Fountain of Wisdom

Batch convert PSD to PNG

2013-01-17T03:31:00.002-08:00

Recently I needed to convert a bunch of PSDs to PNGs.
Here's how I did it:

I installed ImageMagick along with the dev packages.

Ran the follow command and got the job done.
mogrify -format png *.psd

More info here: http://www.noob2geek.com/how-to/batch-convert-images-using-imagemagick/

Choosing technology stack for your Next Big Idea? Here's help...

2012-12-14T22:18:00.001-08:00

Listed are some common decisions that you need to take when you are planning to develop a new web application along with hints at helping you in choosing the right vendors and frameworks:

1. Hosting:

Heroku - Easy deployment + scalability and high availability + plug and play services. But least custom control.

Engineyard - Ease of deployment + Amazing customer service + root access.

Linode - Cheaper than many + variety of server templates to start with + root access. But complicated.

Amazon EC2 (self-managed) - We configure the environment from scratch. Maximum control and easily scale-able but the onus of server management falls on you.

These are just a few common options. I'm sure there are many more...
You can check out this white paper to understand the advantages of using a Platform-as-a-service over self-managed servers. It helps you in reducing the Total-Cost-of-Ownership (TCO). It feels like having the best server engineers dedicated to making your servers more secure and reliable.

2. Monitoring:

New Relic is the de-facto for monitoring the server, identifying bottlenecks and setting up alerts when the performance falls below some threshold. Highly recommended.

3. Data persistence:

Relational Database v/s No SQL. Here's a related discussion and mongodb faq

Possibility of an application utilizing both Relational database and No SQL as a hybrid persistence.

4. Choice of Application Frameworks:

Depends upon the technical comfort of the development team and sometimes on the management red-tape involved in the decision making process.

Ruby on Rails - Rapid and Agile web application development. Vibrant open source community with plugins for just about anything that you can imagine. Any CPU intensive operations are generally extracted into native code (say written in C) with a ruby wrapper around it.

Java/.net - Long list of active enterprise applications to support the credibility.

Node.js - This a new contender in the server-side application development technologies. Best suited for serving high volumes of requests with minimal hardware *conditions applied.
Using Node.js, LinkedIn went from running 15 servers with 15 instances on each physical machine to just 4 instances that can handle twice the traffic. More about it here.

An application can be built on Service Oriented Architecture - where the data can be processed and served by one or many server written in different technologies while being consumed by a modern client-side framework like AngularJS and BackboneJS.

Surviving the management landmines in an Agile environment

2012-12-06T01:43:00.005-08:00

Sounds familiar?

This post aims to give YOU - The zen developer / leader - some hints at surviving the management landmines in an Agile environment.

Without implying that your boss is incompetent, the fact is that the Agile way of project management is new and there are a lot of misconceptions lingering around. Here are some things you might hear your boss say and some hints about how to respond to them.

"Agile is flexible." - implying - We can pull people in and out of the teams and can keep changing the requirements at any point of time.

Make it immediately clear that the features and requirements are flexible and can keep changing. But the team and the requirements do get locked in for the duration of an "Agile Sprint" which generally varies from 2-4 weeks.

"There were 10 features out of which 3 could not be delivered in the sprint. You failed!"

Predicting software delivery has never been a walk in the park and when it comes to predicting the delivery in a short period of time it can only mean risks and uncertainties.

"At regular intervals, the team reflects on how
to become more effective, then tunes and adjusts
its behavior accordingly." - Agile Principles

Agile is not magic. An Agile team understands its velocity, improves efficiency and evolves over time. This results in better estimates in future but only when given some stability to the team. Too many new additions (or subtractions) to the team? Make the risks clear to your boss and assure stability over time.

"Its only two days to code delivery date. We don't need automated unit tests. Just write the code, make the UI presentable and we're done."
Agile and BDD/TDD go hand-in-hand. If you don't write tests, the future iterations become unpredictable. In my experience, strict adherence to BDD / TDD helps you deliver faster (once you get a hang of it) or with little deviation from the original estimates. Make your boss aware of the future risks that it would pose to the project deliveries if you do otherwise.

