Complete Tutorial: Webpy + Apache + mod_wsgi on Ubuntu

There has been plenty of tutorials and blogs on how to configure webpy application with apache and mod_wsgi, but none of them turned into successful one. After 2 days of research i have found the solution and decided to write a blog on the same. Hope it will be useful for others.

In the future, I hope to update this post to also include a complete list of steps for getting setup with python’s webpy over lighttpd.


1. Install web.py

1.1. Install webpy with apt-get

sudo apt-get install python-webpy

1.2. Install webpy using easy_install using python setuptools 

1.2.1. Install python setuptools (easy_install)

# 1.2.1.1. Using apt-get:

sudo apt-get install python-setuptools
# 1.2.1.2. Manually retrieving easy_install from the web using wget

wget http://peak.telecommunity.com/dist/ez_setup.py
sudo python ez_setup.py

# 1.2.2. Now get the web.py egg using python’s easy_install
# This will put the python ‘web’ module in your python environment path

sudo easy_install web.py

1.3. Install webpy straight from git

# Or, get webpy straight from git

git clone git://github.com/webpy/webpy.git ln -s `pwd`/webpy/web .

2. Write Your Web.py App

Choose a directory where you would like your web.py python application to live. If my username is ‘mek’ and I want to name my project ‘project’, I might make a directory /home/sajee/project.

2.1. Make a directory for your web.py app to live
# Replace the word project in the path below with your desired project name

mkdir ~/project
cd ~/project # move into the project directory you have created

2.2. Create your application file using web.py
# this will create our application file ~/project/main.py

touch main.py
2.3. Open your application with your favourite editor

# Substitute “emacs -nw” with an editor of your choice: vim, nano, etc

emacs -nw main.py

2.4. Paste the following in your app file and save

import web

app_path = os.path.dirname(__file__)
sys.path.append(app_path)

if app_path: # Apache
os.chdir(app_path)
else: # CherryPy
app_path = os.getcwd()

urls = (
'/(.*)', 'hello'
)
# WARNING
# web.debug = True and autoreload = True
# can mess up your session: I've personally experienced it
web.debug = False # You may wish to place this in a config file
app = web.application(urls, globals(), autoreload=False)
application = app.wsgifunc() # needed for running with apache as wsgi
class hello:
def GET(self, name):
if not name:
name = 'World'
return 'Hello, ' + name + '!'

if __name__ == "__main__":
app.run()

2.4. (Optional) Setup static directory for imgs, css, js, etc
# Having a static directory allows you to serve static content without
# your webpy application trying to steal focus and parse the request
# This is especially important using the default CherryPy server.
# We’ll also handle this case in our apache config within:
# /etc/apache2/sites-available

mkdir ~/project/static

3. Install Apache2

3.1. Install apache and wsgi dependencies

sudo aptitude install apache2 apache2.2-common apache2-mpm-prefork apache2-utils libexpat1 ssl-cer
# I like to also install python-dev (optional) to make sure I have
# python’s latest support files

sudo apt-get install python-dev
3.2. Install apache mod_wsgi and enable mod_wsgi + mod_rewrite

sudo aptitude install libapache2-mod-wsgi
sudo a2enmod mod-wsgi;sudo a2enmod rewrite
Need help troubleshooting your apache/mod_wsgi installation?

4. Configure Apache2 With Your App

In the following steps, replace ‘project’ with the name of your project

4.1. Make Apache Directories for your project

sudo mkdir /var/www/project
sudo mkdir /var/www/project/production
sudo mkdir /var/www/project/logs
sudo mkdir /var/www/project/public_html
4.2. Create Symlinks
Creating symlinks to your project files is an important covention as, if there is a problem with one of your code bases, you can simply change your symlink to a stable codebase without having to modify your apache configuration.

ln -s ~/project/ production
ln -s ~/project/static public_html # If you created the static directory in step 2.4.
4.3. Replace you /etc/apache2/sites-available/default with:

ServerAdmin admin@project.com
DocumentRoot /var/www/project.com/public_html/
ErrorLog /var/www/project.com/logs/error.log
CustomLog /var/www/project.com/logs/access.log combined

WSGIScriptAlias / /var/www/project.com/production/main.py
Alias /static /var/www/project.com/public_html
AddType text/html .py
WSGIDaemonProcess www-data threads=15
WSGIProcessGroup www-data


Order deny,allow
Allow from all
Options +FollowSymLinks
Options -Indexes

4.4. Change the group and owner of files requiring write access to apache’s www-data
Careful in this step to only change the group and owner of directories or files that will require write access.

sudo chgrp -R www-data
sudo chown -R www-data

5.Try to run!

sudo /etc/init.d/apache2 restart # Open your browser and visit the url: http://localhost or 127.0.01

You will see Hello World on the browser.

