docker-adsb-ultrafeeder/rootfs/etc/services.d/autogain/run

#!/usr/bin/with-contenv bash
# shellcheck shell=bash disable=SC2076

# Autogain routine
#
# Relevant env variables:
#   READSB_GAIN: set to "autogain" to enable autogain
#   READSB_AUTOGAIN_INITIAL_INTERVAL: time in seconds to run autogain during initial assessment period; 300 if omitted
#   READSB_AUTOGAIN_SUBSEQUENT_INTERVAL: time in seconds to run autogain during initial assessment period; 86400 (=1 day) if omitted
# Command to restart autogain: docker exec -it tar1090 /usr/local/bin/autogain1090 reset

READSB_AUTOGAIN_INITIAL_INTERVAL="${READSB_AUTOGAIN_INITIAL_INTERVAL:-300}"
READSB_AUTOGAIN_SUBSEQUENT_INTERVAL="${READSB_AUTOGAIN_SUBSEQUENT_INTERVAL:-86400}"
READSB_AUTOGAIN_INITIAL_TIMEPERIOD="${READSB_AUTOGAIN_INITIAL_TIMEPERIOD:-7200}"

if [[ "${READSB_GAIN,,}" != "autogain" ]]; then
    # Autogain is not enabled, so let's do nothing forever
    sleep infinity
fi

if [[ "${READSB_DEVICE_TYPE,,}" != "rtlsdr" ]] || [[ -z "${READSB_RTLSDR_DEVICE}" ]]; then
    echo "[autogain] ERROR: AUTOGAIN enabled but READSB_DEVICE_TYPE is not \"rtlsdr\" or READSB_RTLSDR_DEVICE serial number not defined. Autogain disabled."
    sleep infinity
fi

mkdir -p /var/globe_history/autogain

# Do special things if it's the first time AUTOGAIN is running
if [[ ! -f /var/globe_history/autogain/autogain_initialized ]]; then
    # run autogain every $READSB_AUTOGAIN_INITIAL_INTERVAL secs (default 5 mins) for $READSB_AUTOGAIN_INITIAL_TIMEPERIOD secs (default 2 hours)
    for (( i=0; i<$(( READSB_AUTOGAIN_INITIAL_TIMEPERIOD / READSB_AUTOGAIN_INITIAL_INTERVAL )); i++ ))
    do
        sleep "$READSB_AUTOGAIN_INITIAL_INTERVAL"   # sleep first to give readsb the opportunity to collect some initial data
        /usr/local/bin/autogain1090 2>&1 | mawk -W Interactive '{print "[autogain] " $0}'
    done
    touch /var/globe_history/autogain/autogain_initialized
fi

while true
do
    sleep "$READSB_AUTOGAIN_SUBSEQUENT_INTERVAL"
    /usr/local/bin/autogain1090 2>&1 | mawk -W Interactive '{print "[autogain] " $0}'
done