The todo-backend quickstart demonstrates how to implement a backend that exposes a HTTP API with Jakarta REST
to manage a list of ToDo which are persisted in a database with JPA.
This quickstart shows how to setup a local deployment of this backend as well as a deployment on OpenShift to connect to a PostgreSQL database also hosted on OpenShift.
The todo-backend quickstart demonstrates how to implement a backend that exposes a HTTP API with Jakarta REST
to manage a list of ToDo which are persisted in a database with JPA.
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The backend exposes a HTTP API to manage a list of todos that complies with the specs defined at todobackend.com.
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It requires a connection to a PostgreSQL database to persist the todos.
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It uses the Server Provisioning for local and cloud deployment
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It can be build with WildFly S2I images for cloud deployment
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It is deployed on OpenShift using the Helm Chart for WildFly.
The application this project produces is designed to be run on WildFly Application Server 35 or later.
All you need to build this project is Java SE 17.0 or later, and Maven 3.6.0 or later. See Configure Maven to Build and Deploy the Quickstarts to make sure you are configured correctly for testing the quickstarts.
This backend is built using WildFly S2I Builder and Runtime images.
When the image is built, org.wildfly.plugins:wildfly-maven-plugin plugin provisions the WildFly application server and all the feature packs it needs for its features.
The layers are defined in the pom.xml file in the <configuration> section of the org.wildfly.plugins:wildfly-maven-plugin plugin:
<layers>
<layer>cloud-server</layer>
<layer>postgresql-datasource</layer>
</layers>The cloud-server layer provides everything needed to run the backend on OpenShift. This also includes access to
Jakarta EE APIs such as CDI, Jakarta REST, JPA, etc. These two layers comes from the WildFly feature pack provided in the
WildFly S2I builder image.
The postgresql-datasource layer provides a JDBC driver and DataSource to connect to a PostgreSQL database. It is also provided by
org.wildfly:wildfly-datasources-galleon-pack which is included in the WildFly S2I image.
The Git repository for this feature pack is hosted at https://github.com/wildfly-extras/wildfly-datasources-galleon-pack.
It provides JDBC drivers and datasources for different databases but for this quickstart, we will only need the postgresql-datasource.
As mentioned, the JDBC drivers and datasource configuration that the backend uses to connect to the PostgreSQL database
is provided by the org.wildfly:wildfly-datasources-galleon-pack feature pack.
By default, it exposes a single datasource.
In the backend, the name of this datasource is ToDos and is specified in the persistence.xml to configure JPA:
<persistence-unit name="primary">
<jta-data-source>java:jboss/datasources/ToDos</jta-data-source>
</persistence-unit>At runtime, we only need a few environment variables to establish the connection from WildFly to the external PostgreSQL database:
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POSTGRESQL_DATABASE- the name of the database (that will be calledtodos) -
POSTGRESQL_SERVICE_HOST- the host to connect to the database -
POSTGRESQL_SERVICE_PORT- The port to connect to the database -
POSTGRESQL_USER&POSTGRESQL_PASSWORD- the credentials to connect to the database -
POSTGRESQL_DATASOURCE- The name of the datasources (as mentioned above, it will beToDos)
The Web frontend for this quickstart uses JavaScript calls to query the backend’s HTTP API.
We must enable Cross-Origin Resource Sharing (CORS) filters in the undertow subsystem of WildFly to allow
these HTTP requests to succeed.
This script is executed at build time and will provide the following HTTP headers to enabled CORS:
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Access-Control-Allow-Origin: * -
Access-Control-Allow-Methods: GET, POST, OPTION, PUT, DELETE, PATCH -
Access-Control-Allow-Headers: accept, authorization, content-type, x-requested-with -
Access-Control-Allow-Credentials: true -
Access-Control-Max-Age: 1
By default, the backend accepts requests from any origin (*). This is only simplicity. It is possible to restrict
the allowed origin using the environment variable CORS_ORIGIN at runtime.
The backend is packaged and deployed on a provisioned server:
$ mvn clean package -Pprovisioned-serverBefore running the backend locally, we need to have a local PostgreSQL database that we can connect to.
We use the postgresql docker image to create one:
$ docker run --name todo-backend-db -e POSTGRES_USER=todos -e POSTGRES_PASSWORD=mysecretpassword -p 5432:5432 postgresThis will create a database named todos that we can connect to on localhost:5432 with the credentials todos / mysecretpassword.
With the PostgreSQL database running, we can start the backend by passing the required environment variables to connect to the database:
$ ./target/server/bin/standalone.sh -Denv.POSTGRESQL_DATABASE=todos -Denv.POSTGRESQL_DATASOURCE=ToDos -Denv.POSTGRESQL_SERVICE_HOST=localhost -Denv.POSTGRESQL_SERVICE_PORT=5432 -Denv.POSTGRESQL_USER=todos -Denv.POSTGRESQL_PASSWORD=mysecretpasswordThe backend is running, and we can use the HTTP API to manage a list of todos:
# get a list of todos
$ curl http://localhost:8080/todo-backend
[]
# create a todo with the title "This is my first todo item!"
$ curl -X POST -H "Content-Type: application/json" -d '{"title": "This is my first todo item!"}' http://localhost:8080/todo-backend
{"completed":false,"id":1,"order":0,"title":"This is my first todo item!","url":"https://localhost:8080/1"}%
# get a list of todos with the one that was just created
$ curl http://localhost:8080/todo-backend
[{"completed":false,"id":1,"order":0,"title":"This is my first todo item!","url":"https://localhost:8080/1"}]Please note that the quickstart includes integration tests, which may be executed using the following command:
$ mvn verify -Pintegration-testingOn OpenShift, the S2I build with Apache Maven uses an openshift Maven profile to provision a WildFly server, deploy and run the quickstart in OpenShift environment.
The server provisioning functionality is provided by the WildFly Maven Plugin, and you may find its configuration in the quickstart pom.xml:
<profile>
<id>openshift</id>
<build>
<plugins>
<plugin>
<groupId>org.wildfly.plugins</groupId>
<artifactId>wildfly-maven-plugin</artifactId>
<configuration>
<discover-provisioning-info>
<version>${version.server}</version>
<context>cloud</context>
</discover-provisioning-info>
<add-ons>...</add-ons>
</configuration>
<executions>
<execution>
<goals>
<goal>package</goal>
</goals>
</execution>
</executions>
</plugin>
...
</plugins>
</build>
</profile>You may note that unlike the provisioned-server profile it uses the cloud context which enables a configuration tuned for OpenShift environment.
The plugin uses WildFly Glow to discover the feature packs and layers required to run the application, and provisions a server containing those layers.
If you get an error or the server is missing some functionality which cannot be auto-discovered, you can download the WildFly Glow CLI and run the following command to see more information about what add-ons are available:
wildfly-glow show-add-onsThis section contains the basic instructions to build and deploy this quickstart to WildFly for OpenShift or WildFly for OpenShift Online using Helm Charts.
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You must be logged in OpenShift and have an
occlient to connect to OpenShift -
Helm must be installed to deploy the backend on OpenShift.
Once you have installed Helm, you need to add the repository that provides Helm Charts for WildFly.
$ helm repo add wildfly https://docs.wildfly.org/wildfly-charts/
"wildfly" has been added to your repositories
$ helm search repo wildfly
NAME CHART VERSION APP VERSION DESCRIPTION
wildfly/wildfly ... ... Build and Deploy WildFly applications on OpenShift
wildfly/wildfly-common ... ... A library chart for WildFly-based applicationsAdd the bitnami repository which provides an helm chart for PostgreSQL:
$ helm repo add bitnami https://charts.bitnami.com/bitnami
"bitnami" has been added to your repositoriesThe Helm Chart for this quickstart contains all the information to build an image from the source code using S2I and install it with the database:
dependencies:
- name: postgresql
repository: https://charts.bitnami.com/bitnami
version: ...
- name: wildfly
repository: http://docs.wildfly.org/wildfly-charts/
version: ...So we need to update the dependecies of our Helm Chart.
$ helm dependency update charts/Log in to your OpenShift instance using the oc login command.
The backend will be built and deployed on OpenShift with a Helm Chart for WildFly.
Navigate to the root directory of this quickstart and run the following command:
$ helm install todo-backend charts --wait --timeout=10m0s
NAME: todo-backend
...
STATUS: deployed
REVISION: 1This command will return once the application has successfully deployed. In case of a timeout, you can check the status of the application with the following command in another terminal:
oc get deployment todo-backendThe Helm Chart for this quickstart contains all the information to build an image from the source code using S2I on Java 17:
apiVersion: v2
name: todo-backend-chart
description: A Helm chart to deploy a WildFly todo-backend application and its Postgresql database
type: application
version: 1.0.0
appVersion: 31.0.0.Final
dependencies:
- name: postgresql
repository: https://charts.bitnami.com/bitnami
version: 13.1.5
- name: wildfly
repository: http://docs.wildfly.org/wildfly-charts/
version: 2.3.2This will create a new deployment on OpenShift and deploy the application.
If you want to see all the configuration elements to customize your deployment you can use the following command:
$ helm show readme wildfly/wildflyGet the URL of the route to the deployment.
$ oc get route todo-backend -o jsonpath="{.spec.host}"Access the application in your web browser using the displayed URL.
The integration tests included with this quickstart, which verify that the quickstart runs correctly, may also be run with the quickstart running on OpenShift.
