Add CONF_FOLDER property

Closes gh-5203

spring-boot-docs/src/main/asciidoc/deployment.adoc

@@ -571,6 +571,9 @@ the default behavior in a script or on the command line:
 |`LOG_FOLDER`
 |The name of the folder to put log files in (`/var/log` by default).
 
+|`CONF_FOLDER`
+|The name of the folder to read .conf files from (same folder as jar-file by default).
+
 |`LOG_FILENAME`
 |The name of the log file in the `LOG_FOLDER` (`<appname>.log` by default).
 

spring-boot-tools/spring-boot-loader-tools/src/main/resources/org/springframework/boot/loader/tools/launch.script

@@ -42,8 +42,12 @@ cd "$WORKING_DIR" || exit 1
 
 # Source any config file
 configfile="$(basename "${jarfile%.*}.conf")"
+
+# Initialize CONF_FOLDER location defaulting to jarfolder
+[[ -z "$CONF_FOLDER" ]] && CONF_FOLDER="${jarfolder}"
+
 # shellcheck source=/dev/null
-[[ -r "${jarfolder}/${configfile}" ]] && source "${jarfolder}/${configfile}"
+[[ -r "${CONF_FOLDER}/${configfile}" ]] && source "${CONF_FOLDER}/${configfile}"
 
 # Initialize PID/LOG locations if they weren't provided by the config file
 [[ -z "$PID_FOLDER" ]] && PID_FOLDER="{{pidFolder:/var/run}}"