mc: apply INIT/MAX RAM settings into FTB local settings file

fixes #222

minecraft-server/examples/docker-compose-ftb.yml

@@ -0,0 +1,16 @@
+version: '3.2'
+
+services:
+  mc:
+    image: itzg/minecraft-server
+    environment:
+      EULA: "true"
+      TYPE: FTB
+      FTB_SERVER_MOD: https://www.feed-the-beast.com/projects/ftb-presents-skyfactory-3/files/2481284
+    ports:
+      - 25565:25565
+    volumes:
+      - mc-ftb:/data
+
+volumes:
+  mc-ftb:

minecraft-server/start-minecraftFinalSetup

@@ -73,8 +73,7 @@ if [[ ${GUI} = false || ${GUI} = FALSE ]]; then
 fi
 
 # put these prior JVM_OPTS at the end to give any memory settings there higher precedence
-echo "Setting initial memory to ${INIT_MEMORY:-${MEMORY}} and max to ${MAX_MEMORY:-${MEMORY}}"
-JVM_OPTS="-Xms${INIT_MEMORY:-${MEMORY}} -Xmx${MAX_MEMORY:-${MEMORY}} ${JVM_OPTS}"
+echo "Setting initial memory to ${INIT_MEMORY:=${MEMORY}} and max to ${MAX_MEMORY:=${MEMORY}}"
 
 if [[ ${TYPE} == "FEED-THE-BEAST" ]]; then
     if [ ! -e ${FTB_DIR}/ops.json -a -e /data/ops.txt ]; then
@@ -89,6 +88,11 @@ if [[ ${TYPE} == "FEED-THE-BEAST" ]]; then
       cp -f /data/eula.txt ${FTB_DIR}/
     fi
 
+    cat > ${FTB_DIR}/settings-local.sh <<EOF
+export MIN_RAM="${INIT_MEMORY}"
+export MAX_RAM="${MAX_MEMORY}"
+EOF
+
     cd ${FTB_DIR}
     echo "Running FTB server modpack start ..."
     exec mc-server-runner ${FTB_SERVER_START}
@@ -98,5 +102,6 @@ else
     bootstrapArgs="--bootstrap /data/bootstrap.txt"
   fi
 
+  JVM_OPTS="-Xms${INIT_MEMORY} -Xmx${MAX_MEMORY} ${JVM_OPTS}"
   exec mc-server-runner ${bootstrapArgs} java $JVM_XX_OPTS $JVM_OPTS -jar $SERVER "$@" $EXTRA_ARGS
 fi