Error 255 python

You can set an exit code for a process via sys.exit() and retrieve the exit code via the exitcode attribute on the multiprocessing.Process class. In this tutorial you will discover how to get and s…

You can set an exit code for a process via sys.exit() and retrieve the exit code via the exitcode attribute on the multiprocessing.Process class.

In this tutorial you will discover how to get and set exit codes for processes in Python.

Let’s get started.

A process is a running instance of a computer program.

Every Python program is executed in a Process, which is a new instance of the Python interpreter. This process has the name MainProcess and has one thread used to execute the program instructions called the MainThread. Both processes and threads are created and managed by the underlying operating system.

Sometimes we may need to create new child processes in our program in order to execute code concurrently.

Python provides the ability to create and manage new processes via the multiprocessing.Process class.

In multiprocessing, we may need to report the success or failure of a task executed by a child process to other processes.

This can be achieved using exit codes.

What are exit codes and how can we use them between processes in Python?

How to Use Exit Codes in Python

An exit code or exit status is a way for one process to share with another whether it is finished and if so whether it finished successfully or not.

The exit status of a process in computer programming is a small number passed from a child process (or callee) to a parent process (or caller) when it has finished executing a specific procedure or delegated task.

— Exit status, Wikipedia.

An exit code is typically an integer value to represent success or failure of the process, but may also have an associated string message.

Let’s take a closer look at how we might set an exit code in a process and how another process might check the exit code of a process.

How to Set an Exit Code

A process can set the exit code automatically or explicitly.

For example, if the process exits normally, the exit code will be set to zero. If the process terminated with an error or exception, the exit code will be set to one.

A process can also set its exit code when explicitly exiting.

This can be achieved by calling the sys.exit() function and passing the exit code as an argument.

The sys.exit() function will raise a SystemExit exception in the current process, which will terminate the process.

The optional argument arg can be an integer giving the exit status (defaulting to zero), or another type of object.

— sys — System-specific parameters and functions

This function must be called in the main thread of the process and assumes that the SystemExit exception is not handled.

An argument value of 0 indicates a successful exit.

For example:

...

# exit successfully

sys.exit(0)

This is the default value of the argument and does not need to be specified.

For example:

...

# exit successfully

sys.exit()

Passing a value of None as an argument will also be interpreted as a successful exit.

For example:

...

# exit successfully

sys.exit(None)

A positive integer value indicates an unsuccessful exit, typically a value of one.

For example:

...

# exit unsuccessfully

sys.exit(1)

Alternatively, a string message may be provided as an argument.

This will be interpreted as an unsuccessful exit, e.g. a value of one, and the message will be reported on stderr.

For example:

...

# exit unsuccessfully

sys.exit(‘Something bad happened’)

You can learn more about the sys.exit() function in the tutorial:

  • Exit a Process with sys.exit() in Python

How to Get An Exit Code

Another process can get the exit code of a process via the “exitcode” attribute of the multiprocessing.Process instance for the process.

For example:

...

# get the exit code

code = process.exitcode

This means that we require a multiprocessing.Process instance for the process. For example, we may hang on to the process instance when creating the child process.

The exitcode attribute contains the value set by the process calling sys.exit(), or the value set automatically if the process ended normally or with an error.

If the child’s run() method returned normally, the exit code will be 0. If it terminated via sys.exit() with an integer argument N, the exit code will be N.

— multiprocessing — Process-based parallelism

If the process has not yet terminated, the exitcode value will not be set and will have the value None.

Common Exit Code Values

We may set exit codes for a process that are meaningful to the application.

This allows one process to communicate with another process regarding its specific status upon exit.

Additionally, there are also some commonly used exit code values.

For example, the integer value is typically between 0-255 and values 0-127 may be reserved for common situations or errors.

If it is an integer, zero is considered “successful termination” and any nonzero value is considered “abnormal termination” by shells and the like. Most systems require it to be in the range 0–127, and produce undefined results otherwise.

— sys — System-specific parameters and functions

For example:

  • 0, None: Success
  • 1: Error
  • 2: Command line syntax errors
  • 120: Error during process cleanup.
  • 255: Exit code out of range.

