Class: Baha::Dockerfile

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

Constant Summary collapse

LOG = 
Baha::Log.for_name("Dockerfile")

Class Method Summary collapse

Class Method Details

.append_attr(image, key, value) ⇒ Object 



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# File 'lib/baha/dockerfile.rb', line 78

def append_attr(image,key,value)
  image[key] = [] unless image.has_key?(key)
  case value
  when Array
    image[key].concat(value)
  else
    image[key].push(value)
  end
end

.as_array(args) ⇒ Object 



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# File 'lib/baha/dockerfile.rb', line 62

def as_array(args)
  begin
    return JSON.parse(args)
  rescue
    return CSV.parse_line(args,{:col_sep => " ", })
  end
end

.as_cmd(cmd) ⇒ Object 



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# File 'lib/baha/dockerfile.rb', line 70

def as_cmd(cmd)
  begin
    return JSON.parse(cmd)
  rescue
    cmd
  end
end

.parse(file) ⇒ Object 



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# File 'lib/baha/dockerfile.rb', line 22

def parse(file)
  LOG.info { "Parsing Dockerfile: #{file}" }
  linenum = 0
  image = {
    'run' => [],
    'pre_build' => [],
    'config' => {}
  }
  multiline = []
  f = File.open(file, "r")
  begin
    f.each_line do |rawline|
      linenum = linenum + 1
      line = rawline.chomp.gsub(/^\s*/,'')
      # Skip empty lines
      next if line.empty?
      # Skip comments
      next if line.match(/^#/)
      
      # Buffer multi-lines
      if line.match(/\\$/)
        multiline << line.chop
        next
      end
      multiline << line


      line_to_parse = multiline.join("\n")
      LOG.debug { "Parsing #{linenum}: #{line_to_parse}" }
      unless parse_line(image,line_to_parse)
        raise DockerfileParseError.new(file,linenum, line_to_parse)
      end
      multiline = []
    end
  ensure
    f.close
  end
  image
end

.parse_line(image, line) ⇒ Object

Parse a line and configure the image



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# File 'lib/baha/dockerfile.rb', line 119

def parse_line(image,line)
  cmd, args =  line.split(/\s+/,2)
  cmd = cmd.downcase.to_sym
  case cmd
  when :from
    image['parent'] = args
  when :maintainer
    image['maintainer'] = args
  when :expose
    append_attr(image['config'],'exposedports',resolve_env(image,args))
  when :volume
    append_attr(image['config'],'volumes',as_array(resolve_env(image,args)))
  when :entrypoint
    image['config']['entrypoint'] = as_cmd(args)
  when :cmd
    image['config']['cmd'] = as_cmd(args)
  when :run
    image['run'] << as_cmd(args)
  when :user
    image['config']['user'] = resolve_env(image,args)
  when :workdir
    set_workdir(image,args)
  when :env
    set_env(image,resolve_env(image,args))
  else
    return false
  end
  true
end

.resolve_env(image, value) ⇒ Object

Resolve environment variables in the string



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# File 'lib/baha/dockerfile.rb', line 89

def resolve_env(image,value)
  if image['config'].has_key?('env')
    env = image['config']['env']
    env.keys.reduce(value) do |v,k|
      r = Regexp.new("(?<!\\\\)[$](?:\\{#{k}\\}|#{k})")
      v.gsub(r,env[k])
    end
  else
    value
  end
end

.set_env(image, value) ⇒ Object 



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# File 'lib/baha/dockerfile.rb', line 112

def set_env(image,value)
  k,v = value.split(/\s+/,2)
  image['config']['env'] ||= {}
  image['config']['env'][k] = v
end

.set_workdir(image, value) ⇒ Object

Sets the workdir on the image config



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# File 'lib/baha/dockerfile.rb', line 102

def set_workdir(image,value)
  wd = image['config']['workingdir']
  if wd
    wd = (Pathname.new(wd) + value).to_s
  else
    wd = value
  end
  image['config']['workingdir'] = resolve_env(image,wd)
end