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Note
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The integration tests expect a deployed application, so make sure you have deployed the quickstart on OpenShift before you begin. |
Run the integration tests using the following command to run the verify goal with the integration-testing profile activated and the proper URL:
$ mvn verify -Pintegration-testing -Dserver.host=https://$(oc get route todo-backend --template='{{ .spec.host }}') |
Note
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The tests are using SSL to connect to the quickstart running on OpenShift. So you need the certificates to be trusted by the machine the tests are run from. |
$ helm uninstall todo-backendThe Helm Chart also contains the environment variables required to connect to the PostgreSQL database.
In local deployment the credentials were passed directly as the values of the environment variables.
For OpenShift, we rely on secrets so that the credentials are never copied outside OpenShift:
deploy:
env:
- name: POSTGRESQL_PASSWORD
valueFrom:
secretKeyRef:
key: database-password
name: todo-backend-dbWhen the application is deployed, the value for the POSTGRESQL_PASSWORD will be taken from the key database-password
in the secret todo-backend-db.
Once the backend is deployed on OpenShift, it can be accessed from the route todo-backend.
Let’s find the host that we can use to connect to this backend:
$ oc get route todo-backend -o jsonpath="{.spec.host}"
todo-backend-jmesnil1-dev.apps.sandbox.x8i5.p1.openshiftapps.comThis value will be different for every installation of the backend.
To be able to connect to the backend from the ToDo Backend Specs or Client, then prepend the host with https://, and append the relative web context /todo-backend. For the previous example host this would be https://todo-backend-jmesnil1-dev.apps.sandbox.x8i5.p1.openshiftapps.com/todo-backend.
We can verify that this application is properly working as a ToDo Backend by running its specs on it.
Once all tests passed, we can use the todobackend client to have a Web application connected to the backend.
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Note
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todobackend.com is an external service used to showcase this quickstart. It might not always be functional but does not impact the availability of this backend. |
For Kubernetes, the build with Apache Maven uses an openshift Maven profile to provision a WildFly server, suitable for running on Kubernetes.
The server provisioning functionality is provided by the WildFly Maven Plugin, and you may find its configuration in the quickstart pom.xml:
<profile>
<id>openshift</id>
<build>
<plugins>
<plugin>
<groupId>org.wildfly.plugins</groupId>
<artifactId>wildfly-maven-plugin</artifactId>
<configuration>
<discover-provisioning-info>
<version>${version.server}</version>
<context>cloud</context>
</discover-provisioning-info>
<add-ons>...</add-ons>
</configuration>
<executions>
<execution>
<goals>
<goal>package</goal>
</goals>
</execution>
</executions>
</plugin>
...
</plugins>
</build>
</profile>You may note that unlike the provisioned-server profile it uses the cloud context which enables a configuration tuned for Kubernetes environment.
The plugin uses WildFly Glow to discover the feature packs and layers required to run the application, and provisions a server containing those layers.
If you get an error or the server is missing some functionality which cannot be auto-discovered, you can download the WildFly Glow CLI and run the following command to see more information about what add-ons are available:
wildfly-glow show-add-onsThis section contains the basic instructions to build and deploy this quickstart to Kubernetes using Helm Charts.
In this example we are using Minikube as our Kubernetes provider. See the Minikube Getting Started guide for how to install it. After installing it, we start it with 4GB of memory.
minikube start --memory='4gb'The above command should work if you have Docker installed on your machine. If, you are using Podman instead of Docker, you will also need to pass in --driver=podman, as covered in the Minikube documentation.
Once Minikube has started, we need to enable its registry since that is where we will push the image needed to deploy the quickstart, and where we will tell the Helm charts to download it from.
minikube addons enable registryIn order to be able to push images to the registry we need to make it accessible from outside Kubernetes. How we do this depends on your operating system. All the below examples will expose it at localhost:5000
# On Mac:
docker run --rm -it --network=host alpine ash -c "apk add socat && socat TCP-LISTEN:5000,reuseaddr,fork TCP:$(minikube ip):5000"
# On Linux:
kubectl port-forward --namespace kube-system service/registry 5000:80 &
# On Windows:
kubectl port-forward --namespace kube-system service/registry 5000:80
docker run --rm -it --network=host alpine ash -c "apk add socat && socat TCP-LISTEN:5000,reuseaddr,fork TCP:host.docker.internal:5000"-
Helm must be installed to deploy the backend on Kubernetes.
Once you have installed Helm, you need to add the repository that provides Helm Charts for WildFly.
