Getting Started Deploying Ratpack Apps

Page last updated: August 20, 2015

This guide is intended to walk you through deploying a Ratpack app to Cloud Foundry. If you experience a problem following the steps below, check the Troubleshooting Cloud Foundry topic or refer to the Troubleshooting Application Deployment and Health topic.

Sample App Step
If you want to go through this tutorial using the sample app, run git clone https://github.com/cloudfoundry-samples/pong_matcher_groovy.git to clone the pong_matcher_groovy app from GitHub, and follow the instructions in the Sample App Step sections.

Note: Ensure that your Ratpack app runs locally before continuing with this procedure.

Deploy a Ratpack Application

This section describes how to deploy a Ratpack application to Cloud Foundry.

Prerequisites

  • A Ratpack app that runs locally on your workstation
  • Intermediate to advanced Ratpack knowledge
  • The cf Command Line Interface (CLI)
  • JDK 1.7 or 1.8 for Java 7 or 8 configured on your workstation

Note: You can develop Ratpack applications in Java 7 or 8 or any JVM language. The Cloud Foundry Java buildpack uses JDK 1.8, but you can modify the buildpack and the manifest for your app to compile to JDK 1.7. Refer to Step 8: Configure the Deployment Manifest.

Step 1: Declare App Dependencies

Declare all the dependency tasks for your app in the build script of your chosen build tool. The table lists build script information for Gradle and Maven and provides documentation links for each build tool.

Build Tool Build Script Documentation
Gradlebuild.gradleGradle User Guide
Mavenpom.xmlApache Maven Project Documentation

Sample App Step
You can skip this step. The build.gradle file contains the dependencies for the pong_matcher_groovy sample app, as the example below shows. 

dependencies {
  // SpringLoaded enables runtime hot reloading.
  // It is not part of the app runtime and is not shipped in the distribution.
  springloaded "org.springframework:springloaded:1.2.0.RELEASE"

  // Default SLF4J binding.  Note that this is a blocking implementation.
  // See here for a non blocking appender http://logging.apache.org/log4j/2.x/manual/async.html
  runtime 'org.slf4j:slf4j-simple:1.7.7'

  compile group: 'redis.clients', name: 'jedis', version: '2.5.2', transitive: true

  testCompile "org.spockframework:spock-core:0.7-groovy-2.0"
}

Step 2: Allocate Sufficient Memory

Use the cf push -m command to specify the amount of memory that should be allocated to the application. Memory allocated this way is done in preset amounts of 64M, 128M, 256M, 512M, 1G, or 2G. For example:

$ cf push -m 128M

When your app is running, you can use the cf app APP_NAME command to see memory utilization.

Sample App Step
You can skip this step. In the manifest.yml of the pong_matcher_groovy sample app, the memory sub-block of the applications block allocates 512 MB to the app.

Step 3: Provide a JDBC Driver

The Java buildpack does not bundle a JDBC driver with your application. If your application accesses a SQL RDBMS, you must do the following:

  • Include the appropriate driver in your application.
  • Create a dependency task for the driver in the build script for your build tool or IDE.

Sample App Step
You can skip this step. The pong_matcher_groovy sample app does not require a JDBC driver.

Step 4: (Optional) Configure a Procfile

A Procfile enables you to declare required runtime processes, called process types, for your web app. Process managers in a server use the process types to run and manage the workload.

When you deploy, Cloud Foundry determines if a Procfile exists and uses the Procfile to configure your app with the specified settings.

In a Procfile, you declare one process type per line and use the following syntax, as shown in the example below:

  • PROCESS_TYPE is the command name in the format of an alphanumeric string.
  • COMMAND is the command line to launch the process.

Example process type syntax: 

PROCESS_TYPE: COMMAND

You create a Procfile and add a command line for a web process type. Store the Procfile in the root directory of your app. The example shows a process type that starts the launch script created by the build process.

Example Procfile: 

web: build/install/MY-PROJECT-NAME/bin/MY-PROJECT-NAME

Sample App Step
You can skip this step. The pong_matcher_groovy app does not require a Procfile.

Step 5: Create and Bind a Service Instance for a Ratpack Application

This section describes using the CLI to configure a Redis managed service instance for an app.

Cloud Foundry supports two types of service instances:

  • Managed services integrate with Cloud Foundry through service brokers that offer services and plans and manage the service calls between Cloud Foundry and a service provider.
  • User-provided service instances enable you to connect your application to pre-provisioned external service instances.