A negative exit code may be assigned to a process if the process was terminated via a specific signal.

If it was terminated by signal N, the exit code will be the negative value -N.

— multiprocessing — Process-based parallelism

Now that we know how to get and set exit codes for a process, let’s look at some worked examples.

Confused by the multiprocessing module API?
Download my FREE PDF cheat sheet

Explicit Exit Codes

This section provides examples of explicitly setting an exit code when terminating a process.

Example of Successful Exit Code

We can explore setting a successful exit code in a child process.

In this example we will create a child process to exit a custom function. The child process will block for one second, and then exit with an explicitly successful exit code.

First, we can define the function to execute in the child function.

The function will sleep for a second, then call the sys.exit() function with an argument of zero to indicate a successful exit.

The task() function below implements this.

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

    # exit successfully

    exit(0)

Next, in the main process, we will configure a new process instance to execute our task() function.

...

# configure a new process

child = Process(target=task)

The process is then started, and the main process blocks until the child process terminates.

...

# start the child process

child.start()

# wait for the child process to finish

child.join()

Finally, the main process retrieves the exit code for the child process and reports the value.

...

# check the exit code for the child process

code = child.exitcode

print(f‘Child exit code: {code}’)

Tying this together, the complete example is listed below.

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# SuperFastPython.com

# example of a successful exit code

from time import sleep

from multiprocessing import Process

from sys import exit

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

    # exit successfully

    exit(0)

# protect the entry point

if __name__ == ‘__main__’:

    # configure a new process

    child = Process(target=task)

    # start the child process

    child.start()

    # wait for the child process to finish

    child.join()

    # check the exit code for the child process

    code = child.exitcode

    print(f‘Child exit code: {code}’)

Running the example first creates and starts the child process.

The main process then blocks until the child process terminates.

The child process sleeps for one second, then exits with an exit code of zero, indicating success.

The child process terminates then the main process continues on. It retrieves the exit code from the child process and reports the value.

In this case, we can see it has the value zero that we set in the child process when calling exit().

Next, let’s look at an example of an unsuccessful exit code.

Example of Unsuccessful Exit Code

We can explore an unsuccessful exit code.

Recall that any value other than zero indicates an unsuccessful end to the process.

We can update the example from the previous section so that the process calls exit() with a value of one.

...

# exit unsuccessfully

exit(1)

The updated task() function with this change is listed below.

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

    # exit unsuccessfully

    exit(1)

Tying this together, the complete example is listed below.

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# SuperFastPython.com

# example of an unsuccessful exit code

from time import sleep

from multiprocessing import Process

from sys import exit

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

    # exit unsuccessfully

    exit(1)

# protect the entry point

if __name__ == ‘__main__’:

    # configure a new process

    child = Process(target=task)

    # start the child process

    child.start()

    # wait for the child process to finish

    child.join()

    # check the exit code for the child process

    code = child.exitcode

    print(f‘Child exit code: {code}’)

Running the example first creates and starts the child process.

The main process then blocks until the child process terminates.

The child process sleeps for one second, then exits with an exit code of one, indicating an unsuccessful exit.

The child process terminates then the main process continues on. It retrieves the exit code from the child process and reports the value.

In this case, we can see it has the value of one that we set in the child process when calling exit().

Next, let’s look at an example of an unsuccessful exit code with a message.

Example of Error Message Exit Code

We can explore setting a string message as an exit code.

Recall, setting a string message as an exit code will indicate an unsuccessful exit, setting an exit code of one and reporting the string message on standard error (stderr).

We can update the previous example to set a string message when calling sys.exit().

...

# exit unsuccessfully with a message

exit(‘Something bad happened’)

The updated task() function with this change is listed below.

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

    # exit unsuccessfully with a message

    exit(‘Something bad happened’)

Tying this together, the complete example is listed below.

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# SuperFastPython.com

# example of an unsuccessful exit code message

from time import sleep

from multiprocessing import Process

from sys import exit

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

    # exit unsuccessfully with a message

    exit(‘Something bad happened’)

# protect the entry point

if __name__ == ‘__main__’:

    # configure a new process

    child = Process(target=task)

    # start the child process

    child.start()

    # wait for the child process to finish

    child.join()

    # check the exit code for the child process

    code = child.exitcode

    print(f‘Child exit code: {code}’)

Running the example first creates and starts the child process.

