Putting it all together: a simple example

Here we create a SubprocessTask to reverse the order of the lines in a file, submit the job to a local Client, and then retrieve and view the result.

from crossflow import clients, tasks, filehandling
from pathlib import Path

# Create a short text file:
here = Path('.')
inp_file = here /'input.txt'
with inp_file.open('w') as f:
    for i in range(10):
        f.write('line {}\n'.format(i))

# Create a SubprocessTask that will reverse the lines in a file:
reverser = tasks.SubprocessTask('tail -r input > output')
reverser.set_inputs(['input'])
reverser.set_outputs(['output'])

# Create a local client to run the job, and submit it:
client = clients.Client()
output = client.submit(reverser, inp_file)

# output is a Future; collect its result(), convert this FileHandle object to a file, and list its contents:
output_file = here / 'joined.txt'
output.result().save(output_file)
print(output_file.read_text()) # or: print(output.result().read_text())

line 9
line 8
line 7
line 6
line 5
line 4
line 3
line 2
line 1
line 0