For more information about creating and using service instances, refer to the Services Overview topic.

Create a Service Instance

Run cf marketplace to view managed and user-provided services and plans available to you.

The example shows two of the available managed database-as-a-service providers and their offered plans: elephantsql PostgreSQL as a Service and rediscloud Enterprise-Class Redis for Developers.

$ cf marketplace
Getting services from marketplace in org Cloud-Apps / space development as [email protected]...
OK

service       plans        description
...

elephantsql   turtle, panda, elephant      PostgreSQL as a Service
...
rediscloud    25mb, 100mb, 1gb, 10gb, 50gb Enterprise-Class Redis for Developers
...

Run cf create-service SERVICE PLAN SERVICE_INSTANCE to create a service instance for your app. Choose a SERVICE and PLAN from the list, and provide a unique name for the SERVICE_INSTANCE.

Sample App Step
Run cf create-service rediscloud 25mb baby-redis. This creates a service instance named baby-redis that uses the rediscloud service and the 25mb plan, as the example below shows. 

$ cf create-service rediscloud 25mb baby-redis
Creating service baby-redis in org Cloud-Apps / space development as [email protected]....
OK

Bind a Service Instance

When you bind an app to a service instance, Cloud Foundry writes information about the service instance to the VCAP_SERVICES app environment variable. The app can use this information to integrate with the service instance.

Most services support bindable service instances. Refer to your service provider’s documentation to confirm if they support this functionality.

You can bind a service to an application with the command cf bind-service APPLICATION SERVICE_INSTANCE.

Alternately, you can configure the deployment manifest file by adding a services sub-block to the applications block and specifying the service instance. For more information and an example on service binding using a manifest, see the Sample App step.

Sample App Step
You can skip this step because the service instance is already bound. Open the manifest.yml file in a text editor to view the bound service instance information. Locate the file in the app root directory and search for the services sub-block in the applications block, as the example below shows. 

---
applications:
...
  services:
    - baby-redis

Step 6: Configure the Deployment Manifest

You can specify deployment options in the manifest.yml that the cf push command uses when deploying your app.

Refer to the Deploying with Application Manifests topic for more information.

Sample App Step
You can skip this step. The manifest.yml file for the pong_matcher_groovy sample app does not require any additional configuration to deploy the app.

Step 7: Log in and Target the API Endpoint

Run cf login -a API_ENDPOINT, enter your login credentials, and select a space and org. The API endpoint is the URL of the Cloud Controller in your Cloud Foundry instance.

Sample App Step
You must do this step to run the sample app.

Step 8: Deploy the Application

Note: You must use the cf CLI to deploy apps.

From the root directory of your application, run cf push APP-NAME -p PATH-TO-FILE.distZip to deploy your application.

Note: You must deploy the .distZip artifact for a Ratpack app, and you must include the path to the .distZip file in the cf push command using the -p option if you do not declare the path in the applications block of the manifest file. For more information, refer to the Tips for Java Developers topic.

cf push APP-NAME creates a URL route to your application in the form HOST.DOMAIN, where HOST is your APP-NAME and DOMAIN is specified by your administrator. Your DOMAIN isshared-domain.com. For example: cf push my-app creates the URL my-app.shared-domain.com.

The URL for your app must be unique from other apps that Cloud Foundry hosts or the push will fail. Use the following options to help create a unique URL:

  • -n to assign a different HOST name for the app
  • --random-route to create a URL that includes the app name and random words
  • cf help push to view other options for this command

If you want to view log activity while the app deploys, launch a new terminal window and run cf logs APP-NAME.

Once your app deploys, browse to your app URL. Search for the urls field in the App started block in the output of the cf push command. Use the URL to access your app online.

Sample App Step
1. Change to the appdirectory, and run ./gradlew distZip to build the app.
2. Run cf push pong_matcher_groovy -n HOST_NAME to push the app.

Example: cf push pong_matcher_groovy -n groovy-ratpack-app

Note: You do not have to include the -p flag when you deploy the sample app. The sample app manifest declares the path to the archive that cf push uses to upload the app files.

The example below shows the terminal output of deploying the pong_matcher_groovy app. cf push uses the instructions in the manifest file to create the app, create and bind the route, and upload the app. It then binds the app to the baby-redis service and follows the instructions in the manifest to start one instance of the app with 512 MB. After the app starts, the output displays the health and status of the app.

