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Printing progress bars

Printing progress bars#

Using tqdm progress bars#

Pooch uses tqdm to print a download progress bar. This is turned off by default but can be enabled using progressbar=True in pooch.retrieve:

fname = retrieve(
    url="https://some-data-server.org/a-data-file.nc",
    known_hash="md5:70e2afd3fd7e336ae478b1e740a5f08e",
    progressbar=True,
)

The resulting progress bar will be printed to the standard error stream (STDERR) and should look something like this:

100%|█████████████████████████████████████████| 336/336 [...]

You can also do the same with pooch.Pooch.fetch:

POOCH = pooch.create(
    ...
)

fname = POOCH.fetch(
    "large-data-file.h5",
    progressbar=True,
)

Alternatively, you can pass progressbar=True directly into one of our downloaders:

# Using fetch
fname = POOCH.fetch(
    "large-data-file.h5",
    downloader=pooch.HTTPDownloader(progressbar=True),
)

# Using retrieve
fname = retrieve(
    url="https://some-data-server.org/a-data-file.nc",
    known_hash="md5:70e2afd3fd7e336ae478b1e740a5f08e",
    downloader=pooch.HTTPDownloader(progressbar=True),
)

Note

tqdm is not installed by default with Pooch. You will have to install it separately in order to use this feature.

Using custom progress bars#

Note

At the moment, this feature is only available for pooch.HTTPDownloader.

Alternatively, you can pass an arbitrary object that behaves like a progress that implements the update, reset, and close methods:

  • update should accept a single integer positional argument representing the current completion (in bytes).

  • reset and close do not take any argument beside self.

The object must also have a total attribute that can be set from outside the class. In other words, the custom progress bar needs to behave like a tqdm progress bar.

Here’s a minimal working example of such a custom “progress display” class:

import sys

class MinimalProgressDisplay:
    def __init__(self, total):
        self.count = 0
        self.total = total

    def __repr__(self):
        return str(self.count) + "/" + str(self.total)

    def render(self):
        print(f"\r{self}", file=sys.stderr, end="")

    def update(self, i):
        self.count = i
        self.render()

    def reset(self):
        self.count = 0

    def close(self):
        print("", file=sys.stderr)

An instance of this class can now be passed to an HTTPDownloader as:

# Assuming you have a pooch.Pooch instance setup
POOCH = pooch.create(
    ...
)

minimal_progress = MinimalProgressDisplay(total=None)

fname = POOCH.fetch(
    "large-data-file.h5",
    downloader=pooch.HTTPDownloader(progressbar=minimal_progress),
)
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