Deploying Ratpack apps to Cloud Foundry

This information walks you through deploying a Ratpack app to Cloud Foundry. If you experience a problem following the steps, check the Known Issues 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.

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 Cloud Foundry Command Line Interface (cf CLI)
JDK 1.7 or 1.8 for Java 7 or 8 configured on your workstation

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: (Optional) 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
Gradle	`build.gradle`	Gradle User Guide
Maven	`pom.xml`	Apache Maven Project Documentation

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, 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: (Optional) 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.

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: (Optional) 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.

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

Step 4: (Optional) Configure a Procfile

Use a Procfile to declare required runtime processes for your web app and to specify your web server. For more information, see the Configuring a Production Server topic.

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

Learn how to use the CLI to configure a Redis managed service instance for an app. You can use either the CLI or Apps Manager to perform this task. For more information about using Apps Manager, see About Apps Manager.

Cloud Foundry supports the following 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.

Creating a service instance

View managed and user-provided services and plans available to you by running:

cf marketplace

The example shows two of the available managed database-as-a-service providers and their offered plans: postgresql-10-odb 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

postgresql-10-odb  standalone, standalone-replica, general    PostgreSQL as a Service

rediscloud         30mb, 100mb, 1gb, 10gb, 50gb               Enterprise-Class Redis for Developers

Create a service instance for your app by running:
```
cf create-service SERVICE PLAN SERVICE-INSTANCE
```
Where:
- SERVICE and PLAN are chosen from the output of the previous step.
- SERVICE-INSTANCE is a unique name you provide for the service instance.

Run cf create-service rediscloud 30mb baby-redis. This creates a service instance named baby-redis that uses the rediscloud service and the 30mb plan, as the following example shows.

$ cf create-service rediscloud 30mb baby-redis
Creating service baby-redis in org Cloud-Apps / space development as [email protected]....
OK

(Optional) 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.

You can also bind a service using Apps Manager. For more information about using Apps Manager, see Adding and Binding services using Apps Manager.

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: (Optional) Configure the deployment manifest

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

See Deploying with application manifests for more information.

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

Enter your log in credentials, and select a space and org.

cf login -a API-ENDPOINT

Where API-ENDPOINT is the URL of the Cloud Controller in your TAS for VMs instance.

Note You must perform this step to run the sample app.

Step 8: Deploy the app

You must use the cf CLI to deploy apps.

From the root directory of your app, run the following command to deploy your application:

cf push APP-NAME -p PATH-TO-FILE.distZip

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.

The cf push command 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.example.com.

For example, cf push my-app creates the URL my-app.shared-domain.example.com.

The URL for your app must be unique from other apps that Cloud Foundry hosts or the push fails. 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 app directory, and run ./gradlew distZip to build the app. 1. Run cf push pong_matcher_groovy -n HOST-NAME to push the app. Example: cf push pong_matcher_groovy -n groovy-ratpack-app

This example is valid for cf CLI v6. In cf CLI v7 and onwards, the -n flag is not supported. The host name must be specified in the manifest, using the routes attribute.

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 following example 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. Note, this example is valid for cf CLI v6. In cf CLI v7 and onwards, the -n flag is not supported. The host name must be specified in the manifest, using the routes attribute.

$ 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

Use the cf CLI or About Apps Manager to review information and administer your app and your 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. For more information about using Apps Manager, see Using Apps Manager.

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.

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

1. 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.

1. 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”}’

1. 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.

1. 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.

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 Cloud Foundry Command Line Interface (cf CLI) topics, especially the Getting Started with cf CLI topic.

You cannot perform certain tasks in the CLI or About Apps Manager because these are commands that only an administrator can run. If you are not an administrator, the following message displays for these types of commands:

error code: 10003, message: You are not authorized to perform the requested action

For more information about specific Admin commands you can perform with Apps Manager, depending on your user role, see Getting Started with Apps Manager.

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 targeted org and space. You might be able to correct the issue using the CLI or About Apps Manager, 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 the --random-route flag to create a unique URL. Using --random-route to create a URL that includes the app name and random words might create a long URL, depending on the number of words that the app name includes.