Jar

Overview

Clever Cloud offers you to run any Java ARchive file. You do not need to change your code, but running it on Clever Cloud needs some configuration files or environment variable to specify the the JAR path.

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

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 organization 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 organization.
  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.

Available Java versions

Simply set the environment variable CC_JAVA_VERSION to the version you want.

ℹ️
We are using Java version 11 by default. New applications will have the CC_JAVA_VERSION environment variable set to 21.

Accepted values are 7, 8, 11, 17, 21 or graalvm-ce (for GraalVM 21.0.0.2, based on OpenJDK 11.0).

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

We are using OpenJDK distribution for mentionned 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.

Configure your Java application

You must either have the CC_JAR_PATH environment variable containing the path to your jar or provide a clevercloud/jar.json file (jar.json file in clevercloud folder which is at the root of your repository) that contains at least the following:

{
  "deploy": {
    "jarName": "path/to/jar"
  }
}

That is the least you need to do. Note that path/to/jar must not start with a / and that the path should be relative to your repository’s root.

Build options

You do not need to build and commit a JAR. Instead you can push your sources and build them with either gradle, ant or maven. Here is the configuration you need to provide in the clevercloud/jar.json file:

{
  "build": {
    "type": "maven"|"gradle"|"ant",
    "goal": "package"
  }
}

The goal field is what will be asked to the build command, like mvn package for a maven build with the package goal.

An configuration example with a maven build that generates a JAR with embedded dependencies is:

{
  "build": {
    "type": "maven",
    "goal": "package"
  },
  "deploy": {
    "jarName": "target/myproject-1.0-jar-with-dependencies.jar"
  }
}

An example of full configuration

You can pass extra arguments to the java command by using the environment variable CC_EXTRA_JAVA_ARGS and to your JAR by using CC_JAR_ARGS

The full configuration can look like the following:

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

You can use the following properties:

UsageFieldDescription
Optionalbuild → typecan be maven, gradle or ant
Optionalbuild → goalis the target you want to use to build your project
Optionaldeploy → goalthe goal/target and options you want to execute to deploy/run you project
Requiredbuild → jarNamejar file name of your application

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.

Custom run command

If you need to run a custom command (or just pass options to the program), you can specify it through the CC_RUN_COMMAND environment variable. This will override the default way of running your application.

Example:

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

Environment injection

Clever Cloud can inject environment variables that are defined in the dashboard and by add-ons linked to your application.

For Java applications, the environment is injected in the System.getProperties() object.

So, to use a variable, you just need System.getProperties().getProperty("MY_VARIABLE").

For Groovy applications, just use the System.getProperty("MY_VARIABLE").

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 Common configuration page.

You may want to have an advanced usage of your application, in which case we recommend you to read the Administrate documentation 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 us with paths to check. If these paths return something other than 200, we will consider the deployment as failed.

All you need is 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 will check all given paths. All of them must reply with a 200 OK response code.

Example

Using the path listed above, below are the expected logs:

Response from GET /my/awesome/path is 200
Response from GET /my/other/path is 500
Health check failed:
- GET /my/other/path returned 500.
If the deployment fails after this message, please update your configuration and redeploy.

In this example, the 1st path is OK, but the 2nd one failed. This give you a hint on what failed in your application.

Best practice for healthcheck endpoints

To make the most of a healthcheck endpoint, you should 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
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