Python signal.CTRL_BREAK_EVENT Examples

def terminate_process(proc: Any, timeout: int = 15) -> None:
    if proc.poll() is None:

        # Sigint (keyboard interupt)
        if sys.platform.startswith("win"):
            proc.send_signal(signal.CTRL_BREAK_EVENT)
        else:
            proc.send_signal(signal.SIGINT)

        try:
            start = time.time()
            while (proc.poll() is None) and (time.time() < (start + timeout)):
                time.sleep(0.02)

        # Flat kill
        finally:
            proc.kill() 

def _default_handler(signum, *args):
        ''' The default signal handler. Don't register with built-in
        signal.signal! This needs to be used on the subprocess await
        death workaround.
        '''
        # All valid cpython windows signals
        sigs = {
            signal.SIGABRT: SIGABRT,
            # signal.SIGFPE: 'fpe', # Don't catch this
            # signal.SIGSEGV: 'segv', # Don't catch this
            # signal.SIGILL: 'illegal', # Don't catch this
            signal.SIGINT: SIGINT,
            signal.SIGTERM: SIGTERM,
            # Note that signal.CTRL_C_EVENT and signal.CTRL_BREAK_EVENT are
            # converted to SIGINT in _await_signal
        }
        
        try:
            exc = sigs[signum]
        except KeyError:
            exc = DaemonikerSignal
            
        _sketch_raise_in_main(exc) 

def test_kill_terminate(self):
        # subprocess.Popen()'s terminate(), kill() and send_signal() do
        # not raise exception after the process is gone. psutil.Popen
        # diverges from that.
        cmd = [PYTHON_EXE, "-c", "import time; time.sleep(60);"]
        with psutil.Popen(cmd, stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE) as proc:
            proc.terminate()
            proc.wait()
            self.assertRaises(psutil.NoSuchProcess, proc.terminate)
            self.assertRaises(psutil.NoSuchProcess, proc.kill)
            self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                              signal.SIGTERM)
            if WINDOWS and sys.version_info >= (2, 7):
                self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                                  signal.CTRL_C_EVENT)
                self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                                  signal.CTRL_BREAK_EVENT) 

def test_kill_terminate(self):
        # subprocess.Popen()'s terminate(), kill() and send_signal() do
        # not raise exception after the process is gone. psutil.Popen
        # diverges from that.
        cmd = [PYTHON_EXE, "-c", "import time; time.sleep(60);"]
        with psutil.Popen(cmd, stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE) as proc:
            proc.terminate()
            proc.wait()
            self.assertRaises(psutil.NoSuchProcess, proc.terminate)
            self.assertRaises(psutil.NoSuchProcess, proc.kill)
            self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                              signal.SIGTERM)
            if WINDOWS and sys.version_info >= (2, 7):
                self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                                  signal.CTRL_C_EVENT)
                self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                                  signal.CTRL_BREAK_EVENT) 

def terminate(self):
    """Tries to do something saner on Windows that the stdlib.

    Windows:
      self.detached/CREATE_NEW_PROCESS_GROUP determines what can be used:
      - If set, only SIGBREAK can be sent and it is sent to a single process.
      - If not set, in theory only SIGINT can be used and *all processes* in
         the processgroup receive it. In practice, we just kill the process.
      See http://msdn.microsoft.com/library/windows/desktop/ms683155.aspx
      The default on Windows is to call TerminateProcess() always, which is not
      useful.

    On Posix, always send SIGTERM.
    """
    try:
      if sys.platform == 'win32' and self.detached:
        return self.send_signal(signal.CTRL_BREAK_EVENT)
      super(Popen, self).terminate()
    except OSError:
      # The function will throw if the process terminated in-between. Swallow
      # this.
      pass 

def kill(self, sig):
        '''Sends a Unix signal to the subprocess.

