Add ability to auto restore

Readme.md

@@ -21,6 +21,7 @@ Mount any directories you'd like to back up as a volume and run
 |OPT_ARGUMENTS| |Any additional arguments to provide to the duplicity backup command. These can also be provided as additional arguments via the command line|
 |PASSPHRASE|Correct.Horse.Battery.Staple|Passphrase to use for GPG|
 |PATH_TO_BACKUP|/data|The path to the directory you wish to backup. If you want to backup multiple, see the [tip below](#backing-up-more-than-one-source-directory)|
+|RESTORE_ON_EMPTY_START| |Set this to "true" and if the `$PATH_TO_BACKUP` is empty, it will restore the latest backup. This can be used for auto recovery from lost data|
 |SKIP_ON_START| |Skips backup on start if set to "true"|
 |VERIFY_CRON_SCHEDULE| |If you want to verify your backups on a schedule, provide it here|
 

entrypoint.sh

@@ -16,6 +16,12 @@ if [ -e "$GPG_KEY_ID" ]; then
     export OPT_ARGUMENTS="$OPT_ARGUMENTS --encrypt-sign-key=\"$GPG_KEY_ID\""
 fi
 
+# If set to restore on start, restore if the data volume is empty
+if [ "$RESTORE_ON_EMPTY_START" == "true" -a -z "$(ls -A $PATH_TO_BACKUP)" ]; then
+    /restore.sh
+fi
+
+# Unless explicitly skipping, take a backup on startup
 if [ "$SKIP_ON_START" != "true" ]; then
     /backup.sh
 fi

itest.sh

@@ -19,13 +19,28 @@ echo "Verify backup..."
 echo "Delete test data..."
 rm -fr /data/*
 
+echo "Verify deleted..."
+test -f /data/test.txt && exit 1 || echo "Gone"
+
 echo "Restore backup..."
 /restore.sh
 
 echo "Verify backup..."
 /verify.sh
 
-echo "Verify incorrect passphrase fails..."
+echo "Delete test data again..."
+rm -fr /data/*
+
+echo "Verify deleted..."
+test -f /data/test.txt && exit 1 || echo "Gone"
+
+echo "Simulate a restart with RESTORE_ON_EMPTY_START..."
+RESTORE_ON_EMPTY_START=true /entrypoint.sh
+
+echo "Verify restore happened..."
+test -f /data/test.txt
+
+echo "Verify restore with incorrect passphrase fails..."
 export PASSPHRASE=Incorrect.Mule.Solar.Paperclip
 
 echo "Fail to restore backup..."