DBus daemon: Managing requests

[o-alquimista]

I'm using the DBus daemon through gpiocli from a shell script. The script is run by cron once a minute.

From my understanding, we're supposed to make a request and store its name for later reuse.

request=$(gpiocli request --output --chip="$chip" "$line")
# request0
gpiocli set --request="$request" "$line"=active

I can think of two different solutions:

1. Store it in a text file in /var/run
2. Extract it from the output of gpiocli requests, using the chip name and line number

The latter seems neater. Here's how I did it:

gpiocli requests
# request0 (gpiochip0) Offsets: [18]

request=$(gpiocli requests | grep "$chip" | grep "$line")
if [ $? -ne 0 ]; then
    # Make a new request
    gpiocli request --output --chip="$chip" "$line"
else
    # Reuse existing request
    request=$(echo "$request" | awk '{print $1}')
fi

Is this good? Or should I not be afraid of creating files in /var/run?

libgpiod v2.2

[brgl]

Yes, that's why gpiocli requests is there. Instead of parsing its output you may also use gdbus to inspect the properties of the request object directly if your system has it.