From e677c4115be876f6702caa6c27594e79f6924fe1 Mon Sep 17 00:00:00 2001
From: Andrew Stowell <andrew@digitaladapt.com>
Date: Thu, 7 Sep 2023 09:20:42 +0000
Subject: [PATCH] prune-old-backups rewritten to work with optional command
 line args, and to work with files or folders.

---
 config.example.sh          |  9 +++--
 crons/prune-old-backups.sh | 68 ++++++++++++++++++++++++++++----------
 2 files changed, 56 insertions(+), 21 deletions(-)

diff --git a/config.example.sh b/config.example.sh
index 980f100..3d756bd 100644
--- a/config.example.sh
+++ b/config.example.sh
@@ -15,12 +15,15 @@ STORAGE_ALERT=(["/"]=5)
 
 BACKUP_DIRECTORY="/home/ubuntu/data"
 
-# when set to 0, all backups are kept
-PRUNE_DOWN_TO=0
-
 # the directory with backups to cleanup
 PRUNE_DIRECTORY="/home/ubuntu/data"
 
+# what type of backups to cleanup (what to find) "*.zip" etc, or "<DIR>"
+PRUNE_TYPE="<DIR>"
+
+# when set to 0, all backups are kept
+PRUNE_DOWN_TO=0
+
 SERVER_DOMAIN="localhost"
 
 DISCORD_SERVER_NAME="<YOUR SERVER>"
diff --git a/crons/prune-old-backups.sh b/crons/prune-old-backups.sh
index a690fc0..f0a8664 100755
--- a/crons/prune-old-backups.sh
+++ b/crons/prune-old-backups.sh
@@ -1,31 +1,63 @@
 #!/bin/bash
 
+# prune the directory of matching files or subfolders,
+# until we only have the desired number of backups remaining.
+# assumes backups are named with something like datestamp,
+# as we want to keep the bottom of the file list wheb sorted.
+
+# pulls from config, but can take overrides:
+# prune-old-backups.sh "where-to-look" "what-to-find" "how-many-to-keep"
+
 LOCATION=`dirname "$0"`
 
 source "${LOCATION}/../config.sh"
 
-# TODO: The maximum number of backups to keep (when set to 0, all backups are kept)
-maxNrOfBackups="$PRUNE_DOWN_TO"
+# directory to prune
+pruneDir="$PRUNE_DIRECTORY"
 
-# TODO: The directory where you store the Nextcloud backups
-backupMainDir="$PRUNE_DIRECTORY"
+# what to prune from that directory
+pruneType="$PRUNE_TYPE"
 
-#
-# Delete old backups
-#
-if [ ${maxNrOfBackups} != 0 ]
-then
-    nrOfBackups=$(ls -l ${backupMainDir} | grep -c ^d)
+# how many to keep
+keepCount="$PRUNE_DOWN_TO"
 
-    if [[ ${nrOfBackups} > ${maxNrOfBackups} ]]
-    then
-        echo "Removing old backups..."
-        ls -t ${backupMainDir} | tail -$(( nrOfBackups - maxNrOfBackups )) | while read -r dirToRemove; do
-            echo "${dirToRemove}"
-            rm -r "${backupMainDir}/${dirToRemove:?}"
-            echo "Done"
-            echo
+if [ -n "$1" ]; then
+    pruneDir="$1"    
+fi
+
+if [ -n "$2" ]; then
+    pruneType=""$2
+fi
+
+if [ -n "$3" ]; then
+    keepCount="$3"
+fi
+
+if (( "${keepCount}" > "0" )); then
+    removedSome=0
+
+    # find direct subfolders to remove
+    if [ "${pruneType}" = "<DIR>" ]; then
+        # notice the grep to remove the pruneDir from the results
+        # head given a negative number will stop that much short from the bottom, so we keep those matches
+        find "${pruneDir}" -maxdepth 1 -type d | grep -v "^${pruneDir}$" | sort | head -n "-${keepCount}" | while read -r dirToRemove; do
+            removedSome=1
+            echo "Removing: ${dirToRemove}"
+            rm -r "${dirToRemove}"
         done
+    else
+        # head given a negative number will stop that much short from the bottom, so we keep those matches
+        find "${pruneDir}" -type f -name "${pruneType}" | sort | head -n "-${keepCount}" | while read -r fileToRemove; do
+            removedSome=1
+            echo "Removing: ${fileToRemove}"
+            rm "${fileToRemove}"
+        done
     fi
+
+if [ "${removedSome}" = "0" ]; then
+    echo 'Nothing to do, we do not have too many backups.'
+fi
+else
+    echo 'Nothing to do, you said keep everything.'
 fi