Thursday, November 27, 2014

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

Solution : Install : MySQL Server DMG Installer for Mac OS 10.9.4

An error occurred while installing libv8 (3.11.8.13), and Bundler cannot continue

 I was getting that error on Mac 10.9.4. I had to update the gems :

gem 'libv8', '3.16.14.7'
gem 'therubyracer', '~> 0.12.0'

to fix this problem.

Reference : An error occurred while installing libv8 – Mavericks

Monday, November 24, 2014

Deploying a Rails App on Google App Engine

Deploying a Rails Webapp on GAE should be a piece of cake right? Due to lack of good documentation, it is not that easy. I had to dig around to find the versions of the software installed for Ruby Stack One-Click Deploy.

Here is some useful information to access installed software components.
Apache web server:  

Configuration directory: /etc/apache2
Default website directory: /var/www
Command to start Apache web server: sudo service apache2 start
Command to stop Apache web server: sudo service apache2 stop

Passenger:

Help command: passenger --help
Install directory: /usr/local/rvm/gems/ruby-2.1.1/gems/passenger-4.0.48

MySQL:

Command to access MySQL: mysql -u root -p
Command to start MySQL service: sudo service mysql start
Command to stop MySQL service: sudo service mysql stop

RVM, Ruby and Rails:

RVM Help command: rvm
Rails help command: rails -h
RVM install directory: /usr/local/rvm
Ruby install directory: /usr/local/rvm/src/ruby-2.1.1
Rails install directory: /usr/local/rvm/gems/ruby-2.1.1/gems/rails-4.1.4

Git:
Help command: git --help

Saturday, November 22, 2014

bin/rails:6: warning: already initialized constant APP_PATH

I was getting this error in Rails 4.2 beta when I started the rails server. Solution: run : rake rails:update:bin from rails project directory.

git Illegal instruction: 4 mac 10.7.5

Download the git for Mac 10.7.5  and restart your terminal.

Tuesday, November 18, 2014

Evolution of Rails from 1.0, 2.0 and 4.0

Rails 1.0



Rails 2.0



Rails 4.0



Friday, November 14, 2014

Stripe API Capybara Test Failures

I was getting Stripe::InvalidRequestError: You must supply either a card or a customer id error. To fix this, make sure js is true in your integration test like this:

feature 'Guest Checkout' do
  scenario 'Complete purchase of one product', js: true do
    visit products_show_path
    click_link 'Buy Now'
   
    fill_in "Card Number", with: '4242424242424242'  
    page.select '10', from: "card_month"
    page.select '2029', from: 'card_year'
    click_button 'Buy Now'
   
    expect(page).to have_content('Receipt')
  end
end

Thursday, November 13, 2014

Base Ball Player Statistics

Overview:  For this scenario, we have been asked to write an application that will be used to provide information about baseball player statistics.  Approach this problem as if it is an application going to production.  We don't expect it to be perfect (no production code is), but we also don't want you to hack together a throw-away script.  This should be representative of something that you would be comfortable releasing to a production environment.  Also, spend whatever amount of time you think is reasonable.  If you don't get all the requirements completed, that's ok.  Just do the best you can with the time that you have available.  You may use whatever gems, frameworks and tools that you think are appropriate, just provide any special setup instructions when you submit your solution.

Assumptions:  All requests currently are based on data in the hitting file.  Future requests of the system will require data from a pitching file as well.  Consider this in the design.

Requirements: When the application is run, use the provided data and calculate the following results and write them to STDOUT.

1) Most improved batting average( hits / at-bats) from 2009 to 2010.  Only include players with at least 200 at-bats.
2) Slugging percentage for all players on the Oakland A's (teamID = OAK) in 2007. 
3) Who was the AL and NL triple crown winner for 2011 and 2012.  If no one won the crown, output "(No winner)"

Formulas:
Batting average = hits / at-bats
Slugging percentage = ((Hits – doubles – triples – home runs) + (2 * doubles) + (3 * triples) + (4 * home runs)) / at-bats
Triple crown winner – The player that had the highest batting average AND the most home runs AND the most RBI in their league. It's unusual for someone to win this, but there was a winner in 2012. “Officially” the batting title (highest league batting average) is based on a minimum of 502 plate appearances. The provided dataset does not include plate appearances. It also does not include walks so plate appearances cannot be calculated. Instead, use a constraint of a minimum of 400 at-bats to determine those eligible for the league batting title.


Data:  All the necessary data is available in the two csv files attached:

Batting-07-12.csv – Contains all the batting statistics from 2007-2012.  
Column header key:
AB – at-bats
H – hits
2B – doubles
3B – triples
HR – home runs
RBI – runs batted in

Master-small.csv – Contains the demographic data for all baseball players in history through 2012.


Please note: We are looking for you to demonstrate you knowledge related to common software practices to include reusability, portability, and encapsulation – to name a few. Work submitted should be in project form and implemented as you were implementing any production solution.


Tuesday, November 11, 2014

How to share files between Virtual Box Ubuntu with Mac OS host computer

1. Create a folder in your Mac home directory, let's say ubuntu-sf.
2. Install guest additions. Click Devices -> Guest Additions and run the installer.
3. Reboot VM
4. Select the Ubuntu image on VM, go to Settings -> Shared Folders
5. Browse to the folder on your Mac you want to share (ubuntu-sf). Name the shared folder (ubuntu-sf)
6. On Ubuntu terminal, run : sudo adduser your-username vboxsf
7. On Ubuntu terminal run: sudo mount -t vboxsf ubuntu-sf /home/bparanj/ubuntu-sf
   Here ubuntu-sf is the name of the shared folder we created in step 5. /home/bparanj/ubuntu-sf is the folder in the
   Ubuntu.


References

How to share files between Virtual Box Ubuntu and host computer
How to automatically mount a folder and change ownership from root in virtualbox


some of the partitions you created are too small ubuntu 12.04 LTS Precise Pangolin

I was getting this error during installation of Ubuntu on Virtual Box. Solution: Increase the hard disk size from default 8GB to something higher. It worked for 45GB.