Class: Conveyor::BaseChannel

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

Overview

BaseChannel

Base implementation for channels. Not useful to instantiate directly.

Direct Known Subclasses

Channel

Defined Under Namespace

Modules: Flags

Constant Summary collapse

NAME_PATTERN = 
%r{\A[a-zA-Z\-0-9\_]+\Z}
BUCKET_SIZE = 
100_000
FORMAT_VERSION = 
1

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(directory) ⇒ BaseChannel

Returns a new instance of BaseChannel.



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# File 'lib/conveyor/base_channel.rb', line 22

def initialize directory
  @directory    = directory
  @data_files   = []
  @file_mutexes = []
  @index        = []
  @iterator     = 1
  @id_lock      = Mutex.new

  if File.exists?(@directory)
    if !File.directory?(@directory)
      raise "#{@directory} is not a directory"
    end
    load_channel
  else
    Dir.mkdir(@directory)
    setup_channel
  end

  @index_file.sync    = true
end

Class Method Details

.parse_headers(str, index_file = false) ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 130

def self.parse_headers str, index_file=false
  pattern =  '\A([a-z\d]+) ([a-z\d]+) ([a-z\d]+) ([a-z\d]+) ([a-f0-9]+) ([a-z\d]+)'
  pattern += ' (\d+)' if index_file
  pattern += '\Z'
  m = str.match(Regexp.new(pattern))
  {
    :id     => m.captures[0].to_i(36),
    :time   => m.captures[1].to_i(36),
    :offset => m.captures[2].to_i(36),
    :length => m.captures[3].to_i(36),
    :hash   => m.captures[4],
    :flags  => m.captures[5].to_i(36),
    :file   => (index_file ? m.captures[6].to_i(36) : nil)
  }
end

.valid_channel_name?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/conveyor/base_channel.rb', line 150

def self.valid_channel_name? name
  !!name.match(NAME_PATTERN)
end

Instance Method Details

#bucket_file(i) ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 51

def bucket_file i
  unless @data_files[i]
    @data_files[i] = File.open(File.join(@directory, i.to_s), 'a+')
    @data_files[i].sync = true
    @file_mutexes[i] = Mutex.new
  end
  @file_mutexes[i].synchronize do
    yield @data_files[i]
  end
end

#commit(data, time = nil) ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 68

def commit data, time = nil
  l = nil
  gzip = data.length >= 256
  if gzip
    compressed_data = StringIO.new
    g = Zlib::GzipWriter.new(compressed_data)
    g << data
    g.finish
    compressed_data.rewind
    compressed_data = compressed_data.read
    l = compressed_data.length
  else
    l = data.length
  end

  h = Digest::MD5.hexdigest(data)

  id_lock do
    i = @last_id + 1
    t = time || Time.now
    b = pick_bucket(i)
    flags = 0
    flags = flags | Flags::GZIP if gzip
    header, o = nil
    bucket_file(b) do |f|
      f.seek(0, IO::SEEK_END)
      o = f.pos
      header = "#{i.to_s(36)} #{t.to_i.to_s(36)} #{o.to_s(36)} #{l.to_s(36)} #{h} #{flags.to_s(36)}"
      f.write("#{header}\n")
      f.write((gzip ? compressed_data : data))
      f.write("\n")
    end

    @last_id = i
    @index_file.write "#{header} #{b.to_s(36)}\n"
    @index << {:id => i, :time => t, :offset => o, :length => l, :hash => h, :file => b}
    i
  end
end

#delete! ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 154

def delete!
  FileUtils.rm_r(@directory)
  @index = []
  @data_files =[]
  @last_id = 0
end

#get(id, stream = false) ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 108

def get id, stream = false
  return nil unless id <= @last_id && id > 0
  i = @index[id-1]
  headers, content, compressed_content, g = nil
  bucket_file(i[:file]) do |f|
    f.seek i[:offset]
    headers  = parse_headers(f.readline.strip)
    compressed_content = f.read(i[:length])
  end
  io = StringIO.new(compressed_content)
  if (headers[:flags] & Flags::GZIP) != 0
    g  = Zlib::GzipReader.new(io)
  else
    g = io
  end
  if stream
    [headers, g]
  else
    [headers, g.read]
  end
end

#id_lock ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 62

def id_lock
  @id_lock.synchronize do
    yield
  end
end

#inspect ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 43

def inspect
  "<#{self.class} dir:'#{@directory.to_s}' last_id:#{@last_id} iterator:#{@iterator}>"
end

#parse_headers(str, index_file = false) ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 146

def parse_headers str, index_file=false
  self.class.parse_headers str, index_file
end

#pick_bucket(i) ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 47

def pick_bucket i
  (i / BUCKET_SIZE).to_i
end