File download (Experimental)

In this tutorial we will describe a way to retrieve files produced by Qiskit Functions.

This function provides a way to download files produced by functions during execution. All you need is to call QiskitServerless.download function and pass tar file name to start downloading the file. Or you can list all available files to you by calling QiskitServerless.files.

Limitations:

• only tar and h5 files are supported

• tar or h5 file should be saved in /data directory during your function execution to be visible by .files() method call

• only /data directory is supported, /data/other_folder will not be visible

• as a provider you have access to /function-data, it works in a similar way as the /data folder with the distinction that users don’t have access to it. Only the providers of the specific functions can see files under that path.

⚠ This interface is experimental, therefore it is subjected to breaking changes.

⚠ This provider is set up with default credentials to a test cluster intended to run on your machine. For information on setting up infrastructure on your local machine, check out the guide on local infrastructure setup.

import os
from qiskit_serverless import ServerlessClient, QiskitFunction

serverless = ServerlessClient(
    token=os.environ.get("GATEWAY_TOKEN", "awesome_token"),
    host=os.environ.get("GATEWAY_HOST", "http://localhost:8000"),
    # If you are using the kubernetes approach the URL must be http://localhost
)
serverless

<gateway-client>

Let’s create a Qiskit Function to write tar file into /data folder

function = QiskitFunction(
    title="file-producer", entrypoint="produce_files.py", working_dir="./source_files/"
)

serverless.upload(function)

QiskitFunction(file-producer)

job = serverless.run("file-producer")
job

<Job | 6be3ac4d-b20e-4493-9961-a187847cff49>

job.result()

{'Message': 'my_file.txt archived into my_file.tar'}

Now we can look at files available using files method

available_files = serverless.files()
available_files

['my_file.tar']

And download them if needed using download method

serverless.file_download(available_files[0])

100%|██████████| 201/201 [00:00<00:00, 331kiB/s]

'downloaded_91ea37d9_my_file.tar'