Section 1.1: The Need for Reloading

During the execution of Python scripts, many developers, including myself, have encountered moments where essential details for tracking the progress of a pipeline have been overlooked. This situation is particularly common when training machine learning models. Frequently, we might forget to:

• Log crucial information.
• Display important metrics like accuracy, error rates, and precision.
• Save the model at regular intervals.

I'm sure many of you have faced similar challenges. This issue, however, isn't confined to machine learning; it also arises in other areas such as web scraping, where one might realize after running a script that additional data should have been collected.

When faced with this predicament, the only option often is to halt the execution, incorporate the missing elements, and restart the process. This can be incredibly frustrating, especially if the pipeline has been running for several hours.

But what if there were a solution? Imagine being able to implement changes to a script that's already in motion without losing your progress. This is precisely what I intend to discuss in this blog.

Section 1.2: Understanding Reloading

Reloading is a Python library designed to allow you to refresh a loop or function from its source code before each iteration. This functionality means you can adjust running code and incorporate additional details without compromising any existing progress. Isn’t that amazing?

To install this library, you can use the following command:

pip install reloading

Reloading a Loop

Let’s consider a loop that starts with an initial value and halves it with each iteration. If we overlook printing the iteration number, we may want to amend this later. Without the reloading feature, we would typically need to restart the loop.

However, by wrapping the iterator with the reloading function, you can refresh the loop’s body before each iteration. Here’s how:

from reloading import reload

for i in reload(range(10)):

print(i) # Now you can modify this line during run-time

A demonstration of this functionality is shown below:

Reloading a Function

Just like loops, functions can also be reloaded after each iteration. Consider the function half_value:

To enable reloading for a function, simply decorate it with the reloading decorator. Here’s an example:

from reloading import reload

@reload

def half_value(x):

return x / 2

You can modify the function while it runs, which is demonstrated in the following GIF: