Module: Kage::Connection

Defined in:
lib/kage/connection.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#master_backend ⇒ Object

Returns the value of attribute master_backend.



5
6
7
 
# File 'lib/kage/connection.rb', line 5

def master_backend
  @master_backend
end

#session_id ⇒ Object

Returns the value of attribute session_id.



5
6
7
 
# File 'lib/kage/connection.rb', line 5

def session_id
  @session_id
end

Instance Method Details

#all_servers_finished? ⇒ Boolean

Returns:

  • (Boolean) 


31
32
33
 
# File 'lib/kage/connection.rb', line 31

def all_servers_finished?
  @servers.values.compact.size.zero?
end

#build_headers(parser, headers) ⇒ Object 



45
46
47
48
49
 
# File 'lib/kage/connection.rb', line 45

def build_headers(parser, headers)
  "#{parser.http_method} #{parser.request_url} HTTP/#{parser.http_version.join(".")}\r\n" +
  headers.map{|k, v| "#{k}: #{v}\r\n" }.join('') +
  "\r\n"
end

#callback(cb, *args) ⇒ Object 



35
36
37
38
39
40
41
42
43
 
# File 'lib/kage/connection.rb', line 35

def callback(cb, *args)
  if @callbacks[cb]
    instance_exec *args, &@callbacks[cb]
  elsif block_given?
    yield
  end
rescue Exception => e
  info "#{e} - #{e.backtrace}"
end

#cleanup! ⇒ Object 



27
28
29
 
# File 'lib/kage/connection.rb', line 27

def cleanup!
  @parser.reset!
end

#close_connection(*args) ⇒ Object

eventmachine.rubyforge.org/EventMachine/Connection.html#unbind-instance_method



8
9
10
11
 
# File 'lib/kage/connection.rb', line 8

def close_connection(*args)
  @server_side_close = true
  super
end

#connect_backends!(req, headers, backends) ⇒ Object 



51
52
53
54
55
56
57
58
59
60
 
# File 'lib/kage/connection.rb', line 51

def connect_backends!(req, headers, backends)
  @backends = select_backends(req, headers).select {|b| backends[b]}
  @backends.unshift master_backend unless @backends.include? master_backend
  info "Backends for #{req[:method]} #{req[:url]} -> #{@backends}"

  @backends.each do |name|
    s = server name, backends[name]
    s.comm_inactivity_timeout = 10
  end
end

#handle(server) ⇒ Object 



66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
 
# File 'lib/kage/connection.rb', line 66

def handle(server)
  self.comm_inactivity_timeout = server.client_timeout
  self.master_backend = server.master

  @session_id = "%016x" % Random.rand(2**64)
  info "New connection"

  @callbacks = server.callbacks

  @responses = {}
  @request = {}
  @requests = []

  @state = :request

  @parser = HTTP::Parser.new
  @parser.on_message_begin = proc do
    @start_time ||= Time.now
    @state = :request
  end

  @parser.on_headers_complete = proc do |headers|
    @request = {
      :method => @parser.http_method,
      :path => @parser.request_path,
      :url => @parser.request_url,
      :headers => headers
    }
    @requests.push @request
    info "#{@request[:method]} #{@request[:url]}"

    # decide backends on the first request
    unless @backends
      connect_backends!(@request, headers, server.backends)
    end

    if @backends.size > 1
      info "Multiple backends for this session: Force close connection (disable keep-alives)"
      headers['Connection'] = 'close'
    end

    @servers.keys.each do |backend|
      callback :on_munge_headers, backend, headers
      relay_to_servers [build_headers(@parser, headers), [backend]]
    end
  end

  @parser.on_body = proc do |chunk|
    relay_to_servers chunk
  end

  @parser.on_message_complete = proc do
    @state = :response
  end

  on_data do |data|
    begin
      @parser << data
    rescue HTTP::Parser::Error
      info "HTTP parser error: Bad Request"
      EM.next_tick { close_connection_after_writing }
    end
    nil
  end

  # modify / process response stream
  on_response do |backend, resp|
    @responses[backend] ||= {}
    @responses[backend][:elapsed] = Time.now.to_f - @start_time.to_f
    @responses[backend][:data] ||= ''
    @responses[backend][:data] += resp

    resp if backend == master_backend
  end

  # termination logic
  on_finish do |backend|
    # terminate connection (in duplex mode, you can terminate when prod is done)
    if all_servers_finished?
      if @backends.all? {|b| @responses[b]}
        callback :on_backends_finished, @backends, @requests, @responses if @backends.size > 1
      else
        info "Server(s) disconnected before response returned: #{@backends.reject {|b| @responses[b]}}"
      end
      cleanup!
    end

    if backend == master_backend
      info "Master backend closed connection. Closing downstream"
      :close
    end
  end
rescue Exception => e
  info "#{e} - #{e.backtrace}"
end

#info(msg) ⇒ Object 



162
163
164
 
# File 'lib/kage/connection.rb', line 162

def info(msg)
  puts "#{Time.now.strftime('%H:%M:%S')} [#{@session_id}] #{msg}"
end

#select_backends(request, headers) ⇒ Object 



62
63
64
 
# File 'lib/kage/connection.rb', line 62

def select_backends(request, headers)
  callback(:on_select_backends, request, headers) { [master_backend] }
end

#unbind ⇒ Object 



13
14
15
16
17
18
19
20
21
22
23
24
25
 
# File 'lib/kage/connection.rb', line 13

def unbind
  if !@server_side_close
    if @state == :request
      info "Client disconnected in the request phase"
      super
    elsif @backends && @backends.size == 1 && @responses[master_backend]
      info "Client disconnected after the master response. Closing master"
      super
    else
      info "Client disconnected. Waiting for all backends to finish"
    end
  end
end