fix(Dockerfile.rootless): revert to default path for app.ini

The current path of the `$GITEA_APP_INI` configuration file makes the
forgejo application reset every time the container is restarted, unless
a specific volume for this file is created. Consider the following:

* This quirk is not documented
* All configuration data resides in `/var/lib/gitea`
* The custom configuration path defaults to `/var/lib/gitea/custom/conf`
  (see `forgejo -h`)
* Containers mounting the volume `-v /foo/bar:/var/lib/gitea` already
  have this file available to modify. Another volume shouldn't be
  required
* Containers using named volumes can use `docker cp` to modify the file
  inside the volume, if desired

For these reasons, it makes more sense to use the default path for
`$GITEA_APP_INI` rather than require users to create a dedicated volume
for the file. Revert it back to its default while maintaining backwards
compatibility (users can update by simply moving the file to the new
path).

Dockerfile.rootless

@@ -100,8 +100,11 @@ ENV GITEA_CUSTOM /var/lib/gitea/custom
 ENV GITEA_TEMP /tmp/gitea
 ENV TMPDIR /tmp/gitea
 
-#TODO add to docs the ability to define the ini to load (useful to test and revert a config)
-ENV GITEA_APP_INI /etc/gitea/app.ini
+# Legacy config file for backwards compatibility
+# TODO: remove on next major version release
+ENV GITEA_APP_INI_LEGACY /etc/gitea/app.ini
+
+ENV GITEA_APP_INI ${GITEA_CUSTOM}/conf/app.ini
 ENV HOME "/var/lib/gitea/git"
 VOLUME ["/var/lib/gitea", "/etc/gitea"]
 WORKDIR /var/lib/gitea

docker/rootless/usr/local/bin/docker-entrypoint.sh

@@ -13,5 +13,10 @@ fi
 if [ $# -gt 0 ]; then
     exec "$@"
 else
+    # TODO: remove on next major version release
+    # Honour legacy config file if existing
+    if [ -f ${GITEA_APP_INI_LEGACY} ]; then
+        GITEA_APP_INI=${GITEA_APP_INI_LEGACY}
+    fi
     exec /usr/local/bin/gitea -c ${GITEA_APP_INI} web
 fi

docker/rootless/usr/local/bin/docker-setup.sh

@@ -11,6 +11,18 @@ mkdir -p ${GITEA_CUSTOM} && chmod 0700 ${GITEA_CUSTOM}
 mkdir -p ${GITEA_TEMP} && chmod 0700 ${GITEA_TEMP}
 if [ ! -w ${GITEA_TEMP} ]; then echo "${GITEA_TEMP} is not writable"; exit 1; fi
 
+# TODO: remove on next major version release
+# Honour legacy config file if existing, but inform the user
+if [ -f ${GITEA_APP_INI_LEGACY} ] && [ ${GITEA_APP_INI} != ${GITEA_APP_INI_LEGACY} ]; then
+    GITEA_APP_INI_DEFAULT=/var/lib/gitea/custom/conf/app.ini
+    echo -e \
+      "\033[33mWARNING\033[0m: detected configuration file in deprecated default path ${GITEA_APP_INI_LEGACY}." \
+      "The new default is ${GITEA_APP_INI_DEFAULT}. To remove this warning, choose one of the options:\n" \
+      "* Move ${GITEA_APP_INI_LEGACY} to ${GITEA_APP_INI_DEFAULT} (or to \$GITEA_APP_INI if you want to override this variable)\n" \
+      "* Explicitly override GITEA_APP_INI=${GITEA_APP_INI_LEGACY} in the container environment"
+    GITEA_APP_INI=${GITEA_APP_INI_LEGACY}
+fi
+
 #Prepare config file
 if [ ! -f ${GITEA_APP_INI} ]; then