Deploying to Jelastic

Jelastic is a cloud application platform designed specifically for servlets like Scalatra apps. Jelastic allows you to scale your app both horizontally (more instances) and vertically (more powerful instances). They offer a 2-week free trial, after which point their rates are among the best in the industry.

See scalatra-jelastic for a minimal and standalone project containing the example in this guide.

1. Register for an account.

Jelastic is a platform with many hosts to choose from. In this guide we’ll assume you’ve chosen LayerShift as your host.

2. Create an environment.

An “environment” in Jelastic-speak is a selection of a servlet container and any add-ons (like databases) that you may want.

On your management console click “Create environment.”

You need to choose an environment name that is unique across the entire Layershift host. We’ll proceed with the environment name scalatra-test, but yours will necessarily be different. The default of Tomcat 7 automatically scaling between 1 and 8 cloudlets is fine for us.

3. Set up a project.

  • Create a Scalatra project from the usual Scalatra giter8 template. Check out the the installation and first project guides if this isn’t familiar.
$ g8 scalatra/scalatra-sbt -b develop
$ cd [app root]
$ chmod u+x sbt
  • Install the Jelastic deployment plugin

Add the following line to project/plugins.sbt:

addSbtPlugin("com.github.casualjim" % "sbt-jelastic-deploy" % "0.1.4")
  • Configure the Jelastic deployment plugin

Add the following lines to buid.sbt. You will need to replace "scalatra-test" with the name of your environment.

seq(jelasticSettings:_*)

JelasticKeys.email in JelasticKeys.deploy := sys.env.get("JELASTIC_USERNAME").getOrElse(
sys error "Please export JELASTIC_USERNAME in your shell!"
)

JelasticKeys.password in JelasticKeys.deploy := sys.env.get("JELASTIC_PWD").getOrElse(
sys error "Please export JELASTIC_PWD in your shell!"
)

JelasticKeys.apiHoster := "app.j.layershift.co.uk"

JelasticKeys.environment in JelasticKeys.deploy := "scalatra-test"

publishTo := None

4. Configure your environment

You weren’t thinking of storing your username and password in version control, were you?

Open ~/.bash_profile on Mac, or ~/.bashrc on Linux, and add these lines, substituting your Jelastic username and password as appropriate:

export JELASTIC_USERNAME="you@you.com"
export JELASTIC_PWD="iluvyou"

Now close your shell and open a new one.

6. Deploy

With the project set up, your first deploy, and all future deploys, are insanely easy:

$ cd [app root]
$ ./sbt
> deploy

If all has gone well you’ll a ton of output. Here’s an abbreviated example:

> deploy
[info] Compiling 2 Scala sources to /Users/yuvi/Desktop/my-scalatra-web-app/target/scala-2.9.2/classes...
[info] Packaging /Users/yuvi/Desktop/my-scalatra-web-app/target/scala-2.9.2/my-scalatra-web-app_2.9.2-0.1.0-SNAPSHOT.war ...
[info] Done packaging.
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
[info] Jelastic session: 62e8x8c50adf7c46f3459f851617020ef8a53
[info] Upload of http://6e49611e3c2db05e830d2d4c9381469a.app.j.layershift.co.uk/xssu/rest/download/RDYYHFdvUVcIBl5JYldpTUAXDBQFHkQWCEE%2BGSgndlVHHkZZDwQBQmNTTEBI with size 22548400 succeeded.
[info] File registration for developer 25320 success
[info] Deploy success
[info] Stopping tomcat:
[info] Waiting for processes to exit..
[info] Waiting for processes to exit..
[info] Waiting for processes to exit..
[info] Sending the Tomcat processes a SIGTERM asking them to shut down gracefully..
[info] [  OK  ]
[info] --2012-12-16 22:44:39--  http://6e49611e3c2db05e830d2d4c9381469a.app.j.layershift.co.uk/xssu/rest/download/RDYYHFdvUVcIBl5JYldpTUAXDBQFHkQWCEE%2BGSgndlVHHkZZDwQBQmNTTEBI
[info] Resolving 6e49611e3c2db05e830d2d4c9381469a.app.j.layershift.co.uk... 207.58.158.90
[info] Connecting to 6e49611e3c2db05e830d2d4c9381469a.app.j.layershift.co.uk|207.58.158.90|:80... connected.
[info] HTTP request sent, awaiting response... 200 OK
[info] Length: 22547738 (22M) [application/octet-stream]
[info] Saving to: `/opt/tomcat//webapps/ROOT.war'
[info]
[info]      0K .......... .......... .......... .......... ..........  0% 41.6M 1s
[info]     50K .......... .......... .......... .......... ..........  0% 38.8M 1s
[info]    100K .......... .......... .......... .......... ..........  0% 60.6M 0s
[info]    150K .......... .......... .......... .......... ..........  0% 35.5M 1s
[info]  21900K .......... .......... .......... .......... .......... 99%  145M 0s
[info]  21950K .......... .......... .......... .......... .......... 99%  148M 0s
[info]  22000K .......... .........                                  100% 91.6M=0.3s
[info]
[info] 2012-12-16 22:44:52 (69.8 MB/s) - `/opt/tomcat//webapps/ROOT.war' saved [22547738/22547738]
[info]
[info] Starting tomcat: [  OK  ]
[info] Logged out of jelastic.
[success] Total time: 210 s, completed Dec 16, 2012 2:45:04 PM

7. Visit your website

Since we used the environment scalatra-test, the app is now live at http://scalatra-test.j.layershift.co.uk. As always, you will have to substitute your environment name into that URL.