How to Create a Python 3.6 Parallel Timer for Multiple Tasks

Learn how to implement a `parallel repeat timer` in Python 3.6 using threading for efficient task execution without errors.
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Creating a Parallel Timer in Python 3.6 for Multiple Tasks

In the world of programming, timing is crucial, especially when handling operations that need to occur at regular intervals. Python's threading module offers a way to create timers that can repeat tasks in parallel. If you’ve ever wanted to run multiple timers concurrently but hit a roadblock, this guide is for you!

The Problem

You might have tried using Python’s threading.Timer, but encountered issues when executing multiple timers at once. Here’s a common scenario:

You create a timer to execute a function every 10 seconds.

Upon starting the timers for multiple tasks, only one of them seems to activate and repeat correctly.

This results in unintended behavior, such as stack overflow errors or missed executions.

For example, running the following code:

[[See Video to Reveal this Text or Code Snippet]]

Results in:

[[See Video to Reveal this Text or Code Snippet]]

This indicates that only the first timer is functioning, leading to a stack overflow error.

The Solution

The root of the issue is the incorrect way of setting up the threading.Timer. Here’s how to properly create a parallel timer that ensures all tasks run independently and without conflicts:

Step 1: Correct the Timer Initialization

Instead of calling the function directly when creating the timer, you should define it separately to prevent immediate execution. The corrected code should look like this:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Starting the Timers

Now simplify the main logic to start multiple timers:

[[See Video to Reveal this Text or Code Snippet]]

Key Concepts to Remember

Daemon Threads: By setting the timer thread as a daemon (t.daemon = True), the program will exit even if the timers are running, preventing zombies threads.

Avoiding Immediate Call: Make sure to pass the function as a reference (checkMinute) rather than calling it outright (checkMinute(num)), which would execute it immediately.

Expected Output

With this setup, the output will reflect all timers working together as expected:

[[See Video to Reveal this Text or Code Snippet]]

Timers will execute every 10 seconds, printing their respective identifiers in a parallel manner.

Conclusion

By restructuring how you set up and manage your timers with the threading module in Python, you can efficiently achieve parallel execution of multiple tasks. This not only resolves your immediate coding issue but also enhances your overall capability to manage threads and timers in Python.

With this understanding, you can now apply the same principles to more complex problems involving timers and threading. Happy coding!

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