The main process then blocks until the child process terminates.

The child process sleeps for one second, then exits with an exit code of a string message, indicating an unsuccessful exit.

The child process terminates, reports the string message to standard error, then the main process continues on.

The main process then retrieves the exit code from the child process and reports the value.

In this case, we can see that the message was reported automatically, and that the exit code has the value of one, indicating an unsuccessful exit.

Something bad happened

Child exit code: 1

Free Python Multiprocessing Course

Download my multiprocessing API cheat sheet and as a bonus you will get FREE access to my 7-day email course.

Discover how to use the Python multiprocessing module including how to create and start child processes and how to use a mutex locks and semaphores.

Learn more
 

Automatic Exit Codes

This section provides examples of automatically setting an exit code when terminating a process.

Automatic Exit Code On Normal Exit

In this case we can explore the exit code set automatically when a Python process exits normally.

Recall that the exit code is set to zero indicating a successful exit when a Python process exits normally.

We can achieve this by updating the previous example to remove the call to sys.exit() from the task() function executed in a child process.

The updated task() function with this change is listed below.

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

Tying this together, the complete example is listed below.

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# SuperFastPython.com

# example of a normal successful exit for a process

from time import sleep

from multiprocessing import Process

from sys import exit

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

# protect the entry point

if __name__ == ‘__main__’:

    # configure a new process

    child = Process(target=task)

    # start the child process

    child.start()

    # wait for the child process to finish

    child.join()

    # check the exit code for the child process

    code = child.exitcode

    print(f‘Child exit code: {code}’)

Running the example first creates and starts the child process.

The main process then blocks until the child process terminates.

The child process sleeps for one second, then exits normally with no explicit exit code

The child process terminates then the main process continues on. It retrieves the exit code from the child process and reports the value.

In this case, we can see it has the value zero indicating a successful exit was set automatically when the child process exited normally.

Automatic Exit Code On Exception

In this case we can explore the exit code set automatically when a Python process exits with an exception.

Recall that the exit code is set to one indicating an unsuccessful exit when a Python process exits with an exception.

We can achieve this by updating the previous example to raise an exception in the function executed by the child process.

...

# raise an exception

raise Exception(‘Something bad happened’)

The updated task() function with this change is listed below.

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

    # raise an exception

    raise Exception(‘Something bad happened’)

Tying this together, the complete example is listed below.

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# SuperFastPython.com

# example of a unsuccessful exit for exiting with exception

from time import sleep

from multiprocessing import Process

from sys import exit

# function executed in a child process

def task():

    # block for a moment

    sleep(1)

    # raise an exception

    raise Exception(‘Something bad happened’)

# protect the entry point

if __name__ == ‘__main__’:

    # configure a new process

    child = Process(target=task)

    # start the child process

    child.start()

    # wait for the child process to finish

    child.join()

    # check the exit code for the child process

    code = child.exitcode

    print(f‘Child exit code: {code}’)

Running the example first creates and starts the child process.

The main process then blocks until the child process terminates.

The child process sleeps for one second, then exits by raising an exception.

The exception stack trace is reported to standard error, the default behavior for handling an exception in a child process

The child process terminates then the main process continues on. It retrieves the exit code from the child process and reports the value.

In this case, we can see it has the value zero indicating an unsuccessful exit was set automatically when the child process exited with an exception.

Process Process-1:

Traceback (most recent call last):

  …

Exception: Something bad happened

Child exit code: 1

Further Reading

This section provides additional resources that you may find helpful.

Books

  • Python Multiprocessing Jump-Start, Jason Brownlee, 2022 (my book!).
  • Multiprocessing API Interview Questions
  • Multiprocessing Module API Cheat Sheet

I would also recommend specific chapters in the books:

  • Effective Python, Brett Slatkin, 2019.
    • See: Chapter 7: Concurrency and Parallelism
  • High Performance Python, Ian Ozsvald and Micha Gorelick, 2020.
    • See: Chapter 9: The multiprocessing Module
  • Python in a Nutshell, Alex Martelli, et al., 2017.
    • See: Chapter: 14: Threads and Processes

Guides

  • Python Multiprocessing: The Complete Guide

APIs

  • multiprocessing — Process-based parallelism
  • PEP 371 — Addition of the multiprocessing package

    Takeaways

    You now know how to get and set exit codes for processes in Python.