        Use constants from the :mod:`signal` module to specify which signal.
        '''
        if sys.platform == 'win32':
            if sig in [signal.SIGINT, signal.CTRL_C_EVENT]:
                sig = signal.CTRL_C_EVENT
            elif sig in [signal.SIGBREAK, signal.CTRL_BREAK_EVENT]:
                sig = signal.CTRL_BREAK_EVENT
            else:
                sig = signal.SIGTERM

        os.kill(self.proc.pid, sig) 

def test_kill_terminate(self):
        # subprocess.Popen()'s terminate(), kill() and send_signal() do
        # not raise exception after the process is gone. psutil.Popen
        # diverges from that.
        cmd = [PYTHON_EXE, "-c", "import time; time.sleep(60);"]
        with psutil.Popen(cmd, stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE) as proc:
            proc.terminate()
            proc.wait()
            self.assertRaises(psutil.NoSuchProcess, proc.terminate)
            self.assertRaises(psutil.NoSuchProcess, proc.kill)
            self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                              signal.SIGTERM)
            if WINDOWS and sys.version_info >= (2, 7):
                self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                                  signal.CTRL_C_EVENT)
                self.assertRaises(psutil.NoSuchProcess, proc.send_signal,
                                  signal.CTRL_BREAK_EVENT) 

def reap_process_group(*args):
    def sigterm_handler(*args):
        # Give a one-second grace period for other processes to clean up.
        time.sleep(SIGTERM_GRACE_PERIOD_SECONDS)
        # SIGKILL the pgroup (including ourselves) as a last-resort.
        if sys.platform == "win32":
            atexit.unregister(sigterm_handler)
            os.kill(0, signal.CTRL_BREAK_EVENT)
        else:
            os.killpg(0, signal.SIGKILL)

    # Set a SIGTERM handler to handle SIGTERMing ourselves with the group.
    if sys.platform == "win32":
        atexit.register(sigterm_handler)
    else:
        signal.signal(signal.SIGTERM, sigterm_handler)

    # Our parent must have died, SIGTERM the group (including ourselves).
    if sys.platform == "win32":
        os.kill(0, signal.CTRL_C_EVENT)
    else:
        os.killpg(0, signal.SIGTERM) 

def process_stop(self):
        """Stop soapy_power process"""
        with self._shutdown_lock:
            if self.process:
                if self.process.poll() is None:
                    try:
                        if sys.platform == 'win32':
                            self.process.send_signal(signal.CTRL_BREAK_EVENT)
                        else:
                            self.process.terminate()
                    except ProcessLookupError:
                        pass
                self.process.wait()
                self.process = None

                # Close pipe used for communication with soapy_power process
                self.pipe_read.close()

                self.pipe_read = None
                self.pipe_read_fd = None
                self.pipe_write_fd = None
                self.pipe_write_handle = None 

def test_sig():
    """Basic SIGTERM"""
    proc = sp.Popen(
        [sys.executable, "tests/fake_main.py"],
        stdout=sp.PIPE,
        stderr=sp.STDOUT,
        creationflags=sp.CREATE_NEW_PROCESS_GROUP,
    )
    time.sleep(0.5)
    # proc.send_signal(signal.CTRL_BREAK_EVENT)
    # os.kill(proc.pid, signal.CTRL_C_EVENT)
    os.kill(proc.pid, signal.CTRL_BREAK_EVENT)
    print("Send signal")
    proc.wait(timeout=5)
    stdout = proc.stdout.read().decode()
    print(stdout)
    assert proc.returncode == 0

    expected = [
        "Entering run()",
        "Entering shutdown phase",
        "Cancelling pending tasks",
        "Closing the loop",
        "Bye!",
    ]

    for phrase in expected:
        assert phrase in stdout 

def send_sigint(self) -> None:
        """Send a SIGINT to the process similar to if <Ctrl>+C were pressed"""
        import signal
        if sys.platform.startswith('win'):
            # cmd2 started the Windows process in a new process group. Therefore
            # a CTRL_C_EVENT can't be sent to it. Send a CTRL_BREAK_EVENT instead.
            self._proc.send_signal(signal.CTRL_BREAK_EVENT)
        else:
            # Since cmd2 uses shell=True in its Popen calls, we need to send the SIGINT to
            # the whole process group to make sure it propagates further than the shell
            try:
                group_id = os.getpgid(self._proc.pid)
                os.killpg(group_id, signal.SIGINT)
            except ProcessLookupError:
                return 

