Add Purge Threshold

Adds a purge threshold setting. This setting allows the user to
control at what filled percentage the purge activities are run.
This replaces the default, hard coded 95% point.

The purge threshold defaults at the original 95%. I set a minimum
of 20 and max of 99 because those values felt sensible but am open
to changing those based on feedback.

Note: The purge threshold is still active when the keep option is
set. I added a note for this but this still presents some risk
where users who change this while in Keep mode could have their
services shut down earlier than they expect.

scripts/advanced.php

@@ -130,6 +130,13 @@ if(isset($_GET['submit'])) {
     }
   }
 
+  if (isset($_GET["purge_threshold"])) {
+    $purge_threshold = $_GET["purge_threshold"];
+    if (strcmp($purge_threshold, $config['PURGE_THERSHOLD']) !== 0) {
+        $contents = preg_replace("/PURGE_THERSHOLD=.*/", "PURGE_THERSHOLD=$purge_threshold", $contents);
+    }
+}
+
 if (isset($_GET["max_files_species"])) {
     $max_files_species = $_GET["max_files_species"];
     if (strcmp($max_files_species, $config['MAX_FILES_SPECIES']) !== 0) {
@@ -297,6 +304,11 @@ $newconfig = get_config();
       <input name="full_disk" type="radio" id="keep" value="keep" <?php if (strcmp($newconfig['FULL_DISK'], "keep") == 0) { echo "checked"; }?>>Keep</label>
       <p>When the disk becomes full, you can choose to 'purge' old files to make room for new ones or 'keep' your data and stop all services instead.<br>Note: you can exclude specific files from 'purge' on the Recordings page.</p>
       <br>
+      <label for="purge_threshold">Purge Threshold (Disk Used %):</label>
+      <input name="purge_threshold" type="number" style="width:6em;" min="20" max="99" step="1" value="<?php print($newconfig['PURGE_THRESHOLD']);?>"/>
+      </td></tr><tr><td>
+      <p>Defines how full the disk should be before the purge operations occur.<br>Note: This variable is still active if Keep is set. This means that the servies will be stopped at the purge threshold.</p>
+      </td></tr><tr><td>
       <label for="max_files_species">Amount of files to keep for each species :</label>
       <input name="max_files_species" type="number" style="width:6em;" min="0" step="1" value="<?php print($newconfig['MAX_FILES_SPECIES']);?>"/>
       </td></tr><tr><td>

scripts/disk_check.sh

@@ -3,8 +3,9 @@ set -x
 
 source /etc/birdnet/birdnet.conf
 used="$(df -h ${EXTRACTED} | tail -n1 | awk '{print $5}')"
+purge_threshold="${PURGE_THRESHOLD:-95}"
 
-if [ "${used//%}" -ge 95 ]; then
+if [ "${used//%}" -ge "$purge_threshold" ]; then
 
   case $FULL_DISK in
     purge) echo "Removing oldest data"
@@ -34,7 +35,7 @@ if [ "${used//%}" -ge 95 ]; then
   esac
 fi
 sleep 1
-if [ "${used//%}" -ge 95 ]; then
+if [ "${used//%}" -ge "$purge_threshold" ]; then
   case $FULL_DISK in
     purge) echo "Removing more data"
        rm -rfv ${PROCESSED}/*;;

scripts/install_config.sh

@@ -136,6 +136,10 @@ COLOR_SCHEME="light"
 
 FULL_DISK=purge
 
+## PURGE_THRESHOLD can be set to configure at what disk full percentage the
+## purge operations are triggered.
+PURGE_THRESHOLD=95
+
 ## Maximum amount of files to keep for a given specie (0 = keep all)
 ## Files from the last 7 days, and files protected from purge, are not taken into
 ## account in this number

scripts/update_birdnet_snippets.sh

@@ -100,6 +100,10 @@ if ! grep -E '^COLOR_SCHEME=' /etc/birdnet/birdnet.conf &>/dev/null;then
   echo "COLOR_SCHEME=\"light\"" >> /etc/birdnet/birdnet.conf
 fi
 
+if ! grep -E '^PURGE_THRESHOLD=' /etc/birdnet/birdnet.conf &>/dev/null;then
+  echo "PURGE_THRESHOLD=\"95\"" >> /etc/birdnet/birdnet.conf
+fi
+
 if ! grep -E '^MAX_FILES_SPECIES=' /etc/birdnet/birdnet.conf &>/dev/null;then
   echo "MAX_FILES_SPECIES=\"0\"" >> /etc/birdnet/birdnet.conf
 fi