There are a number of options. 0.5.0
introduced hooks which are called when certificates are renewed:
You could also inspect the output of of the renew run and use that to determine your action. For example:
OUT=$(/path/to/letsencrypt-auto renew)
if [ $? -eq 0 ]; then
if grep -q "Congratulations!" <<<$OUT; then
# certificates renewed successfully
else
# certificates not due for renewal
fi
else
# error during renewal
fi