Maven

Overview

Clever Cloud offers you to run your Java Maven projects. You can deploy this kind of project without changing your code, but running it on Clever Cloud needs specific environment variables or configuration files, to add parameters like your targeted container for instance.

Note : like other runtimes, Java application needs to listen on 0.0.0.0:8080

Maven is essentially a project management and comprehension tool and as such provides a way to help with managing:

• Builds
• Documentation
• Reporting
• Dependencies
• SCMs
• Releases
• Distribution

Create an application on Clever Cloud

With the web console

Refer to Quickstart for more details on application creation via the console.

With the Clever Tools CLI

1. Make sure you have clever-tools installed locally or follow our CLI getting started guide.
2. In your code folder, do clever create --type <type> <app-name> --region <zone> --org <org> where :
   1. type is the type of technology you rely on
   2. app-name the name you want for your application,
   3. zone deployment zone (par for Paris and mtl for Montreal)
   4. org the organisation ID the application will be created under.

Refer to clever create for more details on application creation with Clever Tools.

Setting up environment variables on Clever Cloud

With the Clever Cloud console

1. Go to the Clever Cloud console, and find the app you want to fine tune under it’s organisation.
2. Find the Environment variables menu and select it.
3. In this menu, you will see a form with VARIABLE_NAME and variable value fields.
4. Fill them with the desired values then select Add.
5. Don’t forget to “Update Changes” at the end of the menu.

With the Clever Tools CLI

1. Make sure you have clever-tools installed locally. Refer to our CLI getting started.
2. In your code folder, do clever env set <variable-name> <variable-value>

Refer to environment variables reference for more details on available environment variables on Clever Cloud.

You can of course create custom ones with the interface we just demonstrated, they will be available for your application.

Configure your Java application

About Cargo

To run your app, you can, for example, use plugins like cargo (Find it here). Your application must be set to listen on the port 8080.

Available Java versions

Set the environment variable CC_JAVA_VERSION to the version you want.

We follow the official Java roadmap by supporting both LTS and latest non-LTS versions.

We are using OpenJDK distribution for mentioned Java versions.

Every non-LTS versions where Premier support ends will be removed without warning as you should be able to switch to the next available non-LTS version without any trouble.

The end-of-life (EOL) versions are marked as such.

(graalvm-ce for GraalVM 21.0.0.2, based on OpenJDK 11.0)

Mandatory configuration

Option 1: JSON file in repository

The clevercloud/maven.json (maven.json file in clevercloud folder which is at the root of your repository) file must contain the goal field to indicate how to start your application:

  {
    "deploy": {
      "goal": "yourgoal"
    }
  }

An example of what can be found as a goal value is:

"-Dtest.active=false -Dexec.mainClass=\"com.example.Main\" assembly:jar-with-dependencies exec:java"

Option 2: Environment variable

If you don’t want to add a file to your repository, or if you’re using a monorepo with multiple applications in directories configured with the APP_FOLDER environment variable, you’ll probably prefer to use an environment variable for deployment configuration.

Define the goal in the CC_MAVEN_DEPLOY_GOAL environment variable, for example CC_MAVEN_DEPLOY_GOAL="spring-boot:run" for a Spring Boot application with spring-boot-maven-plugin. The former MAVEN_DEPLOY_GOAL name remains supported as an alias.

Build goal

By default, Clever Cloud builds your application with mvn package. To use another goal, set CC_MAVEN_BUILD_GOAL, for example CC_MAVEN_BUILD_GOAL="clean install -DskipTests". It takes precedence over the build.goal field of the clevercloud/maven.json file.

Optional configuration

The full configuration can look like the following:

{
  "build": {
    "type": "<string>",
    "goal": "<string>"
  },
  "deploy": {
    "goal": "<string>"
  }
}

You can use the following properties:

When build.type is maven, gradle or sbt, Clever Cloud uses the same build setup as for an automatically detected project, including your Maven settings.xml. Any other value runs a generic build.

Custom Maven settings

To use your own Maven configuration, such as credentials for a private repository or a mirror, commit a clevercloud/settings.xml file. Clever Cloud copies it to ~/.m2/settings.xml before the build. This applies to every Java build, whatever the build system, so dependencies Maven resolves on behalf of another tool use it too.

Specifying a profile

If you need to specify a maven profile (either for the build or the deploy goal, you can add it in the goal section:

"-Pmyprofile package"

Or use the CC_MAVEN_PROFILES environment variable.

Eg. CC_MAVEN_PROFILES="prod".

Monitor your application with New Relic

You can use New Relic to monitor your application on Clever Cloud.

Please refer to our New Relic documentation to configure it for your application.

Environment injection

Clever Cloud exposes environment variables defined for your application alongside those provided by linked add-ons. Read a standard variable such as MY_VARIABLE from the process environment with:

String value = System.getenv("MY_VARIABLE");

Java system properties

By default, Clever Cloud also passes variables to the generated launch command as Java system properties using -D options. When this command runs your application in the same JVM, retrieve a property with System.getProperty("MY_VARIABLE").

Variable names containing a dot (.) are not exported to the process environment. The generated launch command only receives them as Java system properties. For example, if you define my.app.config=production for your application, Clever Cloud adds -Dmy.app.config=production to the generated launch command.

A Maven or Gradle deployment goal can start the application in another JVM. In this case, forwarding system properties depends on the plugin or task configuration. When the property reaches the application JVM, retrieve its value with:

String value = System.getProperty("my.app.config"); // returns "production"

This mechanism can configure frameworks such as Spring Boot or Quarkus without modifying configuration files. Prefer standard environment variable names for portable application configuration.

