1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
import errno
import os
import select
import socket as pysocket
import struct
try:
from ..transport import NpipeSocket
except ImportError:
NpipeSocket = type(None)
STDOUT = 1
STDERR = 2
class SocketError(Exception):
pass
# NpipeSockets have their own error types
# pywintypes.error: (109, 'ReadFile', 'The pipe has been ended.')
NPIPE_ENDED = 109
def read(socket, n=4096):
"""
Reads at most n bytes from socket
"""
recoverable_errors = (errno.EINTR, errno.EDEADLK, errno.EWOULDBLOCK)
if not isinstance(socket, NpipeSocket):
select.select([socket], [], [])
try:
if hasattr(socket, 'recv'):
return socket.recv(n)
if isinstance(socket, getattr(pysocket, 'SocketIO')):
return socket.read(n)
return os.read(socket.fileno(), n)
except OSError as e:
if e.errno not in recoverable_errors:
raise
except Exception as e:
is_pipe_ended = (isinstance(socket, NpipeSocket) and
len(e.args) > 0 and
e.args[0] == NPIPE_ENDED)
if is_pipe_ended:
# npipes don't support duplex sockets, so we interpret
# a PIPE_ENDED error as a close operation (0-length read).
return ''
raise
def read_exactly(socket, n):
"""
Reads exactly n bytes from socket
Raises SocketError if there isn't enough data
"""
data = bytes()
while len(data) < n:
next_data = read(socket, n - len(data))
if not next_data:
raise SocketError("Unexpected EOF")
data += next_data
return data
def next_frame_header(socket):
"""
Returns the stream and size of the next frame of data waiting to be read
from socket, according to the protocol defined here:
https://docs.docker.com/engine/api/v1.24/#attach-to-a-container
"""
try:
data = read_exactly(socket, 8)
except SocketError:
return (-1, -1)
stream, actual = struct.unpack('>BxxxL', data)
return (stream, actual)
def frames_iter(socket, tty):
"""
Return a generator of frames read from socket. A frame is a tuple where
the first item is the stream number and the second item is a chunk of data.
If the tty setting is enabled, the streams are multiplexed into the stdout
stream.
"""
if tty:
return ((STDOUT, frame) for frame in frames_iter_tty(socket))
else:
return frames_iter_no_tty(socket)
def frames_iter_no_tty(socket):
"""
Returns a generator of data read from the socket when the tty setting is
not enabled.
"""
while True:
(stream, n) = next_frame_header(socket)
if n < 0:
break
while n > 0:
result = read(socket, n)
if result is None:
continue
data_length = len(result)
if data_length == 0:
# We have reached EOF
return
n -= data_length
yield (stream, result)
def frames_iter_tty(socket):
"""
Return a generator of data read from the socket when the tty setting is
enabled.
"""
while True:
result = read(socket)
if len(result) == 0:
# We have reached EOF
return
yield result
def consume_socket_output(frames, demux=False):
"""
Iterate through frames read from the socket and return the result.
Args:
demux (bool):
If False, stdout and stderr are multiplexed, and the result is the
concatenation of all the frames. If True, the streams are
demultiplexed, and the result is a 2-tuple where each item is the
concatenation of frames belonging to the same stream.
"""
if demux is False:
# If the streams are multiplexed, the generator returns strings, that
# we just need to concatenate.
return bytes().join(frames)
# If the streams are demultiplexed, the generator yields tuples
# (stdout, stderr)
out = [None, None]
for frame in frames:
# It is guaranteed that for each frame, one and only one stream
# is not None.
assert frame != (None, None)
if frame[0] is not None:
if out[0] is None:
out[0] = frame[0]
else:
out[0] += frame[0]
else:
if out[1] is None:
out[1] = frame[1]
else:
out[1] += frame[1]
return tuple(out)
def demux_adaptor(stream_id, data):
"""
Utility to demultiplex stdout and stderr when reading frames from the
socket.
"""
if stream_id == STDOUT:
return (data, None)
elif stream_id == STDERR:
return (None, data)
else:
raise ValueError(f'{stream_id} is not a valid stream')
|
