Class: Dockerfile2bash

Inherits:
Object
  • Object
show all
Defined in:
lib/dockerfile2bash.rb

Constant Summary collapse

VERSION = 
'0.1.4'
FIELDS = 
%w(from user run add copy arg env expose cmd onbuild)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dockerfile) ⇒ Dockerfile2bash

Returns a new instance of Dockerfile2bash.



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# File 'lib/dockerfile2bash.rb', line 9

def initialize(dockerfile)
  @dockerfile = dockerfile
  @content = get_content
  @commands = []
end

Instance Attribute Details

#commands ⇒ Object (readonly)

Returns the value of attribute commands.



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# File 'lib/dockerfile2bash.rb', line 6

def commands
  @commands
end

Instance Method Details

#generate_bash ⇒ Object 



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# File 'lib/dockerfile2bash.rb', line 66

def generate_bash()
  return unless @commands
  bash = "#!/usr/bin/env bash \n\n# The script is generated from a Dockerfile via Dockerfile2bash(v#{VERSION})\n# By B1nj0y <[email protected]>\n\n"
  @commands.each do |cmd|
    case cmd.keys[0]
    when "from"
      bash << "# The original Dockerfile is from a base image: <#{cmd["from"]}> \n\n"
    when "run"
      bash << cmd["run"] << "\n"
    when "arg"
      bash << cmd["arg"].join("=") << "\n"
    when "env"
      env_str = "export " << cmd["env"]
      bash << env_str << "\n"
      bash << "echo \'#{env_str}\' >> ~/.bashrc" << "\n"
    end
  end
  bash
end

#get_content ⇒ Object 



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# File 'lib/dockerfile2bash.rb', line 86

def get_content
  if @dockerfile =~ /^https:\/\/raw\.githubusercontent\.com\/.+$/
    content = RestClient.get(@dockerfile)
  elsif @dockerfile =~ /^https:\/\/github\.com\/(.+)$/
    # convert to its corresponding raw url
    url = "https://raw.githubusercontent.com/#{$1.sub('/blob/', '/')}"
    content = RestClient.get(url)
  else
    # local file
    content = File.read(@dockerfile)
  end
  content
end

#parse ⇒ Object 



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# File 'lib/dockerfile2bash.rb', line 15

def parse
  return unless @content || @content.empty?
  @content.gsub!("\\\n", "")
  lines = @content.split(/\r?\n+/) || []

  lines.each do |line|
    # ignore blank and comment lines
    next if /^\s*$/ =~ line
    next if /^\s*#/ =~ line
    segments = line.split(" ", 2)
    next if segments.length < 2 or !FIELDS.include?(segments[0].downcase)

    case segments[0].downcase!
    when "from", "user", "run", "expose", "copy", "add"
      @commands << { segments[0] => segments[1] }
    when "cmd"
      @commands << { "cmd" => (JSON.parse(segments[1]) || []).join(" ") }
    when "arg"
      args = segments[1].split("=", 2)
      if args.length == 2
        @commands << { "arg" => args }
      end
    when "env"
      if segments[1] =~ /^[a-zA-Z_].[a-zA-Z0-9_]+?=("|')[^"']*?\1$/
        @commands << { "env" => segments[1] }
        next
      end

      envs = segments[1].split
      pattern = %r/^[a-zA-Z_].[a-zA-Z0-9_]+?=.+$/
      case envs.length
      when 1
        @commands << { "env" => segments[1] }
      when 2
        if envs.all? { |e| e =~ pattern }
          @commands << { "env" => segments[1] }
        else
          @commands << { "env" => envs.join("=") }
        end
      else
        if envs.all? { |e| e =~ pattern }
          @commands << { "env" => segments[1] }
        else
          @commands << { "env" => [envs[0], "\"#{envs[1..-1].join(" ")}\""].join("=") }
        end
      end
    end
  end
  @commands
end