Setting CC_RUN_COMMAND replaces the generated launch command, so Clever Cloud no longer adds these -D options automatically. With a custom run command, use standard environment variable names and map them in your application configuration.

Custom run command

If you need to run a custom command you can specify it through the CC_RUN_COMMAND environment variable. This will override the default maven run we use to run your application.

Example:

CC_RUN_COMMAND="java -jar somefile.jar <options>"

Git Deployment on Clever Cloud

You need Git on your computer to deploy via this tool. Here is the official website of Git to get more information: git-scm.com

Setting up your remotes

1. The “Information” page of your app gives you your Git deployment URL, it looks like this:

   1. git+ssh://git@push.clever-cloud.com/<your_app_id>.git
   2. Copy it in your clipboard

2. Locally, under your code folder, type in git init to set up a new git repository or skip this step if you already have one

3. Add the deploy URL with git remote add <name> <your-git-deployment-url>

4. Add your files via git add <files path> and commit them via git commit -m <your commit message>

5. Now push your application on Clever Cloud with git push <name> master

Refer to git deployments for more details.

Linking a database or any other add-on to your application

By linking an application to an add-on, the application has the add-on environment variables in its own environment by default.

On add-on creation

Many add-ons do exist on Clever Cloud: refer to the full list and check add-ons dedicated pages for full instructions.

During add-on creation, an Applications screen appears, with a list of your applications. You can toggle the button to Link and click next. If you finish the process of add-on creation, the application is automatically linked to it.

Add-on already exists

In the Clever Cloud console, under the Service Dependencies menu of your application, you can use the Link add-ons dropdown menu to select the name of the add-on you want to link and use the add button to finish the process.

You can also link another application from the same page in the Clever Cloud console, using the Link applications dropdown menu.

More configuration

Need more configuration? To run a script at the end of your deployment? To add your private SSH key to access private dependencies?

Go check the Configure applications page.

For advanced usage of your application, read the Develop section.

If you can’t find something or have a specific need like using a non supported version of a particular software, please reach out to the support.

Enable health check during deployment

The healthcheck allows you to limit downtimes. Indeed, you can provide Clever Cloud with paths to check. If these paths don’t return a 2xx response code, the deployment fails.

Add one (or several) environment variable as such:

CC_HEALTH_CHECK_PATH=/my/awesome/path

Or

CC_HEALTH_CHECK_PATH_0=/my/awesome/path
CC_HEALTH_CHECK_PATH_1=/my/other/path

The deployment process checks all paths. All of them must reply with a 2xx response code, such as 200 OK or 204 No Content. Clever Cloud retries with an increasing delay before it marks the deployment as failed, so an application that needs some time to start isn’t rejected on the first attempt.

When no health check path is configured, Clever Cloud requests the root path / and accepts any response code from 200 to 499: a 404 or a 401 means your application is up and answering. For Java applications, the deploy.pingPaths of the clevercloud/*.json file also count as configured paths.

Before any HTTP request, Clever Cloud checks that a service listens on the public port, 8080, on a public interface. Depending on your configuration, it’s your application, the port Docker maps from CC_DOCKER_EXPOSED_HTTP_PORT, or the first Request Flow middleware. A service on this port bound only to localhost or 127.0.0.1 makes the deployment fail with Your application is listening on localhost instead of publicly: listen on 0.0.0.0 instead.

On runtimes supporting Request Flow, when middleware runs in front of your application, Clever Cloud also checks that each middleware port and your application port are listening. With CC_REQUEST_FLOW="block", Clever Cloud only checks the service answering on the public port, not your application.

Example

With the preceding paths, here are the logs of a failing health check:

Checking public port (8080) is listening as expected
Response from GET /my/awesome/path is 200 (within expected range 200...300)
Response from GET /my/other/path is 500, expected 200...300
Error while checking /my/awesome/path, /my/other/path

In this example, the first path is OK, but the second one failed. This gives you a hint on what failed in your application.

Best practice for healthcheck endpoints

To make the most of a healthcheck endpoint, have it check your critical dependencies. For example:

• execute SELECT 1 + 1; on your database
• retrieve a specific Cellar file
• ping a specific IP through a VPN

Request Flow: Varnish, Redirection.io, OAuth2 Proxy, custom proxy

Request Flow automatically chains reverse proxies between port 8080 (public) and your application, allocating middleware ports automatically. Some services are detected from your configuration, while others must be listed explicitly in CC_REQUEST_FLOW:

• Otoroshi Challenge: set OTOROSHI_CHALLENGE_SECRET
• Varnish: add a clevercloud/varnish.vcl file or set CC_VARNISH_FILE
• Redirection.io: set CC_REDIRECTIONIO_PROJECT_KEY
• OAuth2 Proxy: set CC_REQUEST_FLOW=oauth2-proxy and its OAUTH2_PROXY_* settings

Multiple services can run simultaneously. Setting CC_REQUEST_FLOW replaces automatic detection, so list every service you need in order (e.g. oauth2-proxy,varnish). To add a custom middleware, include custom in the chain and define CC_REQUEST_FLOW_CUSTOM with @@LISTEN_PORT@@ and @@FORWARD_PORT@@ placeholders. To block public access, set CC_REQUEST_FLOW=block.

If your application manages its own HTTP server, configure it to listen on port 9000 instead of 8080 when at least one middleware is active. Clever Cloud handles this automatically for runtimes with a managed web server.

• Learn more about Request Flow
• Learn more about Varnish on Clever Cloud
• Learn more about OAuth2 Proxy on Clever Cloud
• Learn more about Redirection.io