def test_cleanup_on_sigterm_sig_break(testdir, setup):
    # worth a read: https://stefan.sofa-rockers.org/2013/08/15/handling-sub-process-hierarchies-python-linux-os-x/
    script = testdir.makepyfile('''
import os, signal, subprocess, sys, time

def test_run():
    proc = subprocess.Popen(
        [sys.executable, __file__],
        stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
        creationflags=subprocess.CREATE_NEW_PROCESS_GROUP, shell=True
    )
    time.sleep(1)
    proc.send_signal(signal.CTRL_BREAK_EVENT)
    stdout, stderr = proc.communicate()
    assert not stderr
    assert stdout in [b"^C", b"", b"captured IOError(4, 'Interrupted function call')\\n"]

if __name__ == "__main__":
    from pytest_cov.embed import cleanup_on_signal, cleanup
    ''' + setup[0] + '''

    try:
        time.sleep(10)
    except BaseException as exc:
        print("captured %r" % exc)
''')

    result = testdir.runpytest('-vv',
                               '--cov=%s' % script.dirpath(),
                               '--cov-report=term-missing',
                               script)

    result.stdout.fnmatch_lines([
        '*- coverage: platform *, python * -*',
        'test_cleanup_on_sigterm* %s' % setup[1],
        '*1 passed*'
    ])
    assert result.ret == 0 

def send_signal(self, sig):
            """Send a signal to the process
            """
            if sig == signal.SIGTERM:
                self.terminate()
            elif sig == signal.CTRL_C_EVENT:
                os.kill(self.pid, signal.CTRL_C_EVENT)
            elif sig == signal.CTRL_BREAK_EVENT:
                os.kill(self.pid, signal.CTRL_BREAK_EVENT)
            else:
                raise ValueError("Unsupported signal: {}".format(sig)) 

def _ctrl_handler(sig):
    """Handle a sig event and return 0 to terminate the process"""
    if sig == signal.CTRL_C_EVENT:
        pass
    elif sig == signal.CTRL_BREAK_EVENT:
        pass
    else:
        print("UNKNOWN EVENT")
    return 0 

def test_CTRL_BREAK_EVENT(self):
        self._kill_with_event(signal.CTRL_BREAK_EVENT, "CTRL_BREAK_EVENT") 

def test_ctrl_signals(self):
        p = psutil.Process(get_test_subprocess().pid)
        p.send_signal(signal.CTRL_C_EVENT)
        p.send_signal(signal.CTRL_BREAK_EVENT)
        p.kill()
        p.wait()
        self.assertRaises(psutil.NoSuchProcess,
                          p.send_signal, signal.CTRL_C_EVENT)
        self.assertRaises(psutil.NoSuchProcess,
                          p.send_signal, signal.CTRL_BREAK_EVENT) 

def send_signal(self, sig):
            """Send a signal to the process
            """
            if sig == signal.SIGTERM:
                self.terminate()
            elif sig == signal.CTRL_C_EVENT:
                os.kill(self.pid, signal.CTRL_C_EVENT)
            elif sig == signal.CTRL_BREAK_EVENT:
                os.kill(self.pid, signal.CTRL_BREAK_EVENT)
            else:
                raise ValueError("Unsupported signal: {}".format(sig)) 

def send_signal(self, sig):
            """Send a signal to the process
            """
            if sig == signal.SIGTERM:
                self.terminate()
            elif sig == signal.CTRL_C_EVENT:
                os.kill(self.pid, signal.CTRL_C_EVENT)
            elif sig == signal.CTRL_BREAK_EVENT:
                os.kill(self.pid, signal.CTRL_BREAK_EVENT)
            else:
                raise ValueError("Unsupported signal: {}".format(sig)) 

def send_signal(self, sig):
            """Send a signal to the process
            """
            if sig == signal.SIGTERM:
                self.terminate()
            elif sig == signal.CTRL_C_EVENT:
                os.kill(self.pid, signal.CTRL_C_EVENT)
            elif sig == signal.CTRL_BREAK_EVENT:
                os.kill(self.pid, signal.CTRL_BREAK_EVENT)
            else:
                raise ValueError("Unsupported signal: {}".format(sig)) 

