Add trap to gracefully cleanup, add screen session

Dockerfile

@@ -17,7 +17,7 @@ RUN apk add curl openjdk8-jre &&\
 
 # The second stage is the actual container
 FROM openjdk:8
-RUN apt-get update && apt-get install rsync -y
+RUN apt-get update && apt-get install rsync screen -y
 WORKDIR /minecraft
 COPY --from=build /minecraft .
 CMD [ "bash", "start-server.sh" ]

start-server.sh

@@ -1,4 +1,4 @@
-#! /bin/sh
+#! /bin/bash
 #
 # start-server.sh
 # Copyright (C) 2021 Vintage Salt <rehashedsalt@cock.li>
@@ -33,5 +33,10 @@ java -version
 echo "Invoking java with args: $args"
 
 # Start 'er up
-java $args
+cleanup() {
+	screen -p 0 -S minecraft -X stuff save-all^M
+	screen -p 0 -S minecraft -X stuff stop^M
+}
+trap cleanup EXIT
+screen -DmS minecraft java $args