# Copyright 2021-2022 VMware, Inc.
# SPDX-License-Identifier: Apache-2.0
"""
Process related utilities.
"""
import errno
import json
import logging
import pprint
import signal
import weakref
from typing import Any
from typing import Dict
from typing import List
from typing import Optional
import attr
import psutil
from _pytest.pytester import LineMatcher
from pytestshellutils.utils import warn_until
log = logging.getLogger(__name__)
[docs]class MatchString(str):
"""
Simple subclass around ``str`` which provides a ``.matcher`` property.
This ``.matcher`` property is an instance of :py:class:`~_pytest.pytester.LineMatcher`
"""
@property
def matcher(self) -> LineMatcher:
"""
Return an instance of :py:class:`~_pytest.pytester.LineMatcher`.
"""
return LineMatcher(self.splitlines())
[docs]def convert_string_to_match_string(value: Optional[str]) -> Optional[MatchString]:
"""
Convert strings into ``MatchString`` instances.
"""
if isinstance(value, str):
return MatchString(value)
return value
[docs]@attr.s(frozen=True, kw_only=True)
class ProcessResult:
"""
Wrapper class around a subprocess result.
This class serves the purpose of having a common result class which will hold the
resulting data from a subprocess command.
:keyword int returncode:
The returncode returned by the process
:keyword str stdout:
The ``stdout`` returned by the process
:keyword str stderr:
The ``stderr`` returned by the process
:keyword list,tuple cmdline:
The command line used to start the process
:keyword dict data:
The data returned by parsing ``stdout``, when possible.
:keyword str data_key:
When ``stdout`` can be parsed as JSON, sometimes there's a top level key which is not
that interesting. By using ``data_key``, we define that we're actually only interested
on the data structure which is keyed by ``data_key``.
.. admonition:: Note
Cast :py:class:`~pytestshellutils.utils.processes.ProcessResult` to a string to pretty-print it.
"""
returncode: int = attr.ib()
stdout: str = attr.ib(converter=convert_string_to_match_string)
stderr: str = attr.ib(converter=convert_string_to_match_string)
cmdline: Optional[List[str]] = attr.ib(default=None)
data_key: Optional[str] = attr.ib(default=None)
data: Optional[Dict[Any, Any]] = attr.ib()
@returncode.validator
def _validate_returncode(self, attribute: Any, value: int) -> None:
"""
Validate the value type.
"""
if not isinstance(value, int):
raise ValueError(f"'returncode' needs to be an integer, not '{type(value)}'")
@data.default
def _default_data(self) -> Optional[Dict[Any, Any]]:
"""
Try to parse the passed ``stdout`` as JSON as the default data value.
"""
stdout: Optional[str] = self.stdout.strip() if self.stdout else None
if stdout:
try:
data: Optional[Dict[Any, Any]] = json.loads(stdout.strip())
if data and self.data_key and self.data_key in data:
data = data[self.data_key]
return data
except ValueError:
pass
return None
@property
def exitcode(self) -> int:
"""
Return the process returncode.
This property is deprecated and should not be used.
It only exists to support projects that are migrating from
pytest-salt-factories versions. Use ``.returncode`` instead.
"""
warn_until(
"2.0.0",
"The '.exitcode' property is deprecated and will cease to exist after "
"pytest-shell-utilities {version}. Please use '.returncode' instead.",
)
return self.returncode
@property
def json(self) -> Optional[Dict[Any, Any]]:
"""
Return the process output parsed as JSON, if possible.
This property is deprecated and should not be used.
It only exists to support projects that are migrating from
pytest-salt-factories versions. Use ``.data`` instead.
"""
warn_until(
"2.0.0",
"The '.json' property is deprecated and will cease to exist after "
"pytest-shell-utilities {version}. Please use '.data' instead.",
)
return self.data
[docs] def __str__(self) -> str:
"""
String representation of the class.
"""
message = self.__class__.__name__
if self.cmdline:
message += f"\n Command Line: {self.cmdline}"
if self.returncode is not None:
message += f"\n Returncode: {self.returncode}"
if (self.stdout and self.stdout.strip()) or (self.stderr and self.stderr.strip()):
message += "\n Process Output:"
if self.stdout and self.stdout.strip():
message += f"\n >>>>> STDOUT >>>>>\n{self.stdout}\n <<<<< STDOUT <<<<<"
if self.stderr and self.stderr.strip():
message += f"\n >>>>> STDERR >>>>>\n{self.stderr}\n <<<<< STDERR <<<<<"
if self.data:
message += "\n Parsed JSON Data:\n"
message += "\n".join(f" {line}" for line in pprint.pformat(self.data).splitlines())
return message + "\n"
[docs]def collect_child_processes(pid: int) -> List[psutil.Process]:
"""
Try to collect any started child processes of the provided pid.
:param int pid:
The PID of the process
"""
# Let's get the child processes of the started subprocess
children: List[psutil.Process]
try:
parent = psutil.Process(pid)
children = parent.children(recursive=True)
except psutil.NoSuchProcess:
children = []
return children
def _get_cmdline(proc: psutil.Process) -> Optional[Any]:
# pylint: disable=protected-access
try:
return proc._cmdline
except AttributeError:
# Cache the cmdline since that will be inaccessible once the process is terminated
# and we use it in log calls
try:
cmdline = proc.cmdline()
except (psutil.NoSuchProcess, psutil.AccessDenied):
# OSX is more restrictive about the above information
cmdline = None
except OSError: # pragma: no cover
# On Windows we've seen something like:
# File " c: ... \lib\site-packages\pytestsalt\utils\__init__.py", line 182, in terminate_process
# terminate_process_list(process_list, kill=slow_stop is False, slow_stop=slow_stop)
# File " c: ... \lib\site-packages\pytestsalt\utils\__init__.py", line 130, in terminate_process_list
# _terminate_process_list(process_list, kill=kill, slow_stop=slow_stop)
# File " c: ... \lib\site-packages\pytestsalt\utils\__init__.py", line 78, in _terminate_process_list
# cmdline = process.cmdline()
# File " c: ... \lib\site-packages\psutil\__init__.py", line 786, in cmdline
# return self._proc.cmdline()
# File " c: ... \lib\site-packages\psutil\_pswindows.py", line 667, in wrapper
# return fun(self, *args, **kwargs)
# File " c: ... \lib\site-packages\psutil\_pswindows.py", line 745, in cmdline
# ret = cext.proc_cmdline(self.pid, use_peb=True)
# OSError: [WinError 299] Only part of a ReadProcessMemory or WriteProcessMemory request was completed: 'originated from ReadProcessMemory(ProcessParameters)
cmdline = None
except RuntimeError: # pragma: no cover
# Also on windows
# saltfactories\utils\processes\helpers.py:68: in _get_cmdline
# cmdline = proc.as_dict()
# c: ... \lib\site-packages\psutil\__init__.py:634: in as_dict
# ret = meth()
# c: ... \lib\site-packages\psutil\__init__.py:1186: in memory_full_info
# return self._proc.memory_full_info()
# c: ... \lib\site-packages\psutil\_pswindows.py:667: in wrapper
# return fun(self, *args, **kwargs)
# _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
#
# self = <psutil._pswindows.Process object at 0x0000029B7FDA5558>
#
# @wrap_exceptions
# def memory_full_info(self):
# basic_mem = self.memory_info()
# > uss = cext.proc_memory_uss(self.pid)
# E RuntimeError: NtQueryVirtualMemory failed
#
# c: ... \lib\site-packages\psutil\_pswindows.py:806: RuntimeError
cmdline = None
if not cmdline:
try:
cmdline = proc.as_dict()
except psutil.NoSuchProcess:
cmdline = f"<could not be retrived; dead process: {proc}>"
except (psutil.AccessDenied, OSError): # pragma: no cover
cmdline = weakref.proxy(proc)
proc._cmdline = cmdline
return proc._cmdline
# pylint: enable=protected-access
def _terminate_process_list(
process_list: List[psutil.Process], kill: bool = False, slow_stop: bool = False
) -> None:
log.info(
"Terminating process list:\n%s",
pprint.pformat([_get_cmdline(proc) for proc in process_list]),
)
for process in process_list[:]: # Iterate over copy of the list
if not psutil.pid_exists(process.pid):
process_list.remove(process)
continue
try:
if not kill and process.status() == psutil.STATUS_ZOMBIE: # pragma: no cover
# Zombie processes will exit once child processes also exit
continue
if kill:
log.info("Killing process(%s): %s", process.pid, _get_cmdline(process))
process.kill()
else:
log.info("Terminating process(%s): %s", process.pid, _get_cmdline(process))
try:
if slow_stop:
# Allow coverage data to be written down to disk
process.send_signal(signal.SIGTERM)
try:
process.wait(2)
except psutil.TimeoutExpired: # pragma: no cover
if psutil.pid_exists(process.pid):
continue
else:
process.terminate()
except OSError as exc: # pragma: no cover
if exc.errno not in (errno.ESRCH, errno.EACCES):
raise
if not psutil.pid_exists(process.pid):
process_list.remove(process)
except psutil.NoSuchProcess:
process_list.remove(process)
[docs]def terminate_process_list(
process_list: List[psutil.Process], kill: bool = False, slow_stop: bool = False
) -> None:
"""
Terminate a list of processes.
