Real examples of working with multithreading in python?

Question

Python

In books, in articles and attached source codes, everything boils down to them, that you need to create a thread and then make a join. Nowhere are normal examples, at least a little closer to real ones, seen.
Links to articles, books, github where you can see all this.
Thanks

Answer 1

I have an online store in Django. He periodically receives from 1C a json file with a catalog of goods and a bunch of jpegs with photos of these goods. The file must be parsed and the data loaded into the database, and for each photo, make 5 thumbnails. Naturally, reading a volumetric image from disk, scaling it 5 times, and writing it back to disk 5 times is much longer than writing data from a dictionary to the database. In addition, there can be up to 200,000 of them. It was reasonable to move the creation of thumbnails into separate threads.
Function executing in a separate thread:

def create_previews(file_path):
    file_name = os.path.basename(file_path)
    gallery_path = os.path.join(settings.MEDIA_ROOT, 'images')
    for size in settings.PREVIEW_SIZES:
        prefix = '%dx%d_' % size
        preview_path = os.path.join(gallery_path, prefix + file_name)
        if not os.path.exists(preview_path):
            try:
                img = Image.open(file_path)
                if (img.size[0] < size[0]) and (img.size[1] < size[1]):
                    continue
                canvas = Image.new("RGB", size, (255,255,255))
                preview = ImageOps.fit(img, size, Image.ANTIALIAS)
                canvas.paste(preview, (0,0))
                canvas.save(preview_path, optimize=True)
            except Exception as e:
                pass

And in the code that parses the json file, for each photo stored in the database:

t = Thread(target=create_previews, args=(image.data.path,))
t.start()

Answer 2

I strongly recommend that you watch these reports (there are many more on YouTube - you have to look) and fill in the gaps in theory - why multithreading may be needed at all and how to prepare it in Python:
once or
twice
I myself dealt with multithreading in Python from David Beasley's book "Python. A detailed guide ." 2010.
The book is in electronic form on torrents and other "pirated" book depositories.
You can search for examples of usage in popular Python projects - if you ask Google for "most popular python projects" - a list of links will open with the most popular projects and some of them can use multithreading.