Merge "Don't cache debootstrap rootfs by default"

elements/debootstrap/README.rst

@@ -25,6 +25,11 @@ pass extra arguments to the debootstrap command used to create the
 base filesystem image. If --keyring is is used in `DIB_DEBOOTSTRAP_EXTRA_ARGS`,
 it will override `DIB_APT_KEYRING` if that is used as well.
 
+The `DIB_DEBOOTSTRAP_CACHE` variable can be used to cache the created root
+filesystem. By default this is 0 (disabled) and any other value enables this.
+If run in offline mode then the most recently cached rootfs is used instead of
+being built.
+
 -------------------
 Note on ARM systems
 -------------------

elements/debootstrap/root.d/08-debootstrap

@@ -72,7 +72,9 @@ else
         ${DIB_DEBIAN_DEBOOTSTRAP_SCRIPT:-}"
 
     echo Caching debootstrap result in $DEBOOTSTRAP_TARBALL
+    if [ "${DIB_DEBOOTSTRAP_CACHE:-0}" != "0" ]; then
         sudo tar --numeric-owner -C $TARGET_ROOT -zcf $DEBOOTSTRAP_TARBALL --exclude='./tmp/*' .
+    fi
 fi
 
 sudo rm -f ${TARGET_ROOT}/.extra_settings