I love Visual Studio Code

I've been a .Net developer since the beta days of .Net 3.0, Now i find myself doing less and less coding related with .Net related stuffs. However, the new strategy from Microsoft  encouraged all the developers including me to once again start doing some .Net work from time to time.
One of the highlighting tool among them was the Visual Studio Code.


Sublime text has been my favorite text editor all these time.When i downloaded it and looked at the first time my impression was nothing more than a plain editor with very little added value. Before VS code I have tried all popular editors - Sublime, Atom, Brackets etc. After trying it for few weeks now I feel developers  have everything they need .

Some of the highlights of VS Code are as follows,

• Default integrated git system is really awesome.
• Powerful debugging option.
• Very smart code completion.
• Huge list of Languages Support
• Multi panel for side by side editing
• Always-On IntelliSense
• Debugging support
• Peek Information like grammer correction
• Command Palette

Choice of editor is a personal preference. If you like an lightweight IDE environment that's cross platform, you might enjoy VS Code. Give it a try, you will definitely love it.

Angular Directives with D3

It's been exactly 2 years since i started to learn Angular and it's sad that i dint write even a single blog on the same. Finally decided to start a series on the same topic. AngularJS is a JavaScript MVC Framework that integrates two-way data binding, web services, and build web components. There are enough number of blogs and tutorials to follow on the same.

The current product which i am working is a data visualization tool which is built on AngularJS  and has many visualization  been integrated with D3.js.

In this blog, will be describing how to build a directive using d3.js and angular.

Directive is very powerful feature of AngularJS. It easily wired up with controller, html and do the DOM manipulations.

Building a Decomposition Force directed d3 directive:

 App.directive('forceGraph', function() {  
   return {  
     restrict: 'EA',  
     transclude: true,  
     scope: {  
       chartData: '='  
     },  
     controller: 'hierarchySummaryCtrl',  
     link: function(scope, elem, attrs) {  
       var svg;  
       elem.bind("onmouseover", function(event) {  
         scope.svg = svg;  
         console.log("hierarchy svg", scope.svg);  
         scope.$apply();  
       });  
       scope.$watch('chartData', function(newValue, oldValue) {  
         if (newValue) {  
           scope.draw(newValue.data,newValue.id);  
         }  
       });  
       scope.draw = function(rootData,divID) {  
         var width = 400,  
           height = 320,  
           root;  
         var force = d3.layout.force()  
           .linkDistance(80)  
           .charge(-120)  
           .gravity(.05)  
           .size([width, height])  
           .on("tick", tick);  
         var divid = "#" + divID;  
         d3.select(divid).selectAll("*").remove();  
         svg = d3.select(divid)  
           .append("svg").attr("viewBox", "0 0 400 400")  
           .attr("width", '100%')  
           .attr("height", '100%');  
         var link = svg.selectAll(".link"),  
           node = svg.selectAll(".node");  
         root = rootData;  
         update();  
         console.log(svg);  
         scope.setSvg(svg[0][0].innerHTML);        
         function update() {  
           console.log(nodes)  
           var nodes = flatten(root),           
           links = d3.layout.tree().links(nodes);          
           var nodes = flatten(rootData),           
           links = d3.layout.tree().links(nodes);             
           force.nodes(nodes)  
             .links(links)  
             .start();  
           // Update links.  
           link = link.data(links, function(d) {  
             return d.target.id;  
           });  
           link.exit().remove();  
           link.enter().insert("line", ".node")  
             .attr("class", "link");  
           // Update nodes.  
           node = node.data(nodes, function(d) {  
             return d.id;  
           });  
           node.exit().remove();  
           var nodeEnter = node.enter().append("g")  
             .attr("class", "node")  
             .on("click", click)  
             .call(force.drag);  
           nodeEnter.append("circle")  
             .attr("r", function(d) {  
               return Math.sqrt(d.size) / 5 || 4.5;  
             });  
           nodeEnter.append("text")  
             .attr("dy", ".25em")  
             .text(function(d) {  
               return d.name + ", Count: " + d.size;  
             });  
           node.select("circle")  
             .style("fill", color);  
         }  
         function tick() {  
           link.attr("x1", function(d) {  
               return d.source.x;  
             })  
             .attr("y1", function(d) {  
               return d.source.y;  
             })  
             .attr("x2", function(d) {  
               return d.target.x;  
             })  
             .attr("y2", function(d) {  
               return d.target.y;  
             });  
           node.attr("transform", function(d) {  
             return "translate(" + d.x + "," + d.y + ")";  
           });  
         }  
         function color(d) {  
           return d._children ? "#FFEB3B" // collapsed package  
             :  
             d.children ? "#F44336" // expanded package  
             :  
             "#D32F2F"; // leaf node  
         }  
         // Toggle children on click.  
         function click(d) {  
           if (d3.event.defaultPrevented) return; // ignore drag  
           if (d.children) {  
             d._children = d.children;  
             d.children = null;  
           } else {  
             d.children = d._children;  
             d._children = null;  
           }  
           update();  
         }  
         // Returns a list of all nodes under the root.  
         function flatten(root) {  
           var nodes = [],  
             i = 0;  
           function recurse(node) {  
             if (node.children) node.children.forEach(recurse);  
             if (!node.id) node.id = ++i;  
             nodes.push(node);  
           }  
           recurse(root);  
           return nodes;  
         }  
       };  
     }  
   };  
 });  