    Do you have any questions?
    Ask your questions in the comments below and I will do my best to answer.

    Photo by David Maginley on Unsplash

    Источник

    I found the issue here

    In file management_activity.py line 119 

            now = self._now()
        end_time = datetime.utcfromtimestamp(now)
        start_time = end_time - timedelta(days=7)

    The problem is that the time of performing all ranges of 

    self._normalize_time_range(start_time, end_time)

    the latest time-range startTime is greater than 7 days

    The workarround here is to set_up a control in portal.py line 126

    --- a/splunk_ta_o365/bin/splunk_ta_o365/common/portal.py
+++ b/splunk_ta_o365/bin/splunk_ta_o365/common/portal.py
@@ -126,6 +126,10 @@ class O365Subscription(O365Portal):
     def list_available_content(self, session, start_time, end_time):
         for _start_time, _end_time in self._normalize_time_range(start_time, end_time):
             items = list()
+            min_start_date = datetime.utcnow() - timedelta(days=7) + timedelta(minutes=1)
+            _start_time = max(min_start_date, _start_time)
+            if _end_time < min_start_date:
+                yield []
             response = self._list_available_content(session, _start_time, _end_time)
             while True:
                 array = response.json()

    I have put 

        datetime.utcnow() - timedelta(days=7) + timedelta(minutes=1)

    To be sure that the API will receive a not outdate startTime a avoid traffic impact

    if _end_time < min_start_date:
    yield []

    Is here to be sure that the script will not query for an invalid range (if endTime is before the limit of 7 days no need no query this range)

    Hope this helps

         _time                                   ContentType    endTime                            startTime
**2019-03-07 11:15:00.105** Audit.Exchange  2019-02-28T12:06:18 **2019-02-28T11:16:00**
2019-03-07 11:14:52.109 Audit.Exchange  2019-02-28T13:06:18 2019-02-28T12:06:18
2019-03-07 11:14:44.943 Audit.Exchange  2019-02-28T14:06:18 2019-02-28T13:06:18
2019-03-07 11:14:39.220 Audit.Exchange  2019-02-28T15:06:18 2019-02-28T14:06:18
2019-03-07 11:14:31.087 Audit.Exchange  2019-02-28T16:06:18 2019-02-28T15:06:18
2019-03-07 11:14:24.550 Audit.Exchange  2019-02-28T17:06:18 2019-02-28T16:06:18
2019-03-07 11:14:23.513 Audit.Exchange  2019-02-28T18:06:18 2019-02-28T17:06:18
2019-03-07 11:14:23.043 Audit.Exchange  2019-02-28T19:06:18 2019-02-28T18:06:18
2019-03-07 11:14:22.062 Audit.Exchange  2019-02-28T20:06:18 2019-02-28T19:06:18
2019-03-07 11:14:20.283 Audit.Exchange  2019-02-28T21:06:18 2019-02-28T20:06:18
2019-03-07 11:14:17.829 Audit.Exchange  2019-02-28T22:06:18 2019-02-28T21:06:18
2019-03-07 11:14:15.291 Audit.Exchange  2019-02-28T23:06:18 2019-02-28T22:06:18
2019-03-07 11:14:13.837 Audit.Exchange  2019-03-01T00:06:18 2019-02-28T23:06:18
2019-03-07 11:14:11.430 Audit.Exchange  2019-03-01T01:06:18 2019-03-01T00:06:18
2019-03-07 11:14:10.963 Audit.Exchange  2019-03-01T02:06:18 2019-03-01T01:06:18
2019-03-07 11:14:09.427 Audit.Exchange  2019-03-01T03:06:18 2019-03-01T02:06:18
2019-03-07 11:14:09.080 Audit.Exchange  2019-03-01T04:06:18 2019-03-01T03:06:18
2019-03-07 11:14:08.340 Audit.Exchange  2019-03-01T05:06:18 2019-03-01T04:06:18
2019-03-07 11:14:06.699 Audit.Exchange  2019-03-01T06:06:18 2019-03-01T05:06:18
2019-03-07 11:14:04.601 Audit.Exchange  2019-03-01T07:06:18 2019-03-01T06:06:18