"You wanted three people. Take this guy and these two interns and deliver the project"
Agile assumes that the team is made up of professionals who are highly motivated towards meeting the goals. You may have a few inexperienced people in the team but that arrangement works best if you can pair them up with some highly experienced developers for a few sprints. Make your boss aware that Agile is not a short-term quick fix but a way of delivering quality software in predictable time frames but the team might take a few sprints for it to happen.

Can you recall similar conversations with your boss? I would love to hear about them in the comments.

Ruby on Rails is for Toy Apps. Wtf!

2012-11-14T02:54:00.000-08:00

I recently met a guy who told me that "We are making our product in java. I've a great software architect (who develops in java) who told me that Ruby on Rails is for data driven toy applications but when it comes to serious business apps, we use java".

This is not the first time I'm hearing this... So many java developers have been spreading this propaganda that Ruby on Rails applications are slow which is non-sense because the only thing that makes an application slow is the nut coding it.

I've coded in C++, MFC, java and .net before I started coding in Ruby and I've seen many obvious benefits that Ruby and Ruby on Rails gives to the coder and the code -

1. Readability

2. A long list of plugins - Gems we call them. Just think of a use case and there's a already a gem which does that.

3. Speed of development - You start seeing considerable progress within half an hour.

4. Agility - Ruby on Rails has agility at its core given the features of data migrations and built-in unit test suite.

I don't have the stats around it, but I haven't seen any developer community more paranoid about TDD and BDD than ruby community which is the foundation of Agile development and quality code.

Heard that Ruby is slower than Java?

1. There is JRuby - the java implementation of Ruby - it bridges the gap.

2. Did you know that most of the heavy lifting is done in C? And that ruby makes it very easy to wrap in your native extensions as Ruby gems?

So, the next time your java engineers tell you that Ruby / Ruby on Rails is for toy apps. Well, say wtf!

Designing the button - Sign in with Linkedin - using Twitter Bootstrap

2012-10-18T21:21:00.000-07:00

in® Sign in with Linkedin

<a href="/third_party_authentication/linkedin" class="btn btn-info btn-large" style="padding-top:3px;padding-bottom:3px;">
  <strong>
    <span style="font-size: 22px">in<span style="font-size:5px">®</span></span>
    <span style="height: 40px;margin: 0 9px;border-right: 1px solid lightgray;border-left: 1px solid slategray;margin-left: 3px"></span>
    Sign in with Linkedin
  </strong>
</a>

How to create Products that Sell

2012-09-15T00:23:00.002-07:00

Step 1. Maintain simplicity

A phone needs to be able to make clear calls, a toaster should toast bread, an iPod plays songs.

Its OK not to satisfy everyone on the planet. The biggest reason why many products (mostly consumer software products) die is that they get into this cycle of adding more and more features to the product while the core feature stays the same. It becomes bulky, feels complicated and slowly becomes unusable to everyone.

Does that mean you should just throw away your million dollar add-on? Absolutely not! You can make a new product out of it for the specific target audience. You would not only be able to focus better, but also allow the users feel at home. You can of-course design your related products to snugly fit together if that makes sense.

Step 2. Generate the Craving

The Eye Candy

We all have an innate sense of beauty. You might not be able to put it in words but you just know when something is beautiful.
The product should be likable down to the very fine details.

Take the case of Apple. Their products are an eye candy from the body design down to every pixel on the software that runs on it. Everything looks just perfect. Its sexy and you know it.

Advertising

Watch Rory Sutherland: Life lessons from an ad man
"When you place a value on things like health, love, sex and other things, and learn to place a material value on what you’ve previously discounted for being merely intangible … you realize you’re much, much wealthier than you ever imagined." (Rory Sutherland)

Step 3. Provide Reassurance

We all know that people buy impulsively but what few understand is that most people often do seek re-assurance before making a purchase.

While the warranty / timely service is all very important and influences the decision, the fan-boys play a subtle part. Blogs harping about the success of apple, how Apple is selling the most iPhones in the US, how 90% of internet traffic comes from iPads (based on an unreliable source of statistics and assuming that iOS implies iPad). Since, so many people are happy with it (so you have read), it must be good right?

Later when you come home after buying a new iPad for 500$, you wouldn't want to be reading a blog saying "iPad sucks because it can't multi-task" on your iPad would you?

Make it or fake it, get the ball rolling. Once people see many people writing about the same topic, many others would jump in.

What's your estimate on your project?

2012-09-12T01:35:00.000-07:00

The legend has it that in a big corporate meeting the youngest guy in the team stood up against the Senior Director of their business unit over his belief that "Every software is unique and you can't estimate its delivery dates. If you do then if you don't meet the dates, its disheartening for someone working day and night to achieve the goal. So why estimate in the first place? Just press the pedal to the floor and deliver at the earliest.".

But there was a mutual consensus at the end of the meeting that over a period of time, on an average, similar software solutions take similar time to code. Which could only mean that it was possible...

The Director was kind and patient. He later met this junior guy and appreciated the honesty and asked if this junior guy would some day want to lead a team of developers?
The junior guy said "Yes." promptly.
The director then asked if the stakeholders would be eager to know how long the team would be able to deliver the software.
The junior guy said "Yes." again.
The director asked - "So, how would you learn to estimate?"
"By experience" was the reply.
The director asked - "How would you gain that experience?"
This hit the junior guy in the face. Both he and the director knew what he was thinking.
The answer was - "By estimating regularly".

The junior guy had learnt early in his career a very important lesson which later helped him give estimates better that Dilbert.

Websites not opening on Ubuntu

2012-09-10T22:47:00.000-07:00

Symptoms:
Websites won't load but services like skype seems to work.

It has happened to me twice -
I had shutdown the system without properly closing juniper connection and this started happening.

Solution:

1. Take a backup of /etc/resolv.conf
2. Now clear all the contents of /etc/resolv.conf
3. Restart your networking services (I disabled the network and enabled it).

Things should work...

How to mount windows share on Ubuntu Server

2012-09-05T02:52:00.000-07:00

sudo mkdir -p /mnt/ntserver

sudo mount -t cifs "//server-name-or-ip/share/path" -o user=myuser,password=mypass /mnt/ntserver

Flash messages on Express js 3

2012-08-11T10:19:00.000-07:00

Trying Express js 3 and received an exception on the following?

req.flash()

TypeError: Object # has no method 'flash'

Apparently Express js has dropped support for flash messages in their latest version - 3.

Here's the recommended middle-ware plugin to resolve the problem:

https://github.com/tehlulz/flashify

Gotchas:

Be sure to use
app.use(flashify);
before
app.use(app.router);
for it to work.

Enjoy!

Undo a commit on Github

2012-07-11T10:58:00.000-07:00

I had pushed a commit onto master. It made sense at that time, but I soon realized it wasn't a wise decision.

Wanted to revert it but had to look out for a while to figure out how to.
Here's the procedure:

git reset --hard HEAD^

This would undo last commit.
Keep executing this command till you get to the desired top commit. Then execute the following to finally commit to Github:

git push origin +master

This pushes the changes forcefully.

Using Rhohub to build Rhomobile applications targeting iOS (for Windows/Linux users and dummies)

2012-04-30T21:00:00.000-07:00

1. Generate your developer certificate and provisioning profile

All iOS applications must be signed by a valid certificate, which you should get from Apple, before they can be run on an Apple device. For privacy, the signing certificate you upload to RhoHub is used only once and thrown away.

Windows or Linux

Install OpenSSL if you don't have it (on Windows, OpenSSL is included in Git Bash).
Follow the generating a certificate signing request instructions on the iOS developer portal.
Execute the following commands to generate your certificate signing request, filling in your email address used in the development portal:

openssl genrsa -out mykey.key 2048
openssl req -new -key mykey.key -out CertificateSigningRequest.certSigningRequest -subj '/emailAddress=yourAddress@example.com, CN=John Doe, C=US'

Upload the resulting certSigningRequest file to the developer portal.
After the certificate has been generated, download the .cer file and use the following commands to convert it to the .p12 format. You will be prompted for an export password. This is a new password for this file and cannot be blank.
```
openssl x509 -in developer_identity.cer -inform DER -out developer_identity.pem -outform PEM
openssl pkcs12 -export -inkey mykey.key -in developer_identity.pem -out iphone_dev.p12
```
Create a provisioning profile and associate your developer certificate with it and download it. Lets call it your_app.mobileprovision

2. Configure build.yml

Follow the instructions given at http://docs.rhomobile.com/rhodes/build#building-a-rhodes-application-for-iphoneipad

provisionprofile: E5931D39-CA68-48E4-A3AF-BB538E1C8CE6

Here's how I found the UID associated with provision profile:

1. Use any binary file viewer. Eg. binary viewer for windows, ghex for linux to open your_app.mobileprovision.

2. Locate the tag UUID. It would look something like the following

<string>5349A91C-FABC-ABCD-BB5A-8D36B186XXXX</string>
This string is what goes into your provision profile.

codesignidentity: "iPhone Developer: John Smith (MF99RW67WY)"

Open the certificate - iphone_dev.p12. It has this information in the exact same format.