My Repository With the sample

Digging into BigData with Google's BigQuery

Well, i was one of the speaker at Colombo Big Data Meetup which was held yesterday and i spoke about Google's bigquery. Hence i have decided to write a blog on that so that you could get benefited if you are a BigData Fan.

What is Big Data?

There are so many definitions for Big Data , let me explain what does it really mean? In the near feature, every object on this earth will be generating data including our body.We have been exposed to so much information everyday.In vast ocean of data, complete picture of where  we live where we go and what we say, its all been recorded and stored forever.More data allows us to see new , better different things.Data in the recent times have changed from stationary and static to fluid and dynamic.we rely a lot on data and thatch is  major part of any business.we live in a very exciting world  today, a world where technology is advancing at a staggering pace, a world data is exploding, tons of data being generated. 10 years before we were measuring data in mega bytes, today we are talking about data which is in petabyte size, may be in few years we are going to reach zetabyte era, that means the end of English alphabets.Does it means the end of Big Data? .No . If you have shared a photo or post or a tweet on any social media,You are one of them who is generating data, and you are doing it very rapidly.

More than 100 thousand tweets in 60 seconds are generated , more than 7 million posts have been posted on Facebook, before you read this sentence.So the data is generated faster  than you could ever think before.Big data and analysis has exploded recently but there is a barrier. That barrier is indeed it needs lot of money resources and time to setup the infrastructure.Also it needs skillful people to make it all happen. so google solves all these big query.Big query,One of the products of google cloud platform that allows us to easily work with big data.It is google's fully managed data analysis service offering in the cloud. It enables super fast analysis.Easily store and analyse big data in google infrastructure.

Lets get familiar with the components.
 Projects are going to be the top level item inside the google cloud platform. Project contains, users authentication billing information and that is where data sets are going to live.
 Data set is really a container for tables.Access controllers cannot be done on tables so that they are don  through projects and data sets.Project contains data sets, data sets contains tables.
 Tables where the data lives
 Jobs are going to be asynchronous process that run on the background to load, export and to execute large queries.

Lets see How to use google cloud platform for big data solution.Architecture is divided in to two workflows named data workflow and visualization workflow.We need to get our source data into big query using any ETL tool and pipe into google cloud storage. Extract it from source and de normalize it,Biquery likes less joins the better .we can use hadoop clusters running on computers to do many pre processing and transforming data.once its in bigquery its all about visualization. Most of the use cases are log analysis which is used to analyse application behavior and user behavior in order to improve the system.Retail forecast - the more data, business has the more accurately they can predict product sales for the next month,that allows them to plan better. Lets see how we can use big query to analyse lots of data in very short time they handle the infrastructure and we can just simply focus on getting our data and analyse it.

Google handles Big Data every second of every day to provide services like Search, YouTube, Gmail and Google Docs.Can you imagine how Google handles this kind of Big Data during daily operations? How they are doing it?

As an example, let’s consider the following SQL query, which requests the Wikipedia® content titles that includes numeric characters in it:

select count(*) from publicdata:samples.wikipedia where REGEXP_MATCH
(title, ‘[0-9]*’) AND wp_namespace = 0;

Notice the following:
• This “wikipedia” table holds all the change history records on Wikipedia’s article content and consists of 314 millions of rows – that’s 35.7GB.

• The expression REGEXP_MATCH(title, ‘[0-9]+’) means it executes a regular expression matching on title of each change history record to extract rows that includes numeric characters in its title (e.g. “United States presidential election, 2015”).
• Most importantly, note that there was no index or any pre-aggregated values
for this table prepared in advance.

Dremel can even execute a complex regular expression text matching on ahuge logging table that consists of about 35 billion rows and 20 TB, in merely tens of seconds. This is the power of Dremel; it has super high scalability and most of the time it returns results within seconds or tens of seconds no matter how big the queried data set is.

Two core technologies which gives Dremel this performance:

1. Columnar Storage. Data is stored in a columnar storage fashion which
makes possible to achieve very high compression ratio and scan throughput.
2. Tree Architecture is used for dispatching queries and aggregating results
across thousands of machines in a few seconds.

Columnar Storage
Dremel stores data in its columnar storage, which means it separates a record into column values and stores each value on different storage volume, whereas
traditional databases normally store the whole record on one volume.

• Traffic minimization. Only required column values on each query are scanned and transferred on query execution. For example, a query “SELECT top(title) FROM foo” would access the title column values only. In case of the Wikipedia table example, the query would scan only 9.13GB out of 35.7GB.
• Higher compression ratio. One study  reports that columnar storage can  achieve a compression ratio of 1:10, whereas ordinary row-based storage can compress at roughly 1:3. Because each column would have similar values, especially if the cardinality of the column (variation of possible column values) is low, it’s easier to gain higher compression ratios than row-based storage. Columnar storage has the disadvantage of not working efficiently when updating existing records. In the case of Dremel, it simply doesn’t support any update operations.

Tree Architecture
One of the challenges Google had in designing Dremel was how to dispatch queries and collect results across tens of thousands of machines in a matter of seconds. The challenge was resolved by using the Tree architecture. The architecture forms a massively parallel distributed tree for pushing down a query to the tree and then aggregating the results from the leaves at a blazingly fast speed.

The tree architecture also enables multiple queries to run at once within the tree, which lets
different users share the same hardware.You might have heard of hadoop map reduce mechanism,
so what is the difference between mad reduce and bigquery

Bigquery can be integrated in to applications in so many ways, Following are the integrations supported by bigquery,

Rest API (SDK) 

1. Google Spreadsheet
2. Web application

Interfaces for query:

1. Command Line Tool
2. Bigquery UI

Connectors for excel

Tools for Big Data Solution:

As mentioned in the above architecture following tools can be used for managing the data ingest and visualization.

Tableau,BIME and DigIn for analysing and creating visualizations for various insights. Talend and SQLStream for the ingestion of data into bigquery from various data sources.

Nothing comes free, since google handles the infrastructure there is bit of a cost involved and the pricing goes as below.

Once you have decided to use bigquery there are certain things you need to know before using for optimizations and less cost.

Do not use queries that contains Select * , which is going to execute entire dataset and hence it will result in a high cost.

Since bigquery stores values in nested fields it is always better to use repeated fields.

Store in multiple tables as possible since it is recommended not to have JOINS

Bigquery also supports extensions such as ebq and dry run to encrypt the data and for executing the query to actually check how much resources that actual query is going to consume, which makes lot of developers and data analysts job easy.

I will be writing two separate blogs in the coming days on how to integrate with Bigquery and How to ingest the data into bigquery.

You can find the slides of the presentation from here

Business Intelligence Solution for an Insurance Industry

Business Intelligence and It's impacts:

Hello! I am back, after what I realized was my first extended blog break in four years. This time something technical, which is very much relevant to the product which i am currently working on. First of all, what is Business Intelligence?  It is the process, tools and infrastructure for generating insights from raw data is collectively called Business Intelligence.

Every organization generates data as part of its operations. Every organization also has access to some form of external data. But in order to analyze and take informed decisions, the data has to be processed and turned into information, and the information has to be presented in a meaningful way to be able to identify patterns or to see key performance indicators (KPIs), and thereby generate insights out of the information.          

This blog mainly describes the importance of BI in an insurance industry since i have to do my final project  where a BI solution can be used and come up with a solution with a collection of tools.

BI Solution for an Insurance Industry:

With rising globalization and growth, Business intelligence has become important for many firms. Business Intelligence solutions help these firms to transform into a dynamic enterprise through actionable intelligence. One of the important sector in this modern world is the insurance firms. In terms of technology, insurance companies are generally not at the forefront of technology and their systems are way behind. I have taken this domain as my project with some of the open source and commercial business intelligence tools that could help this sector.

The Organization i picked was HNB assurance PLC, it is a leading Sri Lankan Insurance corporation which provides Life Insurance solutions for Sri Lankan citizens.

The following are the Analysis that i have performed on the sample data that i have collected.

Classification of their Customer profiles using Decision tree and plotted in GeoMaps
Sentimental analysis of the company's Facebook Page
Various insights for their Insurance Claims
Sales forecasting – Dashboard

BI Tool that i have used : 

DigIn 

DigIn is the only true end-to-end analytics platform that allows you to easily visualize your structured and unstructured data in one place.Also it has On-demand data ingest capabilities and in-memory caching allows anyone to access data from anywhere at anytime from any device.

Conclusion: 

Use of business intelligence and analytic tool/solution is very vital for any insurance company wanting to succeed in an increasingly competitive industry. The ability to turn large volumes of raw data into actionable insights represents a significant value proposition for these businesses. These insights can be priceless in terms of the limitless opportunities they can unearth across the business with the help of social media analytics. Hope, This BI tool that i have suggested for this organization is a wonder not a
blunder.

You could find the slides that i have used for my presentation Here

DuoSoftware, Not Just another Software Company

Time has gone extremely fast, and I can still recall the day that I joined Duo. I can safely say that Duo is an awesome place to work at since I have had the opportunity to work with awesome, highly motivated people who loves the company. I never had much trouble with work life balance as I only worked more when I felt like it, rather than someone telling me to do. It truly is a different experience working for a Product Company which gives you an environment (Innovation engine) and Core focus on developing cutting-edge components.

Unlike most of the top IT firms in Sri Lanka, Duo gives  much importance to innovation and out of the box thinking. If you have something new and substantial to offer, trust me you are going to go a long way. It is a great place to start your career. Work culture is very positive and is full of energy. Talents are recognized and appreciated. Most importantly, one of the places which gives importance to work life balance!

Why I think it’s a great place to work?

Flat Hierarchy and Freedom of Ideas:

One of the things I love about Duo Software is that there's no sense that management is hiding somewhere making decisions and then condescendingly telling you what to do without listening to input. From CEO to the person who provides tea is constantly asking for input from everyone in the company and is available for discussing where we should go. It is a company, still at a size where you can get to know everybody and things still feel like a family. And it's exciting to watch the company itself evolve and grow.

Great Learning:

Duo Software has a lot of smart, hard-working people. The best engineers I have ever had the privilege of working with. For developers out there it’s a company that uses “GoLang”, a fun new language, as well as Couch Base, Redis, AngularJS and a range of other cool new technologies that will be good to know for the rest of your career.

Here at Duosoftware,

“Developers don't need dress code,

                                          They do write best code!”

Awesome office:

Some heavy metal music to keep you awake, a pool table which is free to be used by the team whenever they like, a reception hall with a pretty receptionist, a group of crazy people from different places belonging to one family. What more  could you ask for?

More Opportunity and Responsibility:

As of my knowledge, DuoSoftware is producing an exciting product that is constantly evolving and exploring the cutting edge, thereby a developer can become a full professional stack developer.

The Best “CEO”:

Last but not the least, one of my inspirations Mr.Muhunthan Canagey. As an aspiring tech entrepreneur, I think his best asset and what led him to success was being optimistic. He sees the problem in many perspectives and he thinks of solving the problem in many dimensions. An outstanding human being, that any employee  would be proud to to have as CEO.

Best memories you would have when you are at Duosoftware:


*Yes at Duo Software we don’t miss an opportunity to celebrate whether it's a birthday or it’s someone's first salary in office.Duo Software boasts of an overloaded fridge to provide drinks (only cool) at work, and a pool table to use and to a take your mind off work and colleagues do much more than computer games to relax and bond.Late night working  with colleagues during critical times is always a fun experience and takes the stress away from pressure situations.

There is a saying “Love your job but don't love your company, because you may not know when your company stops loving you” which exactly tells the current corporate world. But if you are at Duo Software, you will never stop loving the Company as it is a company that gives you so much more than mere work experience in return.

Finally, my journey with Duo Software is remarkable, and I hope the upcoming days will be equally fulfilling and challenging, towards my next goal. I hope this blog will also serve some help to new members of team Duo  or laterals willing to join Duo Software.