drone-plugin-atomic-deploy-dir/mvdir.sh

#!/bin/sh
set -e

if [ -n "$PLUGIN_SOURCE" -a -n "$PLUGIN_TARGET" ]; then
  set "$PLUGIN_SOURCE" "$PLUGIN_TARGET"
fi

if [ ! -d "$1" ]; then
  echo "$1" must be a directory >&2
  exit 1
fi

SOURCE_TMP=`realpath "$1"`
SOURCE_DIR=`dirname "$SOURCE_TMP"`
SOURCE_BASE=`basename "$SOURCE_TMP"`

if [ -f "$2" -a ! -L "$2" ]; then
  echo "$2" must not exist or be a symlink >&2
  exit 2
fi

TARGET_DIR_TMP=`dirname "$2"`
TARGET_DIR=`realpath "$TARGET_DIR_TMP"`
TARGET_BASE=`basename "$2"`

cd "$TARGET_DIR"
DIR=`mktemp -d -p . "$TARGET_BASE".XXXXXX`
mv "$SOURCE_DIR/$SOURCE_BASE" "$DIR"
chmod a+rx "$DIR"
ln -s "$DIR/$SOURCE_BASE" "$DIR.link"
mv -T "$DIR.link" "$TARGET_BASE"
for OTHER in "$TARGET_BASE".*; do
  test "$OTHER" -ef "$DIR" || rm -rf "$OTHER"
done