From 0069faa7fd2aa802a00850b77fc50c43ea4a4b6f Mon Sep 17 00:00:00 2001
From: Frederik Ring <frederik.ring@gmail.com>
Date: Thu, 19 Aug 2021 13:41:19 +0200
Subject: [PATCH] allow passing prefix to limit pruning ops

---
 README.md     | 14 ++++++++++++--
 src/backup.sh |  4 ++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 77a9925..5b14b02 100644
--- a/README.md
+++ b/README.md
@@ -51,11 +51,12 @@ AWS_S3_BUCKET_NAME="<xxx>"
 
 # **IMPORTANT, PLEASE READ THIS BEFORE USING THIS FEATURE**:
 # The mechanism used for pruning backups is not very sophisticated
-# and applies its rules to **all files in the target directory**,
+# and applies its rules to **all files in the target directory** by default,
 # which means that if you are storing your backups next to other files,
 # these might become subject to deletion too. When using this option
 # make sure the backup files are stored in a directory used exclusively
-# for storing them or you might lose data.
+# for storing them or to configure BACKUP_PRUNING_PREFIX to limit
+# removal to certain files.
 
 # Define this value to enable automatic pruning of old backups. The value
 # declares the number of days for which a backup is kept.
@@ -71,6 +72,15 @@ AWS_S3_BUCKET_NAME="<xxx>"
 
 # BACKUP_PRUNING_LEEWAY="10m"
 
+# In case your target bucket or directory contains other files than the ones
+# managed by this container, you can limit the scope of rotation by setting
+# a prefix value. This would usually be the non-parametrized part of your
+# BACKUP_FILENAME. E.g. if BACKUP_FILENAME is `db-backup-%Y-%m-%dT%H-%M-%S.tar.gz`,
+# you can set BACKUP_PRUNING_PREFIX to `db-backup-` and make sure
+# unrelated files are not affected.
+
+# BACKUP_PRUNING_PREFIX="backup-"
+
 ########### BACKUP ENCRYPTION
 
 # Backups can be encrypted using gpg in case a passphrase is given
diff --git a/src/backup.sh b/src/backup.sh
index 621d7cf..d68c0ea 100644
--- a/src/backup.sh
+++ b/src/backup.sh
@@ -105,6 +105,10 @@ echo "Will wait for next scheduled backup."
 
 prune () {
   target=$1
+  if [ ! -z "$BACKUP_PRUNING_PREFIX" ]; then
+    target="$target/${BACKUP_PRUNING_PREFIX}"
+  fi
+
   rule_applies_to=$(
     mc rm $MC_GLOBAL_OPTIONS --fake --recursive --force \
       --older-than "${BACKUP_RETENTION_DAYS}d" \