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
|
# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
# For details: https://github.com/nedbat/coveragepy/blob/master/NOTICE.txt
"""Monkey-patching to add multiprocessing support for coverage.py"""
import multiprocessing
import multiprocessing.process
import os
import os.path
import sys
import traceback
from typing import Any, Dict
# An attribute that will be set on the module to indicate that it has been
# monkey-patched.
PATCHED_MARKER = "_coverage$patched"
OriginalProcess = multiprocessing.process.BaseProcess
original_bootstrap = OriginalProcess._bootstrap # type: ignore[attr-defined]
class ProcessWithCoverage(OriginalProcess): # pylint: disable=abstract-method
"""A replacement for multiprocess.Process that starts coverage."""
def _bootstrap(self, *args, **kwargs): # type: ignore[no-untyped-def]
"""Wrapper around _bootstrap to start coverage."""
try:
from coverage import Coverage # avoid circular import
cov = Coverage(data_suffix=True, auto_data=True)
cov._warn_preimported_source = False
cov.start()
debug = cov._debug
assert debug is not None
if debug.should("multiproc"):
debug.write("Calling multiprocessing bootstrap")
except Exception:
print("Exception during multiprocessing bootstrap init:")
traceback.print_exc(file=sys.stdout)
sys.stdout.flush()
raise
try:
return original_bootstrap(self, *args, **kwargs)
finally:
if debug.should("multiproc"):
debug.write("Finished multiprocessing bootstrap")
cov.stop()
cov.save()
if debug.should("multiproc"):
debug.write("Saved multiprocessing data")
class Stowaway:
"""An object to pickle, so when it is unpickled, it can apply the monkey-patch."""
def __init__(self, rcfile: str) -> None:
self.rcfile = rcfile
def __getstate__(self) -> Dict[str, str]:
return {"rcfile": self.rcfile}
def __setstate__(self, state: Dict[str, str]) -> None:
patch_multiprocessing(state["rcfile"])
def patch_multiprocessing(rcfile: str) -> None:
"""Monkey-patch the multiprocessing module.
This enables coverage measurement of processes started by multiprocessing.
This involves aggressive monkey-patching.
`rcfile` is the path to the rcfile being used.
"""
if hasattr(multiprocessing, PATCHED_MARKER):
return
OriginalProcess._bootstrap = ProcessWithCoverage._bootstrap # type: ignore[attr-defined]
# Set the value in ProcessWithCoverage that will be pickled into the child
# process.
os.environ["COVERAGE_RCFILE"] = os.path.abspath(rcfile)
# When spawning processes rather than forking them, we have no state in the
# new process. We sneak in there with a Stowaway: we stuff one of our own
# objects into the data that gets pickled and sent to the sub-process. When
# the Stowaway is unpickled, it's __setstate__ method is called, which
# re-applies the monkey-patch.
# Windows only spawns, so this is needed to keep Windows working.
try:
from multiprocessing import spawn
original_get_preparation_data = spawn.get_preparation_data
except (ImportError, AttributeError):
pass
else:
def get_preparation_data_with_stowaway(name: str) -> Dict[str, Any]:
"""Get the original preparation data, and also insert our stowaway."""
d = original_get_preparation_data(name)
d["stowaway"] = Stowaway(rcfile)
return d
spawn.get_preparation_data = get_preparation_data_with_stowaway
setattr(multiprocessing, PATCHED_MARKER, True)
|
