Final) started in 0.023s. Listening on: http://0.0.0.0:8080 INFO [io.quarkus] (main) Profile prod activated. [io.quarkus] (main) Installed features: [agroal, cdi, hibernate-orm, narayana-jta, resteasy, resteasy-jsonb] Did you notice the startup time? Only 0.023s. Yes, our application doesn’t have much, but still pretty impressive. Even for real applications, you will see startup times in the order of milliseconds. You can learn more about GraalVM on their website. Developer Productivity We have seen that Quarkus could help your company become Cloud Native. Awesome. But what about the developer? We all like new shiny things, and we are also super lazy. What does Quarkus do for the developer that cannot be done with other technologies? Well, how about hot reloading that actually works without using external tools or complicated tricks? Yes, it is true. After 25 years, since Java was born, we now have a reliable way to change our code and see those changes with a simple refresh. Again, this is accomplished by the way Quarkus works internally. Everything is just code, so you don’t have to worry about the things that made hot reloading difficult anymore. It is a trivial operation. To accomplish this, you have to run Quarkus in Development Mode. Just run mvn quarkus:dev and you are good to go. Quarkus will start up and you are free to do the changes to your code and immediately see them. For instance, you can change your REST endpoint parameters, add new methods, and change paths. Once you invoke them, they will be updated reflecting your code changes. How cool is that? Is Quarkus Production Ready? All of this seems to be too good to be true, but is Quakus actually ready for production environments? Yes it is. A lot of companies are already adopting Quarkus as their development/runtime environment. Quarkus has a very fast release cadence (every few weeks), and a strong Open Source community that helps every developer in the Java community, whether they are just  getting started with Quarkus or are an advanced user. Check out this sample application that you can download or clone. You can also read some of the adoption stories in a few blog posts so you can have a better idea of user experiences when using Quarkus. Conclusion After a year of its official announcement, Quarkus is already on version 1.3.1.Final. A lot of effort is being put in the project to help companies and developers to write applications that they can run natively in the Cloud. We don’t know how far Quarkus can go, but one thing is for certain: Quarkus shook the entire Java ecosystem in a space dominated by Spring. I think the Java ecosystem can only win by having multiple offerings that can push each other and innovate to keep themselves competitives.

http://damianfallon.blogspot.com/2020/04/getting-started-with-quarkus.html