add check_apt_update

files/nrpe/check_apt_update

@@ -0,0 +1,26 @@
+#!/bin/bash
+#
+# Usage: /usr/lib/nagios/plugins/check_apt_update
+
+# Nagios Exit Codes
+OK=0
+WARNING=1
+CRITICAL=2
+UNKNOWN=3
+
+OUTPUT=$(sudo apt -o APT::Update::Error-On-NoReleaseUrls=true -q -y update 2>&1)
+EXIT_CODE=$?
+
+if [ $EXIT_CODE -eq 0 ] && [[ ! "$OUTPUT" =~ "W:" ]]; then
+    echo "OK - apt update completed successfully."
+    exit $OK
+else
+    CLEAN_OUTPUT=$(echo "$OUTPUT" | grep -E "(E:|W:)" | head -n 1)
+    
+    if [ -z "$CLEAN_OUTPUT" ]; then
+        CLEAN_OUTPUT=$(echo "$OUTPUT" | head -n 2 | tr '\n' ' ')
+    fi
+
+    echo "WARNING - Issue during apt update | ${CLEAN_OUTPUT}"
+    exit $WARNING
+fi