:param ~collections.abc.Iterable process_list:
An iterable of :py:class:`psutil.Process` instances to terminate
:keyword bool kill:
Kill the process instead of terminating it.
:keyword bool slow_stop:
First try to terminate each process in the list, and if termination was not successful, kill it.
"""
def on_process_terminated(proc: psutil.Process) -> None:
log.info(
"Process %s terminated with exit code: %s",
getattr(proc, "_cmdline", proc),
proc.returncode,
)
# Try to terminate processes with the provided kill and slow_stop parameters
log.info("Terminating process list. 1st step. kill: %s, slow stop: %s", kill, slow_stop)
# Remove duplicates from the process list
seen_pids = []
start_count = len(process_list)
for proc in process_list[:]:
if proc.pid in seen_pids:
process_list.remove(proc)
seen_pids.append(proc.pid)
end_count = len(process_list)
if end_count < start_count:
log.debug("Removed %d duplicates from the initial process list", start_count - end_count)
_terminate_process_list(process_list, kill=kill, slow_stop=slow_stop)
psutil.wait_procs(process_list, timeout=5, callback=on_process_terminated)
if process_list:
# If there's still processes to be terminated, retry and kill them if slow_stop is False
log.info(
"Terminating process list. 2nd step. kill: %s, slow stop: %s",
slow_stop is False,
slow_stop,
)
_terminate_process_list(process_list, kill=slow_stop is False, slow_stop=slow_stop)
psutil.wait_procs(process_list, timeout=5, callback=on_process_terminated)
if process_list:
# If there's still processes to be terminated, just kill them, no slow stopping now
log.info("Terminating process list. 3rd step. kill: True, slow stop: False")
_terminate_process_list(process_list, kill=True, slow_stop=False)
psutil.wait_procs(process_list, timeout=5, callback=on_process_terminated)
if process_list:
# In there's still processes to be terminated, log a warning about it
log.warning("Some processes failed to properly terminate: %s", process_list)
[docs]def terminate_process(
pid: Optional[int] = None,
process: Optional[psutil.Process] = None,
children: Optional[List[psutil.Process]] = None,
kill_children: Optional[bool] = None,
slow_stop: bool = False,
) -> None:
"""
Try to terminate/kill the started process.
:keyword int pid:
The PID of the process
:keyword ~psutil.Process process:
An instance of :py:class:`psutil.Process`
:keyword ~collections.abc.Iterable children:
An iterable of :py:class:`psutil.Process` instances, children to the process being terminated
:keyword bool kill_children:
Also try to terminate/kill child processes
:keyword bool slow_stop:
First try to terminate each process in the list, and if termination was not successful, kill it.
"""
children = children or []
process_list: List[psutil.Process] = []
if kill_children is None:
# Always kill children if kill the parent process and kill_children was not set
kill_children = True if slow_stop is False else kill_children
if pid and not process:
try:
process = psutil.Process(pid)
process_list.append(process)
except psutil.NoSuchProcess:
# Process is already gone
process = None
if kill_children:
if process:
children.extend(collect_child_processes(process.pid))
if children:
process_list.extend(children)
if process_list:
if process:
log.info("Stopping process %s and respective children: %s", process, children)
else:
log.info("Terminating process list: %s", process_list)
terminate_process_list(process_list, kill=slow_stop is False, slow_stop=slow_stop)