Get return value and PID of spawned process using QProcess

import sys
from PyQt4 import QtGui, QtCore
from PyQt4.QtCore import QProcess

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)

    command = "./testCommand.py"
    args = [""]

    #"regular" startDetached : give two arguments, get a boolean
    process=QProcess()
    re=process.startDetached("ls",["."])
    print(re)
    print(type(re))

    #"overload" startDetached : give three arguments, get a tuple(boolean,PID)
    process2=QProcess()
    re,pid=process2.startDetached("ls",["."],".")
    print(re,pid)
    print(type(re),type(pid))

References
https://stackoverflow.com/questions/31519215/pyqt4-qprocess-startdetached-cant-get-return-value-and-pid-of-spawned-proce

Use QProcess to run a program

if self.mosquitto_process is None:
    self.mosquitto_process = QProcess()
self.mosquitto_process.start("mosquitto.cmd")
self.port = utils.pick_free_port()
    _logger().debug('starting server process: %s',
                    ' '.join([self._interpreter, server.__file__,
                              str(self.port)]))
    self._process = QtCore.QProcess()
    self._process.readyRead.connect(self._on_ready_read)
    self._process.setProcessChannelMode(self._process.MergedChannels)
    self._process.finished.connect(self._on_finished)
    self._process.stateChanged.connect(self._on_state_changed)
    self._process.start(
        self._interpreter, (server.__file__, str(self.port)))

proc = QProcess()
    proc.start(*py_proc('print("Hello World")'))
    dev = qtutils.PyQIODevice(proc)
    assert not dev.closed
    with pytest.raises(OSError) as excinfo:
        dev.seek(0)
    assert str(excinfo.value) == 'Random access not allowed!'
    with pytest.raises(OSError) as excinfo:
        dev.tell()
    assert str(excinfo.value) == 'Random access not allowed!'
    proc.waitForFinished(1000)
    proc.kill()
    assert bytes(dev.read()).rstrip() == b'Hello World'

References
https://programtalk.com/python-examples/PyQt5.QtCore.QProcess/

Python timestamp to datetime and vice-versa

Python timestamp to datetime

from datetime import datetime

timestamp = 1545730073
dt_object = datetime.fromtimestamp(timestamp)

print("dt_object =", dt_object)
print("type(dt_object) =", type(dt_object))

Python datetime to timestamp

from datetime import datetime

# current date and time
now = datetime.now()

timestamp = datetime.timestamp(now)
print("timestamp =", timestamp)

References
https://www.programiz.com/python-programming/datetime/timestamp-datetime

Check if a process is running by name and find it’s Process ID in Python using psutil

Check if a process is running

import psutil
def checkIfProcessRunning(processName):
    '''
    Check if there is any running process that contains the given name processName.
    '''
    #Iterate over the all the running process
    for proc in psutil.process_iter():
        try:
            # Check if process name contains the given name string.
            if processName.lower() in proc.name().lower():
                return True
        except (psutil.NoSuchProcess, psutil.AccessDenied, psutil.ZombieProcess):
            pass
    return False;
# Check if any chrome process was running or not.
if checkIfProcessRunning('chrome'):
    print('Yes a chrome process was running')
else:
    print('No chrome process was running')

Find PID (Process ID) of a running process by Name

import psutil
def findProcessIdByName(processName):
    '''
    Get a list of all the PIDs of a all the running process whose name contains
    the given string processName
    '''
    listOfProcessObjects = []
    #Iterate over the all the running process
    for proc in psutil.process_iter():
       try:
           pinfo = proc.as_dict(attrs=['pid', 'name', 'create_time'])
           # Check if process name contains the given name string.
           if processName.lower() in pinfo['name'].lower() :
               listOfProcessObjects.append(pinfo)
       except (psutil.NoSuchProcess, psutil.AccessDenied , psutil.ZombieProcess) :
           pass
    return listOfProcessObjects;
# Find PIDs od all the running instances of process that contains 'chrome' in it's name
listOfProcessIds = findProcessIdByName('chrome')
if len(listOfProcessIds) > 0:
   print('Process Exists | PID and other details are')
   for elem in listOfProcessIds:
       processID = elem['pid']
       processName = elem['name']
       processCreationTime =  time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(elem['create_time']))
       print((processID ,processName,processCreationTime ))
else :
   print('No Running Process found with given text')

References
https://thispointer.com/python-check-if-a-process-is-running-by-name-and-find-its-process-id-pid/