Peak Flow

This project can be used as a starting point to create your own Vaadin application with Spring Boot. It contains all the necessary configuration and some placeholder files to get you started.

Running the application

The project is a standard Maven project. To run it from the command line, type mvnw (Windows), or ./mvnw (Mac & Linux), then open http://localhost:8080 in your browser.

You can also import the project to your IDE of choice as you would with any Maven project. Read more on how to import Vaadin projects to different IDEs (Eclipse, IntelliJ IDEA, NetBeans, and VS Code).

Deploying to Production

To create a production build, call mvnw clean package -Pproduction (Windows), or ./mvnw clean package -Pproduction (Mac & Linux). This will build a JAR file with all the dependencies and front-end resources, ready to be deployed. The file can be found in the target folder after the build completes.

Once the JAR file is built, you can run it using java -jar target/peakflow-1.0-SNAPSHOT.jar

Project structure

• MainLayout.java in src/main/java contains the navigation setup (i.e., the side/top bar and the main menu). This setup uses App Layout.
• views package in src/main/java contains the server-side Java views of your application.
• views folder in src/main/frontend contains the client-side JavaScript views of your application.
• themes folder in src/main/frontend contains the custom CSS styles.

Useful links

• Read the documentation at vaadin.com/docs.
• Follow the tutorial at vaadin.com/docs/latest/tutorial/overview.
• Create new projects at start.vaadin.com.
• Search UI components and their usage examples at vaadin.com/docs/latest/components.
• View use case applications that demonstrate Vaadin capabilities at vaadin.com/examples-and-demos.
• Build any UI without custom CSS by discovering Vaadin's set of CSS utility classes.
• Find a collection of solutions to common use cases at cookbook.vaadin.com.
• Find add-ons at vaadin.com/directory.
• Ask questions on Stack Overflow or join our Forum.
• Report issues, create pull requests in GitHub.

Deploying using Docker

To build the Dockerized version of the project, run

mvn clean package -Pproduction
docker build . -t peakflow:latest

Once the Docker image is correctly built, you can test it locally using

docker run -p 8080:8080 peakflow:latest

Deploying using Kubernetes

We assume here that you have the Kubernetes cluster from Docker Desktop running (can be enabled in the settings).

First build the Docker image for your application. You then need to make the Docker image available to you cluster. With Docker Desktop Kubernetes, this happens automatically. With Minikube, you can run eval $(minikube docker-env) and then build the image to make it available. For other clusters, you need to publish to a Docker repository or check the documentation for the cluster.

The included kubernetes.yaml sets up a deployment with 2 pods (server instances) and a load balancer service. You can deploy the application on a Kubernetes cluster using

kubectl apply -f kubernetes.yaml

If everything works, you can access your application by opening http://localhost:8000/. If you have something else running on port 8000, you need to change the load balancer port in kubernetes.yaml.

Tip: If you want to understand which pod your requests go to, you can add the value of VaadinServletRequest.getCurrent().getLocalAddr() somewhere in your UI.

Troubleshooting

If something is not working, you can try one of the following commands to see what is deployed and their status.

kubectl get pods
kubectl get services
kubectl get deployments

If the pods say Container image "peakflow:latest" is not present with pull policy of Never then you have not built your application using Docker or there is a mismatch in the name. Use docker images ls to see which images are available.

If you need even more information, you can run

kubectl cluster-info dump

that will probably give you too much information but might reveal the cause of a problem.

If you want to remove your whole deployment and start over, run

kubectl delete -f kubernetes.yaml