Class: Ec2Hosts::Updater

Inherits:
Object
  • Object
show all
Defined in:
lib/ec2_hosts/updater.rb

Overview

Updater implements a simple state machine which is used to update content between zero or more blocks of content which start and end with pre-defined “marker” lines.

Defined Under Namespace

Modules: Marker

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Updater

Returns a new instance of Updater.



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# File 'lib/ec2_hosts/updater.rb', line 15

def initialize(options = {})
  @options = options
end

Instance Attribute Details

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/ec2_hosts/updater.rb', line 13

def options
  @options
end

Instance Method Details

#clear ⇒ Object 



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# File 'lib/ec2_hosts/updater.rb', line 68

def clear
  old_hosts = File.read(options[:file])
  new_content = old_hosts.dup

  markers = old_hosts.each_line.map do |line|
    regex = "\# (START|END) EC2 HOSTS - (.+) \#"
    if m = line.match(/^#{regex}$/)
      m[2]
    end
  end.compact.uniq

  markers.each do |project|
    new_content = delete_vpc_hosts(new_content)
  end
  new_content.gsub!(/\s+$/, "\n")

  if options[:dry_run]
    puts new_content
  elsif new_content != old_hosts
    # backup old host file
    File.open(options[:file], 'w') { |f| f << old_hosts }
    # write new content
    File.open(options[:file], 'w') { |f| f << new_content }
  end
end

#update(new_hosts) ⇒ Object 



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# File 'lib/ec2_hosts/updater.rb', line 19

def update(new_hosts)
  old_hosts = File.read(options[:file])

  if old_hosts.include?(start_marker) && old_hosts.include?(end_marker)
    # valid markers exists
    if options[:delete]
      new_content = delete_vpc_hosts(old_hosts)
    else
      new_content = gen_new_hosts(old_hosts, new_hosts)
    end

    # remove zero or more white space characters at end of file with
    # a single new-line
    new_content.gsub!(/\s+$/, "\n")

    if options[:dry_run]
      puts new_content
    elsif new_content != old_hosts
      # backup old host file
      File.open(options[:backup], 'w') { |f| f << old_hosts }
      # write new content
      File.open(options[:file], 'w') { |f| f << new_content }
    end
  elsif old_hosts.include?(start_marker) || old_hosts.include?(end_marker)
    raise UpdaterError.new("Invalid marker present in existing hosts content")
  else
    # marker doesn't exist
    if options[:delete]
      new_content = old_hosts
    else
      new_content = [old_hosts, start_marker, new_hosts, end_marker].join("\n")
    end
    # remove one or more white space characters at end of file with
    # a single new-line
    new_content.gsub!(/\s+$/, "\n")

    if options[:dry_run]
      puts new_content
    elsif new_content != old_hosts
      # backup old host file
      File.open(options[:backup], 'w') { |f| f << old_hosts }
      # write new content
      File.open(options[:file], 'w') { |f| f << new_content }
    end
  end

  true
end