Using boto3 with Jython

Few days back I had a requirement that I had to use boto3 with Jython. boto3 is AWS EC2 python SDK that you can use to work with various Amazon Cloud API’s. Jython is the JVM implementation of Python. We were packaging our Jython scripts and boto3 and its dependencies inside a JAR. boto3 and Jython work great together when you use them in a normal way i.e. when boto3 can load its data model files from file system. This does not work when you package your script and its dependencies inside a JAR as the model files are then not available on the filesystem but are available on the classpath. In this blog, I will show you how we used boto3 to overcome this limitation. Continue reading “Using boto3 with Jython”

DevFest Austria 2013 Talk : Thinking Beyond RDBMS — Building Polyglot Persistence Java Applications

Couple of weeks back I gave a talk at DevFest Austria event on how to use different nosql datastores with OpenShift.  You can view the video here.

Building Single Page Web Applications with Backbone.js, JaxRS, MongoDB, and OpenShift

Backbone.js is a mature, popular, and lightweight javascript library which aims to bring structure to your client-side code. The goal of backbone.js is to bring MVC, a software architecture pattern, to client side development.Actually, backbone.js is an MV framework where view is also responsible for controller logic as well. In this blog, we will build a simple social bookmarking application.

In brief, MVC is a programming design pattern for separating the different concerns of your application. The M corresponds to Model and is used to define domain object. The V corresponds to View and is responsible for display logic. Finally, the C corresponds to Controller and is responsible for user interactions and interactions between Views and Models.

You can find source code of the application here https://github.com/shekhargulati/getbookmarks. Backbone.js is used by Linkedin, Foursquare, Wunderkit, Groupon, etc to build complex applications. You can view the full list here.

Read full blog at https://www.openshift.com/blogs/building-single-page-web-applications-with-backbonejs-jaxrs-mongodb-and-openshift

How To Build Location-Aware Web Applications using HTML5 and MongoDB

We all use location aware applications in our day-to-day life. Applications like Foursquare, Facebook places, etc help us share our location (or places we visit) with our friends and family. Applications such as Google Local help us find out which businesses are near our current location. So, if we need a good coffee shop recommendation, we can ask Google Local to find us all the coffee shops near our location. This not only helps the customer, but also helps businesses reach the right audience and sell their products more effectively. It is a win-win situation for both consumers and businesses.

To build such an application , you need the geolocation of the user. According to Wikipedia, “Geolocation is the identification of the real-world geographic location of an object”. Until now, there was no standard way to find the location of a user in a web application. We could use an open source library like Google Gears to get the geo location of a user but this library is not under development anymore and should only be used with older browsers, which do not support W3C GeoLocation API. The W3C GeoLocation API is a specification that provides standard scripted access to geographical information associated with the hosting device. Geo Location support is not officially part of HTML 5 specification but people use it interchangeably and most commonly you will hear about GeoLocation APIs with respect to HTML5. This API provides an abstraction layer on top of how geolocation information of a user is gathered. All modern browsers support the GeoLocation API. The below table is taken from http://caniuse.com/#feat=geolocation.

Read full blog at https://www.openshift.com/blogs/how-to-build-location-aware-web-applications-using-html5-and-mongodb

How To Run Apache Tomcat 8 on OpenShift

OpenShift PaaS gives developers the ability to try out new unsupported frameworks, programming languages, and servers. Today, while learning about WebSockets I learned that the current development version of Apache Tomcat i.e. version 8, has support for JSR356. JSR356 provides standard Java API for WebSockets. Although Apache Tomcat 7 provides support for WebSockets, it uses its own proprietary API. So, in order to test the JSR356 standard based WebSockets support in Apache Tomcat 8, I decided to give it a try. However, rather than installing Apache Tomcat 8 on my local development machine, I decided to install it on OpenShift.

