Merge pull request 'feature-42-image-size-optimization-and-uid-gid-selection' (#3) from feature-42 into develop

Reviewed-on: #3

Dockerfile

@@ -15,20 +15,36 @@ RUN mkdir ${DATA_PATH}/logs && \
 # Generate unicode locale so that cyrillic characters display properly
 RUN apt-get update -y && apt-get install -y locales && \
     echo en_US.UTF-8 UTF-8 > /etc/locale.gen && \
-    dpkg-reconfigure --frontend=noninteractive locales
+    dpkg-reconfigure --frontend=noninteractive locales && \
+    rm -Rf var/lib/apt/lists/*
 ENV LANG en_US.UTF-8
 
 
 VOLUME ${DATA_PATH}
 
 
+EXPOSE 25565/tcp
+
+
 ENV MEMORY=1G
 ENV PROXY_SECRET=change_me
 
+
 WORKDIR ${WORKDIR_PATH}/config
 
-EXPOSE 25565/tcp
-
 CMD \
+    # Create and switch to user with desired UID and GID.
+    # All processes that create/change files in ${DATA_PATH}
+    # must be run under this user.
+    groupadd -g ${GID} worker && \
+    useradd -M -g ${GID} -u ${UID} worker && \
+    chmod -R o-rwx ${WORKDIR_PATH} && \
+
+    # Add proxy secret
     sed -i "s/_PROXY_SECRET_/${PROXY_SECRET}/g" settings.yml && \
-    java -Xms${MEMORY} -Xmx${MEMORY} -jar *.jar --nogui
+
+    # Change UID and GID of used files to desired values.
+    chown -R worker:worker ${WORKDIR_PATH} && \
+
+    # Launch
+    su worker -c "java -Xms${MEMORY} -Xmx${MEMORY} -jar *.jar --nogui"