Set configuration parameters by variables

Dockerfile

@@ -20,6 +20,7 @@ COPY --from=pidproxy /usr/bin/pidproxy /usr/bin/pidproxy
 RUN apk --no-cache add vsftpd tini
 
 COPY start_vsftpd.sh /bin/start_vsftpd.sh
+COPY update_conf.sh /bin/update_conf.sh
 COPY vsftpd.conf /etc/vsftpd/vsftpd.conf
 
 EXPOSE 21 21000-21010

README.md

@@ -20,6 +20,7 @@ Environment variables:
 - `ADDRESS` - external address to which clients can connect for passive ports (optional, should resolve to ftp server ip address)
 - `MIN_PORT` - minimum port number to be used for passive connections (optional, default `21000`)
 - `MAX_PORT` - maximum port number to be used for passive connections (optional, default `21010`)
+- `CONF_<PARM>` - custom parameter in configuration file, <PARM> may be UPPER or lower case
 
 ## USERS examples
 
@@ -29,6 +30,17 @@ Environment variables:
 - `user|password||10000`
 - `user|password||10000|82` : add to an existing group (www-data)
 
+## CONF examples
+
+- `CONF_FTPD_BANNER`: `My ftps server`
+- `CONF_CHROOT_LOCAL_USER`: `YES`
+- `CONF_chroot_list_enable`: `YES`
+- `CONF_allow_writeable_chroot`: `YES`
+- `CONF_chroot_list_file`: `/etc/vsftpd.chroot_list`
+- `CONF_max_login_fails`: `3`
+- `CONF_max_per_ip`: `3`
+- `CONF_max_clients`: `10`
+
 ## FTPS (File Transfer Protocol + SSL) Example
 
 Issue free Let's Encrypt certificate and use it with `alpine-ftp-server`.
@@ -61,13 +73,19 @@ docker run -d \
 - Do not forget to renew certificate in 3 month with `certbot renew` command.
 
 ## Via docker-compose
+
 ```
 alpine-ftp-server:
   image: delfer/alpine-ftp-server
   ports:
     - "21:21"
     - 21000-21010:21000-21010
   environment:
+    - CONF_FTPD_BANNER="My ftps server"
+    - CONF_CHROOT_LOCAL_USER=YES
+    - CONF_chroot_list_enable=YES
+    - CONF_allow_writeable_chroot=YES
+    - CONF_chroot_list_file=/etc/vsftpd.chroot_list
     - USERS="one|1234"
     - ADDRESS=ftp.site.domain
   volumes:

start_vsftpd.sh

@@ -76,6 +76,8 @@ fi
 if [ ! -z "$1" ]; then
   exec "$@"
 else
+  #Update configuration file
+  /bin/update_conf.sh
   vsftpd -opasv_min_port=$MIN_PORT -opasv_max_port=$MAX_PORT $ADDR_OPT $TLS_OPT /etc/vsftpd/vsftpd.conf
   [ -d /var/run/vsftpd ] || mkdir /var/run/vsftpd
   pgrep vsftpd | tail -n 1 > /var/run/vsftpd/vsftpd.pid

update_conf.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+readonly CONF_FILE_PATH="/etc/vsftpd/vsftpd.conf"
+
+env | grep -E '^CONF_' | grep -Ev '^CONF_FILE_PATH=' | while IFS== read parm value ; do
+  parm="${parm#CONF_*}" ;
+  parm=`echo "${parm}" | tr 'A-Z' 'a-z'`
+  echo "Setting parm ${parm} to ${value}"
+  if ( grep -qE "^#?${parm}=" ${CONF_FILE_PATH} ) ; then
+    sed -i "s;^#\?${parm}=.*;${parm}=${value};" "${CONF_FILE_PATH}"
+  else
+    sed -i "$ a\\#\n# Parameter based on environment variable\n${parm}=${value}" "${CONF_FILE_PATH}"
+  fi
+done