Using the library_setup functionΒΆ

To integrate Photons with an existing script or to control command-line options, use the library_setup function to instantiate Photons.

For example:

from photons_app.executor import library_setup

from photons_messages import DeviceMessages

import asyncio


async def get_label(collector):
    lan_target = collector.resolve_target("lan")
    reference = collector.reference_object("_")

    async for pkt in lan_target.send(DeviceMessages.GetLabel(), reference):
        print(f"{pkt.serial}: {pkt.label}")


if __name__ == "__main__":
    loop = asyncio.new_event_loop()
    collector = library_setup()
    try:
        loop.run_until_complete(get_label(collector))
    finally:
        loop.run_until_complete(collector.stop_photons_app())
        loop.close()

If the script only performs Photons tasks, use the collector to create the asyncio event loop and perform cleanup functions:

from photons_app.executor import library_setup
from photons_messages import DeviceMessages

async def get_label(collector):
    lan_target = collector.resolve_target("lan")
    reference = collector.reference_object("_")

    async for pkt in lan_target.send(DeviceMessages.GetLabel(), reference):
        print(f"{pkt.serial}: {pkt.label}")

if __name__ == "__main__":
    collector = library_setup()
    collector.run_coro_as_main(get_label(collector))

Use argparse to parse command-line arguments:

from photons_app.executor import library_setup
from photons_messages import DeviceMessages

import argparse

async def get_label(collector):
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--target", choices=[collector.configuration["target_register"].targets.keys()]
    )
    parser.add_argument("--reference", default="_")
    args = parser.parse_args()

    lan_target = collector.resolve_target(args.target)
    reference = collector.reference_object(args.reference)

    async for pkt in lan_target.send(DeviceMessages.GetLabel(), reference):
        print(f"{pkt.serial}: {pkt.label}")

if __name__ == "__main__":
    collector = library_setup()
    collector.run_coro_as_main(get_label(collector))

Note

run_coro_as_main is similar to the asyncio.run function in the Python standard library but does extra work to ensure the event loop is shut down cleanly.