Add scripted gluetun VPN port forwarding

- Add compose for gluetun and rtorrent services
- Add runtime configuration options via SETTING_ prefix
- Implement dynamic port discovery in entrypoint script
- Add debug options for troubleshooting

.gitignore

@@ -0,0 +1 @@
+.env

docker-compose.yml

@@ -0,0 +1,33 @@
+volumes:
+  gluetun:
+
+services:
+  gluetun:
+    image: "qmcgaw/gluetun:${GLUETUN_VERSION}"
+    container_name: "${GLUETUN_NAME:-gluetun}"
+    cap_add:
+      - NET_ADMIN
+    devices:
+      - /dev/net/tun:/dev/net/tun
+    volumes:
+      - gluetun:/gluetun
+      - "${GLUETUN_TMP:-./scratch/gluetun}:/tmp/gluetun"
+    environment:
+      - OPENVPN_USER=${VPN_USER}
+      - OPENVPN_PASSWORD=${VPN_PASSWORD}
+      - TZ=America/New_York
+      - VPN_PORT_FORWARDING=${VPN_PORTFORWARD:-off}
+      - VPN_SERVICE_PROVIDER=private internet access
+      - VPN_TYPE=openvpn
+
+  rtorrent:
+    image: ${RTORRENT_IMAGE:-localhost/rtorrent}:${RTORRENT_VERSION:-latest}
+    container_name: "${RTORRENT_NAME:-rtorrent}"
+    network_mode: "service:gluetun"
+    depends_on:
+      - gluetun
+    environment:
+      - DEBUG=${DEBUG:-false}
+      - GLUETUN_FORWARD=${GLUETUN_FORWARD:-false}
+    volumes:
+      - "${GLUETUN_TMP:-./scratch/gluetun}:/tmp/gluetun:ro"

entrypoint.sh

@@ -1,13 +1,29 @@
 #!/bin/bash
 set -eu
 
-# Polling interval
-SLEEP_INTERVAL=${SLEEP_INTERVAL:-2}
-
 # GID/UID
 USER_ID=${GUID:-1000}
 GROUP_ID=${PGID:-1000}
 
+# Polling interval
+SLEEP_INTERVAL=${SLEEP_INTERVAL:-2}
+
+# Gluetun config
+GLUETUN_FORWARD=${GLUETUN_FORWARD:-false}
+GLUETUN_TIMEOUT=${GLUETUN_TIMEOUT:-120}
+GLUETUN_INITIAL_DELAY=${GLUETUN_INITIAL_DELAY:-5}
+
+# rtorrent runtime config
+RTORRENT_RC=${RTORRENT_RC:-/home/rtorrent/.rtorrent.rc}
+RTORRENT_PREFIX=${RTORRENT_PREFIX:-SETTING_}
+
+# Debug
+DEBUG=${DEBUG:-false}
+DEBUG_DIRECT=${DEBUG_DIRECT:-false}
+if [ "$DEBUG" = "true" ]; then
+    set -x
+fi
+
 # Create group/user
 getent group rtorrent >/dev/null || groupadd -g "$GROUP_ID" rtorrent
 id -u rtorrent &>/dev/null || \
@@ -18,13 +34,95 @@ groupmod -o -g "$GROUP_ID" rtorrent
 usermod -o -u "$USER_ID" rtorrent &>/dev/null
 
