Check directory permission in docker-entrypoint.sh with test -w (#930)

Author: white-gecko

docker-entrypoint.sh

@@ -2,15 +2,12 @@
 
 set -e
 
-# Get UID/GID from volume dir
-VOLUME_UID=$(stat -c '%u' $VOLUME_DIR)
-VOLUME_GID=$(stat -c '%g' $VOLUME_DIR)
-
-MY_UID=$(id -u)
-MY_GID=$(id -g)
-
 # Run as custom user
-if [ "$MY_GID" != "$VOLUME_GID" ] || [ "$MY_UID" != "$VOLUME_UID" ]; then
+if ! [ -w $VOLUME_DIR ]; then
+    # Get UID/GID from volume dir
+    VOLUME_UID=$(stat -c '%u' $VOLUME_DIR)
+    VOLUME_GID=$(stat -c '%g' $VOLUME_DIR)
+
     # create or modify user and group to match expected uid/gid
     groupadd --gid $VOLUME_GID archivist || groupmod -o --gid $VOLUME_GID archivist
     useradd -ms /bin/bash -u $VOLUME_UID -g $VOLUME_GID archivist || usermod -o -u $VOLUME_UID archivist
@@ -36,4 +33,3 @@ else
     # run process directly
     exec $@
 fi
-