Exit early if the appliance is set to use gitbackups for repositories but is missing required script to do so

bin/ghe-backup

@@ -81,6 +81,25 @@ if [ "$(ls -il dest1/testfile | awk '{ print $1 }')" != "$(ls -il dest2/testfile
 fi
 rm -rf src dest1 dest2
 
+# if we should use gitbackups to backup repositories
+should_use_gitbackups_for_repositories(){
+  ghe-ssh "$GHE_HOSTNAME" ghe-config --true "app.github.gitbackups"
+}
+
+# check that the appliance supports using gitbackups for repositories
+can_use_gitbackups_for_repositories(){
+  ghe-ssh "$GHE_HOSTNAME" test -e /data/github/current/bin/backup-repositories
+}
+
+# Exit early if the appliance is missing script to backup repositories using gitbackups
+if should_use_gitbackups_for_repositories; then
+  if ! can_use_gitbackups_for_repositories; then
+    echo "Error: Configuration setting 'app.github.gitbackups' is enabled but gitbackups cannot be used to back up repositories via 'ghe-backup'."
+    echo "Disable configuration setting 'app.github.gitbackups' and re-run 'ghe-backup' to use rsync."
+    exit 1
+  fi
+fi
+
 # To prevent multiple backup runs happening at the same time, we create a
 # in-progress file with the timestamp and pid of the backup process,
 # giving us a form of locking.
@@ -197,25 +216,9 @@ ghe-backup-audit-log || failures="$failures audit-log"
 echo "Backing up hookshot logs ..."
 ghe-backup-es-hookshot || failures="$failures hookshot"
 
-# if we should use gitbackups to backup repositories
-should_use_gitbackups_for_repositories(){
-  ghe-ssh "$GHE_HOSTNAME" ghe-config --true "app.github.gitbackups"
-}
-
-# check that the appliance supports using gitbackups for repositories
-can_use_gitbackups_for_repositories(){
-  ghe-ssh "$GHE_HOSTNAME" test -e /data/github/current/bin/backup-repositories
-}
-
-if should_use_gitbackups_for_repositories; then
-  if can_use_gitbackups_for_repositories; then
-    echo "Backing up Git repositories using gitbackups ..."
-    ghe-backup-repositories-gitbackups || failures="$failures repositories"
-  else
-    # we should probably just default to rsync version in this case?
-    echo "Warning: This version of GHES does not support gitbackups for backing up repositories."
-    echo "Disable app.github.gitbackups config setting and rerun to use rsync."
-  fi
+if should_use_gitbackups_for_repositories && can_use_gitbackups_for_repositories; then
+  echo "Backing up Git repositories using gitbackups ..."
+  ghe-backup-repositories-gitbackups || failures="$failures repositories"
 else
   echo "Backing up Git repositories using rsync ..."
   ghe-backup-repositories-rsync || failures="$failures repositories"