add ONE_SHOT so container exits after run

Dockerfile

@@ -17,6 +17,7 @@ ENV PGID=1000
 ENV TZ=UTC
 ENV GENERATE_DHPARAM=true
 ENV INTERVAL="0 */6 * * *"
+ENV ONE_SHOT=false
 
 # Single domain
 ENV DOMAINS=
@@ -68,6 +69,7 @@ COPY root /
 RUN chmod +x /container-init.sh && \
     chmod +x /certbot-prepare.sh && \
     chmod +x /certbot-renew.sh && \
+    chmod +x /check-one-shot.sh && \
     chown -R ${PUID}:${PGID} /app /config
 
 ENTRYPOINT [ "/init" ]

README.md

@@ -52,6 +52,7 @@ Core options to the container
 |PUID    |int    |1000   |Sets the UID of the user certbot runs under |
 |PGID    |int    |1000   |Sets the GID of the user certbot runs under |
 |TZ      |[List of valid TZs](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List)    |UTC    |Sets the timezone of the container |
+| ONE_SHOT | false | Whether container exits after first run of certbot, or starts cron-based auto-renewal |
 | GENERATE_DHPARAM | true (case-sensitive) | Generate Diffie-Hellman keys in /config/letsencrypt/keys |
 | INTERVAL | 0 */6 * * * | How often certbot attempts to renew the certificate. Cron syntax |
 | CERT_COUNT | 1 | How many certificates certbot will try to issue (more than 1 not yet implemented) |

root/certbot-prepare.sh

@@ -761,9 +761,19 @@ then
     openssl dhparam -out /config/letsencrypt/keys/ssl-dhparams.pem 4096
 fi
 
-echo "$INTERVAL /certbot-renew.sh >> /config/logs/renew.log" > /config/.crontab.txt
+if [ $ONE_SHOT == "true" ]; then
 
-echo ""
+    echo ""
 
-echo "Starting automatic renewal job. Schedule is $INTERVAL"
-crontab /config/.crontab.txt
+    echo "ONE_SHOT is true - exiting container"
+
+elif [ $ONE_SHOT == "false" ]; then
+
+    echo "$INTERVAL /certbot-renew.sh >> /config/logs/renew.log" > /config/.crontab.txt
+
+    echo ""
+
+    echo "Starting automatic renewal job. Schedule is $INTERVAL"
+    crontab /config/.crontab.txt
+
+fi

root/check-one-shot.sh

@@ -0,0 +1,9 @@
+#!/command/with-contenv bash
+# shellcheck shell=bash
+
+if [ $ONE_SHOT == "true" ]; then
+
+    # Cleanly kill container by sending kill signal to supervisor process
+    kill 1
+
+fi

root/container-init.sh

@@ -28,6 +28,7 @@ echo \
 "PUID=${PUID}
 PGID=${PGID}
 TZ=${TZ}
+ONE_SHOT=${ONE_SHOT}
 INTERVAL=${INTERVAL}
 GENERATE_DHPARAM=${GENERATE_DHPARAM}
 CERT_COUNT=${CERT_COUNT}"

root/etc/s6-overlay/s6-rc.d/check-one-shot/type

@@ -0,0 +1 @@
+oneshot

root/etc/s6-overlay/s6-rc.d/check-one-shot/up

@@ -0,0 +1 @@
+exec /check-one-shot.sh