BundleIdentifier: com.johnsmithcompany.jsapp

Notice the app id in your provisioning portal. Should look like some random hex followed by com.yourcompany.app.blah. eg. G2GXEVYDX5.com.johnsmithcompany.jsapp

So, if you just copy everything other than the <hex><dot>, it should give your your bundle identifier.

3. Push to Rhohub

4. Build

Needless to say, select iOS in target device.
Select iphone_dev.p12 file to upload as the certificate, and enter the certificate password that you used while making the p12.
Select provisioning profile and give the same bundle identifier that you gave in your build.yml

Now press "build" and relax...

Deploying a Rails Application on Red Hat Server using RVM, NGINX, Passenger, Oracle, SVN

2012-04-21T01:37:00.000-07:00

Using Red Hat? Oracle? SVN (When there's git!)?
Its a pain, here's the answer.

#Add EPEL to yum
rpm -ivh http://dl.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm
yum update

# Create the rvm group and add any users who will be using rvm to the group
sudo su -
groupadd rvm

# Start by adding the root user (required to install RVM)
usermod -a -G rvm root

# Then add any other users who need access to to the rvm group and logout of the superuser account
logout

#Now install RVM
curl -L get.rvm.io | bash -s stable

#Load RVM:
$ source ~/.rvm/scripts/'rvm'

#install git
rpm -Uvh http://repo.webtatic.com/yum/centos/5/latest.rpm
sudo yum install --enablerepo=webtatic git

#install ruby - takes some time...
rvm install 1.9.3
rvm use 1.9.3 --default

#install bundler
gem install bundler

gem install rails -v 3.1.0

#fetch the application. Goto your deployment directory and do
svn checkout

#Edit the rails configuration files:
config/environments/production.rb
config/database.yml

#install Oracle
#Get the instant client packages from Oracle and do the following
sudo rpm -i oracle-instantclient11.2-basic-11.2.0.3.0-1.x86_64.rpm
sudo rpm -i oracle-instantclient11.2-devel-11.2.0.3.0-1.x86_64.rpm
LD_LIBRARY_PATH=/usr/lib/oracle/11.2/client64/lib/
export LD_LIBRARY_PATH

#install the gems
bundle install

#Precompile assets
rake assets:precompile RAILS_ENV=production

#create the service_log directory
mkdir log/service_log

#now we need to get some permissions straight
chmod -R 777 tmp
chmod -R 777 log/service_log

#install passenger
gem install passenger

#install nginx. Accept all the defaults
rvmsudo passenger-install-nginx-module

#Here's the nginx conf file /opt/nginx/conf/nginx.conf
#Here are some helpful locations
# passenger_root /usr/local/rvm/gems/ruby-1.9.3-p125/gems/passenger-3.0.12;
# passenger_ruby /usr/local/rvm/wrappers/ruby-1.9.3-p125/ruby;

#Copy the config file
sudo cp /opt/nginx/conf/nginx.conf /opt/nginx/conf/nginx.conf.bak
rm /opt/nginx/conf/nginx.conf
cp installation_dump/nginx.conf /opt/nginx/conf/nginx.conf

#update the configurations (eg. the rails app public path, port number, server name etc. and stuff similar to what you might be doing with java web servers)
nano /opt/nginx/conf/nginx.conf

#Copy the nginx start/stop helper script
sudo cp installation_dump/nginx /etc/init.d/

#finally
sudo /etc/init.d/nginx start

#Troubleshoot - if you see nothing after start you can debug using
sudo /etc/init.d/nginx configtest

Google+ style circles Drag Drop using Rails

2011-08-05T12:13:00.000-07:00

A working example for Google+ style circles drag drop using Rails 2.3.

The only challenge was how to make the Draggable elements drag across a scrollable div.
It was solved by using the library at http://scripteka.com/script/dragdropextra