Capistrano steps

1.rb

# Installation

gem install capistrano

# Setting up capistrano
# Go to your application directory in the terminal and run capify .

capify .

cap deploy:setup

# This is the first command you would want to run. 
# What this is going to do is that, it will setup all of the configurations in place for you.

# Next up :
cap deploy:check

# This command would check all the configurations and generate any errors on the configurations
# point of view. You can then fix these issues regarding your VM before taking the final step.

cap deploy

# Finally, this would deploy.

2.rb

# What happens when you cap deploy ?

cap deploy

# assume in your deploy.rb, you have

set :deploy_to, location

if folder is available at "deploy_to" location/shared/cached_copy
  cd location/shared/cached_copy && perform a git fetch -q 
  # What does git fetch "-q" do ? Well, in simple terms, it would perform the fetch operation
  # silently. It would basically silence / block / not perform any other git operations on that repo 
  # until this operation is completed.
                  
    && git fetch --tags -q && git reset -q --hard 
    # git reset will reset your branch to the last commit and remove all the uncommitted changes you 
    # have performed in that particular branch quietly with "-q".

      && git clean -q -d -f -x
      # git clean would remove all the untracked files from your respective branch.
      # -d : remove directories as well.
      # -f : force remove
      # -x : Don't use the standard .gitgnore
else
  && git clone -q the repo && cd into the new clone && git checkout -b deploy "Some_code_in_hex"
end

# copying the cached version to Users/kaushik/dev/quadmint/releases/Some_code_in_hex_here

cp -RPp "path/to/cached_copy" "path/to/releases/Some_code_in_hex" && (echo "Some_another_code_in_hex" > /releases/Some_code_in_hex/REVISION)

# -R ::
    # Copy the folder and subtree (recursive).  
    # If source_file designates a directory, cp copies the directory and
    # the entire subtree connected at that point.  If the source_file
    # ends in a /, the contents of the directory are copied rather than
    # the directory itself.  This option also causes symbolic links to be
    # copied, rather than indirected through, and for cp to create special
    # files rather than copying them as normal files.  Created
    # directories have the same mode as the corresponding source directory,
    # unmodified by the process' umask.

# -P ::
    # No symbolic links are followed

# -p ::
    # Cause cp to preserve the following attributes of each source file
    # in the copy: modification time, access time, file flags, file mode,
    # user ID, and group ID, as allowed by permissions.

# This callback would be called upon after this ::
deploy:finalize_update

rm -rf "releases/Some_code_in_hex/log" "releases/Some_code_in_hex/public/system" "releases/Some_code_in_hex/tmp/pids" 
    
    && mkdir -p "/releases/Some_code_in_hex/public" "/releases/Some_code_in_hex/tmp" "/shared/log"

    && ln -s "/shared/log" "/releases/Some_code_in_hex/log" "/shared/system" "releases/Some_code_in_hex/public/system" "shared/pids" "releases/Some_code_in_hex/tmp/pids"

# ln creates a link and -s creates a symbloic link.

find "releases/Some_code_in_hex/public/images" "releases/Some_code_in_hex/public/stylesheets" "releases/Some_code_in_hex/public/javascripts"

# find the assets.

rm -f "/current/" && ln -s "releases/Some_code_in_hex/" "/current"

# make the latest code as the current code.