$ helm repo add wildfly https://docs.wildfly.org/wildfly-charts/
"wildfly" has been added to your repositories
$ helm search repo wildfly
NAME CHART VERSION APP VERSION DESCRIPTION
wildfly/wildfly ... ... Build and Deploy WildFly applications on OpenShift
wildfly/wildfly-common ... ... A library chart for WildFly-based applicationsAdd the bitnami repository which provides an helm chart for PostgreSQL:
$ helm repo add bitnami https://charts.bitnami.com/bitnami
"bitnami" has been added to your repositoriesThe Helm Chart for this quickstart contains all the information to build an image from the source code using S2I and install it with the database:
dependencies:
- name: postgresql
repository: https://charts.bitnami.com/bitnami
version: ...
- name: wildfly
repository: http://docs.wildfly.org/wildfly-charts/
version: ...So we need to update the dependecies of our Helm Chart.
$ helm dependency update charts/The backend will be built and deployed on Kubernetes with a Helm Chart for WildFly.
Navigate to the root directory of this quickstart and run the following commands:
mvn -Popenshift package wildfly:imageThis will use the openshift Maven profile we saw earlier to build the application, and create a Docker image containing the WildFly server with the application deployed. The name of the image will be todo-backend.
Next we need to tag the image and make it available to Kubernetes. You can push it to a registry like quay.io. In this case we tag as localhost:5000/todo-backend:latest and push it to the internal registry in our Kubernetes instance:
# Tag the image
docker tag todo-backend localhost:5000/todo-backend:latest
# Push the image to the registry
docker push localhost:5000/todo-backend:latestIn the below call to helm install which deploys our application to Kubernetes, we are passing in some extra arguments to tweak the Helm build:
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--set wildfly.build.enabled=false- This turns off the s2i build for the Helm chart since Kubernetes, unlike OpenShift, does not have s2i. Instead, we are providing the image to use. -
--set wildfly.deploy.route.enabled=false- This disables route creation normally performed by the Helm chart. On Kubernetes we will use port-forwards instead to access our application, since routes are an OpenShift specific concept and thus not available on Kubernetes. -
--set wildfly.image.name="localhost:5000/todo-backend"- This tells the Helm chart to use the image we built, tagged and pushed to Kubernetes' internal registry above.
$ helm install todo-backend charts --wait --timeout=10m0s --set wildfly.build.enabled=false --set wildfly.deploy.route.enabled=false --set wildfly.image.name="localhost:5000/todo-backend"
NAME: todo-backend
...
STATUS: deployed
REVISION: 1This command will return once the application has successfully deployed. In case of a timeout, you can check the status of the application with the following command in another terminal:
kubectl get deployment todo-backendThe Helm Chart for this quickstart contains all the information to build an image from the source code using S2I on Java 17:
apiVersion: v2
name: todo-backend-chart
description: A Helm chart to deploy a WildFly todo-backend application and its Postgresql database
type: application
version: 1.0.0
appVersion: 31.0.0.Final
dependencies:
- name: postgresql
repository: https://charts.bitnami.com/bitnami
version: 13.1.5
- name: wildfly
repository: http://docs.wildfly.org/wildfly-charts/
version: 2.3.2This will create a new deployment on Kubernetes and deploy the application.
If you want to see all the configuration elements to customize your deployment you can use the following command:
$ helm show readme wildfly/wildflyTo be able to connect to our application running in Kubernetes from outside, we need to set up a port-forward to the todo-backend service created for us by the Helm chart.
This service will run on port 8080, and we set up the port forward to also run on port 8080:
kubectl port-forward service/todo-backend 8080:8080The server can now be accessed via http://localhost:8080 from outside Kubernetes. Note that the command to create the port-forward will not return, so it is easiest to run this in a separate terminal.
The integration tests included with this quickstart, which verify that the quickstart runs correctly, may also be run with the quickstart running on Kubernetes.
|
Note
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The integration tests expect a deployed application, so make sure you have deployed the quickstart on Kubernetes before you begin. |
Run the integration tests using the following command to run the verify goal with the integration-testing profile activated and the proper URL:
$ mvn verify -Pintegration-testing -Dserver.host=http://localhost:8080 $ helm uninstall todo-backendTo stop the port forward you created earlier use:
$ kubectl port-forward service/todo-backend 8080:8080The Helm Chart also contains the environment variables required to connect to the PostgreSQL database.
In local deployment the credentials were passed directly as the values of the environment variables.
For Kubernetes, we rely on secrets so that the credentials are never copied outside Kubernetes:
deploy:
env:
- name: POSTGRESQL_PASSWORD
valueFrom:
secretKeyRef:
key: database-password
name: todo-backend-dbWhen the application is deployed, the value for the POSTGRESQL_PASSWORD will be taken from the key database-password
in the secret todo-backend-db.
This quickstart shows how the datasource feature pack provided by WildFly simplifies the deployment of a WildFly Jakarta EE backend on OpenShift to connect to an external database and exposes an HTTP API.
The use of a Server Provisioned deployment makes it seamless to move from a local deployment for development to a deployment on cloud platforms such as OpenShift and Kubernetes.