1212 NpipeSocket = type (None )
1313
1414
15+ STDOUT = 1
16+ STDERR = 2
17+
18+
1519class SocketError (Exception ):
1620 pass
1721
@@ -51,28 +55,43 @@ def read_exactly(socket, n):
5155 return data
5256
5357
54- def next_frame_size (socket ):
58+ def next_frame_header (socket ):
5559 """
56- Returns the size of the next frame of data waiting to be read from socket,
57- according to the protocol defined here:
60+ Returns the stream and size of the next frame of data waiting to be read
61+ from socket, according to the protocol defined here:
5862
59- https://docs.docker.com/engine/reference/ api/docker_remote_api_v1 .24/#/ attach-to-a-container
63+ https://docs.docker.com/engine/api/v1 .24/#attach-to-a-container
6064 """
6165 try :
6266 data = read_exactly (socket , 8 )
6367 except SocketError :
64- return - 1
68+ return (- 1 , - 1 )
69+
70+ stream , actual = struct .unpack ('>BxxxL' , data )
71+ return (stream , actual )
72+
6573
66- _ , actual = struct .unpack ('>BxxxL' , data )
67- return actual
74+ def frames_iter (socket , tty ):
75+ """
76+ Return a generator of frames read from socket. A frame is a tuple where
77+ the first item is the stream number and the second item is a chunk of data.
78+
79+ If the tty setting is enabled, the streams are multiplexed into the stdout
80+ stream.
81+ """
82+ if tty :
83+ return ((STDOUT , frame ) for frame in frames_iter_tty (socket ))
84+ else :
85+ return frames_iter_no_tty (socket )
6886
6987
70- def frames_iter (socket ):
88+ def frames_iter_no_tty (socket ):
7189 """
72- Returns a generator of frames read from socket
90+ Returns a generator of data read from the socket when the tty setting is
91+ not enabled.
7392 """
7493 while True :
75- n = next_frame_size (socket )
94+ ( stream , n ) = next_frame_header (socket )
7695 if n < 0 :
7796 break
7897 while n > 0 :
@@ -84,17 +103,67 @@ def frames_iter(socket):
84103 # We have reached EOF
85104 return
86105 n -= data_length
87- yield result
106+ yield ( stream , result )
88107
89108
90- def socket_raw_iter (socket ):
109+ def frames_iter_tty (socket ):
91110 """
92- Returns a generator of data read from the socket.
93- This is used for non-multiplexed streams .
111+ Return a generator of data read from the socket when the tty setting is
112+ enabled .
94113 """
95114 while True :
96115 result = read (socket )
97116 if len (result ) == 0 :
98117 # We have reached EOF
99118 return
100119 yield result
120+
121+
122+ def consume_socket_output (frames , demux = False ):
123+ """
124+ Iterate through frames read from the socket and return the result.
125+
126+ Args:
127+
128+ demux (bool):
129+ If False, stdout and stderr are multiplexed, and the result is the
130+ concatenation of all the frames. If True, the streams are
131+ demultiplexed, and the result is a 2-tuple where each item is the
132+ concatenation of frames belonging to the same stream.
133+ """
134+ if demux is False :
135+ # If the streams are multiplexed, the generator returns strings, that
136+ # we just need to concatenate.
137+ return six .binary_type ().join (frames )
138+
139+ # If the streams are demultiplexed, the generator yields tuples
140+ # (stdout, stderr)
141+ out = [None , None ]
142+ for frame in frames :
143+ # It is guaranteed that for each frame, one and only one stream
144+ # is not None.
145+ assert frame != (None , None )
146+ if frame [0 ] is not None :
147+ if out [0 ] is None :
148+ out [0 ] = frame [0 ]
149+ else :
150+ out [0 ] += frame [0 ]
151+ else :
152+ if out [1 ] is None :
153+ out [1 ] = frame [1 ]
154+ else :
155+ out [1 ] += frame [1 ]
156+ return tuple (out )
157+
158+
159+ def demux_adaptor (stream_id , data ):
160+ """
161+ Utility to demultiplex stdout and stderr when reading frames from the
162+ socket.
163+ """
164+ if stream_id == STDOUT :
165+ return (data , None )
166+ elif stream_id == STDERR :
167+ return (None , data )
168+ else :
169+ raise ValueError ('{0} is not a valid stream' .format (stream_id ))
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