    Источник

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    kaycube

    312 Views, 0 Replies

    ‎01-10-2019

    01:22 PM

    Maya commandline executable crash with error:255


    Ubuntu 16.04

    Maya 2018

    Tractor 2.2

    Python 2.7

    Hi,

    I have been pulling my hair out for a couple days now trying to figure out how to launch maya from a python script with subprocessing. I need to spawn a new terminal and run a shotgun toolkit executable to launch maya with a specific set of context. When i do run the command, Maya crashes with a error 255 and i am not sure why. I can launch maya just fine directly from the commandline and i can run from commandline the tank maya-2018 command and that works as well. But when i try to run the exact same command through a subprocess maya errors out with a stack trace: strlen error. The same error occurs on pixar tractor renderfarm when try to spool from a script as well. The error doesnt happen running the spool from within maya but from my script. Any ideas on whats happening and how i can fix it? Thanks

    • Batch rendering
    • Linux
    • Maya
    • maya 2018
    • python
    • Ubuntu


    • Back to forum


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    Источник

    Вот код

    import pymysql
pymysql.connect(
    host='localhost',
    port=3306,
    user='root',
    password='iDontWannaSay',
    db='iDontWannaShow',
    charset='utf8'
)

    И ошибка трассировки была:

    data is :::::b'xffx02x00xffx81x15'....##### I was add near line 1279 which is print("data is :::::%s...."%data[i:i+6])
Traceback (most recent call last):
  File "C:Users123Desktoppymysqldebug.py", line 8, in <module>
    charset='utf8'
  File "D:Program Files (x86)PythonPython35libsite-packagespymysql__init__.py", line 90, in Connect
    return Connection(*args, **kwargs)
  File "D:Program Files (x86)PythonPython35libsite-packagespymysqlconnections.py", line 709, in __init__
    self.connect()
  File "D:Program Files (x86)PythonPython35libsite-packagespymysqlconnections.py", line 934, in connect
    self._get_server_information()
  File "D:Program Files (x86)PythonPython35libsite-packagespymysqlconnections.py", line 1279, in _get_server_information
    self.server_charset = charset_by_id(lang).name
  File "D:Program Files (x86)PythonPython35libsite-packagespymysqlcharset.py", line 39, in by_id
    return self._by_id[id]
KeyError: 255

    Похоже, что метод struct.unpack анализирует ‘ xff ‘ до 255 и присваивается self.server_language независимо от того, что передан ненулевой аргумент charset.

    Это проблема версии MySQL? (Версия 8.0.1-dmr)

    3 ответа

    Лучший ответ

    Чтобы расширить приведенный выше только для ссылки ответ, рассмотрите следующие изменения в вашей текущей pymysql установке. В MySQL 8 API-интерфейс mysql-python не распознает возможно более новые наборы символов и, следовательно, поднятый KeyError.

    Для решения найдите сценарий connectors.py в модуле pymysql, найденном в этом каталоге:

    print(pymysql.__file__)

    Резервное копирование оригинального сценария connectors.py . Затем внесите следующие изменения.

    Оригинал (строки 1268-1269) 

    self.server_language = lang
self.server_charset = charset_by_id(lang).name

    Заменить (строки 1268 — 1272) 

    self.server_language = lang
try:
    self.server_charset = charset_by_id(lang).name
except KeyError:
    self.server_charset = None

    Будьте осторожны, чтобы включить отступы в отступ с указанными выше линиями.

    Ссылка

    • Исправление PyMySQL Git # 591


    8

    Parfait
    3 Дек 2017 в 20:07

    А где твоя переменная?

    import pymysql

    |
    v
myVariable = pymysql.connect(
    host='localhost',
    port=3306,
    user='root',
    password='iDontWannaSay',
    db='iDontWannaShow',
    charset='utf8'
)


    0

    Drumsman
    10 Авг 2017 в 18:42

    Источник

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