 # Copy default config
-if [ ! -e /home/rtorrent/.rtorrent.rc ]; then
-    cp /tmp/rtorrent.rc.template /home/rtorrent/.rtorrent.rc
-    chown rtorrent:rtorrent /home/rtorrent/.rtorrent.rc
+if [ ! -e "$RTORRENT_RC" ]; then
+    cp /tmp/rtorrent.rc.template "$RTORRENT_RC"
+    chown rtorrent:rtorrent "$RTORRENT_RC"
+    echo "INFO: Copied template .rtorrent.rc"
+fi
+
+# Optionally set forwarded port from Gluetun
+if [ "$GLUETUN_FORWARD" = "true" ]; then
+
+    # Is the port range already set?
+    if grep -q "^SETTING_network__port_range__set" < <(env); then
+        echo "[ERROR]: GLUETUN_FORWARD and SETTING_network__port_range__set is set"
+        exit 1
+    fi
+
+    # Check if GLUETUN_IP is already set
+    if [ -n "${GLUETUN_IP+x}" ]; then
+        echo "[ERROR]: GLUETUN_IP is already set"
+        exit 1
+    fi
+
+    sleep "$GLUETUN_INITIAL_DELAY"
+    GLUETUN_START_TIME="$(date +%s)"
+
+    while true; do
+        GLUETUN_CURRENT_TIME="$(date +%s)"
+        GLUETUN_DIFF_TIME="$((GLUETUN_CURRENT_TIME - GLUETUN_START_TIME))"
+
+        # Timeout check
+        if [ "$GLUETUN_DIFF_TIME" -ge "$GLUETUN_TIMEOUT" ]; then
+            echo "[ERROR]: Waited $DIFF_TIME/$GLUETUN_TIMEOUT seconds for Gluetun values"
+            exit 1
+        fi
+
+        # Check forwarded_port and IP
+        if [ -f /tmp/gluetun/forwarded_port ]; then
+            FORWARDED_PORT="$(cat /tmp/gluetun/forwarded_port)"
+            if [ -n "$FORWARDED_PORT" ] && [ "$FORWARDED_PORT" != "0" ]; then
+                if [ -f /tmp/gluetun/ip ]; then
+                    GLUETUN_IP=$(cat /tmp/gluetun/ip)
+                    if [ -n "$GLUETUN_IP" ] && [ "$GLUETUN_IP" != "" ]; then
+                        break
+                    fi
+                fi
+            fi
+        fi
+
+        # Waiting
+        echo "Waiting ($GLUETUN_DIFF_TIME/$GLUETUN_TIMEOUT seconds) for Gluetun values"
+        sleep 5
+    done
+
+    # Set range
+    # shellcheck disable=SC2034
+    export SETTING_network__port_range__set="${FORWARDED_PORT}-${FORWARDED_PORT}"
+fi
+
+# Replace key/values
+while IFS='=' read -r ENVVAR VALUE; do
+    if [[ $ENVVAR == ${RTORRENT_PREFIX}* ]]; then
+        KEY="${ENVVAR#"$RTORRENT_PREFIX"}"
+        KEY="${KEY//__/.}"
+        if ! grep -q "^${KEY}" "$RTORRENT_RC"; then
+            echo "[WARN]: \"$KEY\" does not exist in $RTORRENT_RC and was not updated"
+        else
+            if [ "$DEBUG" = "true" ]; then
+                echo "[DEBUG] Updating \"$KEY\" to \"$VALUE\""
+            fi
+            sed -i "s|^${KEY}.*|${KEY} = ${VALUE}|" "$RTORRENT_RC"
+        fi
+    else
+        if [ "$DEBUG" = "true" ]; then
+            echo "[DEBUG] \"$ENVVAR\" doesn't have the prefix \"$RTORRENT_PREFIX\""
+        fi
+    fi
+done < <(env)
+
+# See final config if DEBUG
+if [ "$DEBUG" = "true" ]; then
+    cat "$RTORRENT_RC"
 fi
 
 # Start rtorrent in a detached screen session
-su - rtorrent -c "screen -dmS rtorrent rtorrent" &
+# NOTE: Running without a screen isn't supported but might output config errors
+if [ ! "$DEBUG_DIRECT" = "true" ]; then
+    su - rtorrent -c "screen -dmS rtorrent rtorrent" &
+else
+    su - rtorrent -c "rtorrent" &
+fi
 
 # Wait for the su process to finish
 wait $!
@@ -36,5 +134,6 @@ RTORRENT_PID="$(pgrep -f "^rtorrent$")"
 trap 'su - rtorrent -c "kill -15 $RTORRENT_PID"' SIGTERM SIGINT
 
 # Wait for PID
+[ "$DEBUG" = "true" ] && set +x
 while kill -0 "$RTORRENT_PID" 2>/dev/null; do sleep "$SLEEP_INTERVAL"; done
 exit 0

scratch/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore