def test_subprocess_print():
"""printing from forked mp.Process"""
with new_kernel() as kc:
iopub = kc.iopub_channel
_check_mp_mode(kc, expected=False)
flush_channels(kc)
np = 5
code = '\n'.join([
"from __future__ import print_function",
"import multiprocessing as mp",
"pool = [mp.Process(target=print, args=('hello', i,)) for i in range(%i)]"
% np, "for p in pool: p.start()", "for p in pool: p.join()"
])
expected = '\n'.join(["hello %s" % i for i in range(np)]) + '\n'
msg_id, content = execute(kc=kc, code=code)
stdout, stderr = assemble_output(iopub)
nt.assert_equal(stdout.count("hello"), np, stdout)
for n in range(np):
nt.assert_equal(stdout.count(str(n)), 1, stdout)
nt.assert_equal(stderr, '')
_check_mp_mode(kc, expected=False)
_check_mp_mode(kc, expected=False, stream="stderr")
def _check_mp_mode(kc, expected=False, stream="stdout"):
execute(kc=kc, code="import sys")
flush_channels(kc)
msg_id, content = execute(kc=kc,
code="print (sys.%s._check_mp_mode())" % stream)
stdout, stderr = assemble_output(kc.iopub_channel)
nt.assert_equal(eval(stdout.strip()), expected)
def test_subprocess_print():
"""printing from forked mp.Process"""
with new_kernel() as kc:
iopub = kc.iopub_channel
_check_mp_mode(kc, expected=False)
flush_channels(kc)
np = 5
code = '\n'.join([
"from __future__ import print_function",
"import multiprocessing as mp",
"pool = [mp.Process(target=print, args=('hello', i,)) for i in range(%i)]" % np,
"for p in pool: p.start()",
"for p in pool: p.join()"
])
expected = '\n'.join([
"hello %s" % i for i in range(np)
]) + '\n'
msg_id, content = execute(kc=kc, code=code)
stdout, stderr = assemble_output(iopub)
nt.assert_equal(stdout.count("hello"), np, stdout)
for n in range(np):
nt.assert_equal(stdout.count(str(n)), 1, stdout)
nt.assert_equal(stderr, '')
_check_mp_mode(kc, expected=False)
_check_mp_mode(kc, expected=False, stream="stderr")
def _check_mp_mode(kc, expected=False, stream="stdout"):
execute(kc=kc, code="import sys")
flush_channels(kc)
msg_id, content = execute(
kc=kc,
code="print (sys.%s._check_mp_mode())" % stream
)
stdout, stderr = assemble_output(kc.iopub_channel)
nt.assert_equal(eval(stdout.strip()), expected)
def new_kernel():
"""start a kernel in a subprocess, and wait for it to be ready
Returns
-------
kernel_manager: connected KernelManager instance
"""
KM = KernelManager()
KM.start_kernel(stdout=PIPE, stderr=PIPE)
KC = KM.client()
KC.start_channels()
# wait for kernel to be ready
KC.shell_channel.execute("import sys")
KC.shell_channel.get_msg(block=True, timeout=STARTUP_TIMEOUT)
flush_channels(KC)
try:
yield KC
finally:
KC.stop_channels()
KM.shutdown_kernel()
def new_kernel():
"""start a kernel in a subprocess, and wait for it to be ready
Returns
-------
kernel_manager: connected KernelManager instance
"""
KM = KernelManager()
KM.start_kernel(stdout=PIPE, stderr=PIPE)
KC = KM.client()
KC.start_channels()
# wait for kernel to be ready
KC.shell_channel.execute("import sys")
KC.shell_channel.get_msg(block=True, timeout=STARTUP_TIMEOUT)
flush_channels(KC)
try:
yield KC
finally:
KC.stop_channels()
KM.shutdown_kernel()
