in lib64/python3.6/dist-packages/pip/_internal/utils/misc.py [0:0]
def call_subprocess(cmd, show_stdout=True, cwd=None,
on_returncode='raise',
command_desc=None,
extra_environ=None, unset_environ=None, spinner=None):
"""
Args:
unset_environ: an iterable of environment variable names to unset
prior to calling subprocess.Popen().
"""
if unset_environ is None:
unset_environ = []
# This function's handling of subprocess output is confusing and I
# previously broke it terribly, so as penance I will write a long comment
# explaining things.
#
# The obvious thing that affects output is the show_stdout=
# kwarg. show_stdout=True means, let the subprocess write directly to our
# stdout. Even though it is nominally the default, it is almost never used
# inside pip (and should not be used in new code without a very good
# reason); as of 2016-02-22 it is only used in a few places inside the VCS
# wrapper code. Ideally we should get rid of it entirely, because it
# creates a lot of complexity here for a rarely used feature.
#
# Most places in pip set show_stdout=False. What this means is:
# - We connect the child stdout to a pipe, which we read.
# - By default, we hide the output but show a spinner -- unless the
# subprocess exits with an error, in which case we show the output.
# - If the --verbose option was passed (= loglevel is DEBUG), then we show
# the output unconditionally. (But in this case we don't want to show
# the output a second time if it turns out that there was an error.)
#
# stderr is always merged with stdout (even if show_stdout=True).
if show_stdout:
stdout = None
else:
stdout = subprocess.PIPE
if command_desc is None:
cmd_parts = []
for part in cmd:
if ' ' in part or '\n' in part or '"' in part or "'" in part:
part = '"%s"' % part.replace('"', '\\"')
cmd_parts.append(part)
command_desc = ' '.join(cmd_parts)
logger.debug("Running command %s", command_desc)
env = os.environ.copy()
if extra_environ:
env.update(extra_environ)
for name in unset_environ:
env.pop(name, None)
try:
proc = subprocess.Popen(
cmd, stderr=subprocess.STDOUT, stdin=subprocess.PIPE,
stdout=stdout, cwd=cwd, env=env,
)
proc.stdin.close()
except Exception as exc:
logger.critical(
"Error %s while executing command %s", exc, command_desc,
)
raise
all_output = []
if stdout is not None:
while True:
line = console_to_str(proc.stdout.readline())
if not line:
break
line = line.rstrip()
all_output.append(line + '\n')
if logger.getEffectiveLevel() <= std_logging.DEBUG:
# Show the line immediately
logger.debug(line)
else:
# Update the spinner
if spinner is not None:
spinner.spin()
try:
proc.wait()
finally:
if proc.stdout:
proc.stdout.close()
if spinner is not None:
if proc.returncode:
spinner.finish("error")
else:
spinner.finish("done")
if proc.returncode:
if on_returncode == 'raise':
if (logger.getEffectiveLevel() > std_logging.DEBUG and
not show_stdout):
logger.info(
'Complete output from command %s:', command_desc,
)
logger.info(
''.join(all_output) +
'\n----------------------------------------'
)
raise InstallationError(
'Command "%s" failed with error code %s in %s'
% (command_desc, proc.returncode, cwd))
elif on_returncode == 'warn':
logger.warning(
'Command "%s" had error code %s in %s',
command_desc, proc.returncode, cwd,
)
elif on_returncode == 'ignore':
pass
else:
raise ValueError('Invalid value: on_returncode=%s' %
repr(on_returncode))
if not show_stdout:
return ''.join(all_output)