Reading and Writing Data

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How to Write Files in Beam

Your apps run in containers that are read only.

There are two use-cases for saving files: persistent files, that you want to access between tasks, and temporary files that will be deleted when your container spins down.

1. Persisting Files: write to a volume.
2. Temporary Files: temporary files can be written to the /tmp directory in your Beam container, for example you could save an image to /tmp/myimage.png.

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Reading and Writing to Volumes

You can read and write to your Volume like any ordinary Python file:

from beam import function, Volume


VOLUME_PATH = "./model_weights"


@function(
    volumes=[Volume(name="model-weights", mount_path=VOLUME_PATH)],
)
def access_files():
    # Write files to a volume
    with open(f"{VOLUME_PATH}/somefile.txt", "w") as f:
        f.write("Writing to the volume!")
    # Read files from a volume
    with open(f"{VOLUME_PATH}/somefile.txt", "r") as f:
        f.read()