Throttles vdirsyncer in case of an HTTP 429 response

vdirsyncer-throttle.sh

#!/bin/bash

set -eu
set -o pipefail

cd $(mktemp --directory --suffix '.vdirsyncer')
touch vdir_err

bash_pid=$$

tail -f vdir_err | grep --line-buffered '429 Client Error' | while read line; do
    pkill --signal STOP --parent "${bash_pid}" vdirsyncer
    sleep 300
    pkill --signal CONT --parent "${bash_pid}" vdirsyncer
done &

vdirsyncer sync --max-workers 1 "$@" 2>vdir_err &
vdirsyncer_pid=$!

trap "kill ${vdirsyncer_pid}" SIGINT

wait "${vdirsyncer_pid}"