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

Constant Summary collapse

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

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 15

def initialize directory
  @directory               = directory
  @data_files              = []
  @index = []
  @iterator = 1

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

  index_path = File.join(@directory, 'index')

  if File.exists?(index_path) && File.size(index_path) > 0
    @index_file = File.open(index_path, 'r+')

    @index_file.each_line do |line|
      @index << parse_headers(line.strip, true)
      @last_id = @index.last[:id]
    end
    @index_file.seek(0, IO::SEEK_END)
  else
    @index_file = File.open(index_path, 'a')
    @last_id = 0
  end
  @index_file.sync = true

end

Class Method Details

.valid_channel_name?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/conveyor/base_channel.rb', line 114

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

Instance Method Details

#bucket_file(i) {|| ... } ⇒ Object

Yields:

  • () 


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# File 'lib/conveyor/base_channel.rb', line 55

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
  end
  yield @data_files[i]
end

#commit(data, time = nil) ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 63

def commit data, time = nil
  Thread.exclusive do
    i = @last_id + 1
    t = time || Time.now
    l = data.length
    h = Digest::MD5.hexdigest(data)
    b = pick_bucket(i)
    header, o = nil
    bucket_file(b) do |f|
      f.seek(0, IO::SEEK_END)
      o = f.pos
      header = "#{i} #{t.xmlschema} #{o} #{l} #{h}"
      f.write("#{header}\n" + data + "\n")
    end

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

#get(id) ⇒ Object 



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# File 'lib/conveyor/base_channel.rb', line 85

def get id
  return nil unless id <= @last_id
  i = @index.find{|e| e[:id] == id}
  header, content = nil
  Thread.exclusive do
    bucket_file(i[:file]) do |f|
      f.seek i[:offset]
      header  = f.readline.strip
      content = f.read(i[:length])
    end
  end
  [parse_headers(header), content]
end

#inspect ⇒ Object 



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

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 99

def parse_headers str, index_file=false
  pattern =  '\A(\d+) (\d{4}\-\d{2}\-\d{2}T\d{2}\:\d{2}\:\d{2}[+\-]\d{2}\:\d{2}) (\d+) (\d+) ([a-f0-9]+)'
  pattern += ' (\d+)' if index_file
  pattern += '\Z'
  m = str.match(Regexp.new(pattern))
  {
    :id => m.captures[0].to_i,
    :time => m.captures[1],
    :offset => m.captures[2].to_i,
    :length => m.captures[3].to_i,
    :hash => m.captures[4], 
    :file => (index_file ? m.captures[5].to_i : nil)
  }.reject {|k,v| v == nil}
end

#pick_bucket(i) ⇒ Object 



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

def pick_bucket i
  (i / BUCKET_SIZE).to_i
end