Read full post at https://www.openshift.com/blogs/how-to-run-apache-tomcat-8-on-openshift

OpenShift Rails QuickStart

  1. Create a Ruby 1.9 application
    rhc app create -a railsdemo -t ruby-1.9
    
  2. After running the command railsdemo folder will get created in your directory. Run the command shown below. This will generate rails code in the railsdemo folder.It will ask you whether you want to override, say yes.
    rails new railsdemo
    
  3. Next run commands shown below
    cd railsdemo
    bundle install
    rails generate controller home index
    rm public/index.html
    
  4. Add the following route to config/routes.rb:
    root :to => "home#index"
    
  5. Generate Post entity with fields as shown below
    rails generate scaffold Post name:string title:string content:text
    
  6. Add Database support by uncommenting following lines from .openshift/action_hooks/deploy script
    pushd ${OPENSHIFT_REPO_DIR} > /dev/null
    bundle exec rake db:migrate RAILS_ENV="production"
    popd > /dev/null
    
  7. Add mysql cartridge
    rhc cartridge add -a railsdemo -c mysql-5.1
    
  8. Update config/database.yml
    production:
      adapter: mysql2
      encoding: utf8
      database: <%=ENV['OPENSHIFT_APP_NAME']%>
      pool: 5
      host: <%=ENV['OPENSHIFT_MYSQL_DB_HOST']%>
      port: <%=ENV['OPENSHIFT_MYSQL_DB_PORT']%>
      username: <%=ENV['OPENSHIFT_MYSQL_DB_USERNAME']%>
      password: <%=ENV['OPENSHIFT_MYSQL_DB_PASSWORD']%>
      socket: <%=ENV['OPENSHIFT_MYSQL_DB_SOCKET']%>
    
  9. Add gem in Gemfile
    gem 'mysql2'
    
  10. Add, Commit, and Push the Code
    git add .
    git commit -a -m "Initial setup"
    git push
    
  11. Finally you can view the application running at http://railsdemo-domainname.rhcloud.com and you can create new posts at http://railsdemo-domainname.rhcloud.com/posts

Deploy war on tomcat running on OpenShift

In this short blog, I will show you how you can deploy war file on Tomcat running on OpenShift. For Java, OpenShift supports three deployment options – JbossAS-7, JBossEAP-6, and JBossEWS-1.0 or Tomcat. In all of the three options it supports both binary deployment (war file) and source code deployment(maven project). I have talked about how you can do source code deployment on tomcat in my previous blog.

Step 1: Sign up for an OpenShift Account

If you don’t already have an OpenShift account, head on over to the website and signup with promo code ews. It is completely free and Red Hat gives every user three free Gears on which to run your applications. At the time of this writing, the combined resources allocated for each user is 1.5 GB of memory and 3 GB of disk space.

Step 2: Install the client tools on your machine

Note: If you would rather watch a screencast of this step, check out the following videos where I demo how to install the client tools.

Windows

Linux Ubuntu

Linux Fedora

OSX

The OpenShift client tools are written in a very popular programming language called Ruby. With OSX 10.6 or later and most Linux distributions, ruby is installed by default so installing the client tools is a snap. Simply issue the following command on your terminal application:

sudo gem install rhc

Step 3 : Setting up OpenShift

The rhc client tool makes it very easy to setup your openshift instance with ssh keys, git and your applications namespace. The namespace is a unique name per user which becomes part of your application url. For example, if your namespace is cix and application name is bookshop then url of the application will be https://bookshop-cix.rhcloud.com/. The command is shown below.

rhc setup -l openshift_login

Step 4 : Creating Tomcat Application

After installing the client tools and setting up OpenShift account, next step is to create the bookshop application. This is a very simple Spring JPA application which has only one entity called Book. So, a user can do CRUD operations on book entity. To create a book entity, execute the command shown below.

rhc app create -a bookshop -t jbossews-1.0

This will create an application container for us, called a gear, and setup all of the required SELinux policies and cgroup configuration. OpenShift will also setup a private git repository for you and propagate your DNS out world wide.

Step 5 : Download the WAR file

Because we are doing binary deployment in this blog, we have to remove the src folder and pom.xml file from git repository and add the war file.

git rm -rf src/ pom.xml
git commit -am &amp;quot;removing default files&amp;quot;

Next download the war file from http://bookshop-demo.googlecode.com/files/ROOT.war and copy the war file in webapps directory. The name ROOT for war makes sure that the application is accessible at the root context i.e. http://bookshop-cix.rhcloud.com/.

git add .
git commit -am &amp;quot;committing bookshop war file&amp;quot;

Step 6 : Pushing the code to OpenShift

Finally push the code to OpenShift using git.

git push

The git push command upload the binary to the application gear and runs the action hooks specified in .openshift/action_hooks folder.