shmcollectbme680fs.rc

#!/bin/rc

# collects data from bme680fs to shared memory created with ramfs
# requirements and set up:
# - set up shmsensors service (/srv/shmsensors) at boot somewhere (/cfg/.../cpustart)
# -- do that with "ramfs -S shmsensors" and dont forget to set permissions "chmod 666 /srv/shmsensors"
# - mount shared memory per process (/mnt/shmsensors) with "mount -c /srv/shmsensors /mnt/shmsensors"
# - (optional) have a script to periodicly save dato from shared memory to disk if desired
# -- (cron e.g.) "3 * * * * local mount -c /srv/shmsensors /mnt/shmsensors && cp /mnt/shmsensors/* /sys/log/"



# set file retention history in seconds (0 for unlimited)
fh=604800

# log file location
lf=/mnt/shmsensors/bme680

# human readable date format (no whitespace)
hdf=YYYY.MM.DD-hh:mm:ss



# only run if shared ramfs is accesible
if (test ! -r /srv/shmsensors) {
	exit
}

# only run sensor is accesible
if (test ! -r /srv/bme680) {
	exit
}

# mount ...
if (test `{ns | grep shmsensors | wc -l} -eq '0') {
	mount -c /srv/shmsensors /mnt/shmsensors
}



# if no data yet in ramfs, copy from storage
if (test ! -r $lf) {
	cp /sys/log/bme680* /mnt/shmsensors
}



# create file with data headder to describe values
if (! test -r $lf.header){
	echo 'timestamp datetime temp(C) hum(%r.H.) pres(hPa) gas(Ohm)' \
	| awk '{print $1"\t"$2"\t"$3"\t"$4"\t"$5"\t"$6}' >>$lf.header
}

# mount sensor if not mounted
if (test ! -r /mnt/bme680/all) {
	mount -b /srv/bme680 /mnt
}

# if mounted collect data and save
if (test -r /mnt/bme680/all) {
	# read sensor data
	bmeraw=`{cat /mnt/bme680/all}

	mdate=`{date -n}
	hdate=`{date -f $hdf $mdate}
	echo $mdate $hdate $bmeraw | awk '{print $1"\t"$2"\t"$4"\t"$6"\t"$8"\t"$10}' >>$lf
}

# prune older data if set
if (test $fh -gt 0) {
	temp=/mnt/shmsensors/bme680-$pid
	
	dn=`{date -n}
	cod=`{echo $dn - $fh | bc}

	cat /mnt/shmsensors/bme680 | awk -v 'cod='$cod -v 'dn='$dn '{if ($1 > cod) print $0;}' > $temp

	mv $temp $lf
}