def send_signal(self, sig):
            """Send a signal to the process
            """
            if sig == signal.SIGTERM:
                self.terminate()
            elif sig == signal.CTRL_C_EVENT:
                os.kill(self.pid, signal.CTRL_C_EVENT)
            elif sig == signal.CTRL_BREAK_EVENT:
                os.kill(self.pid, signal.CTRL_BREAK_EVENT)
            else:
                raise ValueError("Unsupported signal: {}".format(sig)) 

def _ctrl_handler(sig):
    """Handle a sig event and return 0 to terminate the process"""
    if sig == signal.CTRL_C_EVENT:
        pass
    elif sig == signal.CTRL_BREAK_EVENT:
        pass
    else:
        print("UNKNOWN EVENT")
    return 0 

def test_CTRL_BREAK_EVENT(self):
        self._kill_with_event(signal.CTRL_BREAK_EVENT, "CTRL_BREAK_EVENT") 

def send_signal(self, sig):
            """Send a signal to the process
            """
            if sig == signal.SIGTERM:
                self.terminate()
            elif sig == signal.CTRL_C_EVENT:
                os.kill(self.pid, signal.CTRL_C_EVENT)
            elif sig == signal.CTRL_BREAK_EVENT:
                os.kill(self.pid, signal.CTRL_BREAK_EVENT)
            else:
                raise ValueError("Unsupported signal: {}".format(sig)) 

def send_signal(self, sig):
            """Send a signal to the process
            """
            if sig == signal.SIGTERM:
                self.terminate()
            elif sig == signal.CTRL_C_EVENT:
                os.kill(self.pid, signal.CTRL_C_EVENT)
            elif sig == signal.CTRL_BREAK_EVENT:
                os.kill(self.pid, signal.CTRL_BREAK_EVENT)
            else:
                raise ValueError("Unsupported signal: {}".format(sig)) 

def terminate(self):
            if isinstance(self.stdin, io.IOBase):
                self.stdin.close()
            if self._use_signals:
                self.send_signal(signal.CTRL_BREAK_EVENT)
            else:
                super(ConsolePopen, self).terminate() 

def kill_command(pid):
    """kill command"""
    if sys.platform == 'win32':
        process = psutil.Process(pid=pid)
        process.send_signal(signal.CTRL_BREAK_EVENT)
    else:
        cmds = ['kill', str(pid)]
        call(cmds) 

def test_signal_waiting(self):
        ''' Fixture thine self.
        '''
        proc1 = ProcFixture(signal.SIGINT)
        proc2 = ProcFixture(signal.SIGTERM)
        proc3 = ProcFixture(signal.SIGABRT)
        proc4 = ProcFixture(signal.CTRL_C_EVENT)
        proc5 = ProcFixture(signal.CTRL_BREAK_EVENT)
        
        self.assertEqual(_await_signal(proc1), signal.SIGINT)
        self.assertEqual(_await_signal(proc2), signal.SIGTERM)
        self.assertEqual(_await_signal(proc3), signal.SIGABRT)
        self.assertEqual(_await_signal(proc4), signal.SIGINT)
        self.assertEqual(_await_signal(proc5), signal.SIGINT) 

def _await_signal(process):
    ''' Waits for the process to die, and then returns the exit code for
    the process, converting CTRL_C_EVENT and CTRL_BREAK_EVENT into
    SIGINT.
    '''
    # Note that this is implemented with a busy wait
    process.wait()
    code = process.returncode
    
    if code == signal.CTRL_C_EVENT:
        code = signal.SIGINT
    elif code == signal.CTRL_BREAK_EVENT:
        code = signal.SIGINT
    
    return code 

def interrupt_ipc_subprocess(proc):
    ''' Send CTRL_BREAK on Windows, SIGINT on other platforms '''

    if sys.platform == 'win32':
        proc.send_signal(signal.CTRL_BREAK_EVENT)  # pylint: disable=no-member
    else:
        proc.send_signal(signal.SIGINT) 

def _ctrl_handler(sig):
    """Handle a sig event and return 0 to terminate the process"""
    if sig == signal.CTRL_C_EVENT:
        pass
    elif sig == signal.CTRL_BREAK_EVENT:
        pass
    else:
        print("UNKNOWN EVENT")
    return 0