$ cf push pong_matcher_groovy -n groovy-ratpack-app
Using manifest file /Users/example/workspace/pong_matcher_groovy/app/manifest.yml

Creating app pong_matcher_groovy in org Cloud-Apps / space development as [email protected]...
OK

Creating route groovy-ratpack-app.cfapps.io...
OK

Binding groovy-ratpack-app.cfapps.io to pong_matcher_groovy...
OK

Uploading pong_matcher_groovy...
Uploading app files from: /Users/example/workspace/pong_matcher_groovy/app/build/distributions/app.zip
Uploading 138.2K, 18 files
OK
Binding service baby-redis to app pong_matcher_groovy in org Cloud-Apps / space development as [email protected]...
OK

Starting app pong_matcher_groovy in org Cloud-Apps / space development as [email protected]...
OK
-----> Downloaded app package (12M)
Cloning into '/tmp/buildpacks/java-buildpack'...
-----> Java Buildpack Version: 9e096be | https://github.com/cloudfoundry/java-buildpack#9e096be
       Expanding Open Jdk JRE to .java-buildpack/open_jdk_jre (1.3s)
-----> Uploading droplet (49M)

0 of 1 instances running, 1 starting
1 of 1 instances running

App started

Showing health and status for app pong_matcher_groovy in org Cloud-Apps / space development as [email protected]...
OK

requested state: started
instances: 1/1
usage: 512M x 1 instances
urls: groovy-ratpack-app.cfapps.io

     state     since                    cpu    memory           disk
#0   running   2014-10-28 04:48:58 PM   0.0%   193.5M of 512M   111.7M of 1G

Step 9: Test Your Deployed App

You’ve deployed an app to Cloud Foundry!

Use the cf CLI to review information and administer your app and your Cloud Foundry account. For example, you can edit the manifest.yml to increase the number of app instances from 1 to 3, and redeploy the app with a new app name and host name.

See the Manage Your Application with the cf CLI section for more information.

Sample App Step
To test the sample app, do the following:

1. To export the test host, run export HOST=SAMPLE_APP_URL, substituting the URL for your app for SAMPLE_APP_URL.

2. To clear the database from any previous tests, run:
curl -v -X DELETE $HOST/all
You should get a response of 200.

3. To request a match as “andrew”, run:
curl -v -H "Content-Type: application/json" -X PUT $HOST/match_requests/firstrequest -d '{"player": "andrew"}'
You should again get a response of 200.

4. To request a match as a different player, run:
curl -v -H "Content-Type: application/json" -X PUT $HOST/match_requests/secondrequest -d '{"player": "navratilova"}'

5. To check the status of the first match request, run:
curl -v -X GET $HOST/match_requests/firstrequest
The last line of the output shows the match_id.

6. Replace MATCH_ID with the match_id value from the previous step in the following command:
curl -v -H "Content-Type: application/json" -X POST $HOST/results -d ' { "match_id":"MATCH_ID", "winner":"andrew", "loser":"navratilova" }'
You should receive a 201 Created response.

Alternative Methods for Pushing Apps

Integrate a Plugin for Your Build Tool

Cloud Foundry provides plugins for Maven and Gradle. You can deploy and manage your apps using Maven or Gradle command-line syntax and configure security credentials.

For more information, refer to the Build Tool Integration topic.

Manage Your Application with the cf CLI

Run cf help to view a complete list of commands, grouped by task categories, and run cf help COMMAND for detailed information about a specific command. For more information about using the cf CLI, refer to the cf Command Line Interface (CLI) topics, especially the Getting Started with cf CLI v6 topic.

Note: You cannot perform certain tasks in the CLI because these are commands that only a Cloud Foundry administrator can run. If you are not a Cloud Foundry administrator, the following message displays for these types of commands: error code: 10003, message: You are not authorized to perform the requested action

Troubleshooting

If your application fails to start, verify that the application starts in your local environment. Refer to the Troubleshooting Application Deployment and Health topic to learn more about troubleshooting.

App Deploy Fails

Even when the deploy fails, the app might exist on Cloud Foundry. Run cf apps to review the apps in the currently targeted org and space. You might be able to correct the issue using the CLI, or you might have to delete the app and redeploy.

App Requires a Unique URL

Cloud Foundry requires that each app that you deploy have a unique URL. Otherwise, the new app URL collides with an existing app URL and Cloud Foundry cannot successfully deploy the app. You can fix this issue by running cf push with either of the following flags to create a unique URL:

  • -n to assign a different HOST name for the app.
  • --random-route to create a URL that includes the app name and random words. Using this option might create a long URL, depending on the number of words that the app name includes.