[Unit]
Description=Certificate renewer for %I
After=network-online.target
Documentation=https://smallstep.com/docs/step-ca/certificate-authority-server-production
StartLimitIntervalSec=0

[Service]
Type=oneshot
User=root

Environment=STEPPATH=/etc/step-ca \
            CERT_LOCATION=/etc/step/certs/%i.crt \
            KEY_LOCATION=/etc/step/certs/%i.key

; ExecStartPre checks if the certificate is ready for renewal,
; based on the exit status of the command.
; (In systemd 243 and above, you can use ExecCondition= here.)
ExecStartPre=/usr/bin/env bash -c \
  'step certificate inspect $CERT_LOCATION --format json --roots "$STEPPATH/certs/root_ca.crt" | \
  jq -e "(((.validity.start | fromdate) + \
          ((.validity.end | fromdate) - (.validity.start | fromdate)) * 0.66) \
           - now) <= 0" > /dev/null'

; ExecStart renews the certificate, if ExecStartPre was successful.
ExecStart=/usr/bin/step ca renew --force $CERT_LOCATION $KEY_LOCATION

; Try to reload or restart the systemd service that relies on this cert-renewer
; If the relying service doesn't exist, forge ahead.
ExecStartPost=-systemctl try-reload-or-restart %i

[Install]
WantedBy=multi-user.target