matrix-monitor.sh

#!/bin/sh

# matrix-monitor.sh: a simple shell script to monitor service availability and report to a Matrix channel.
# Requirements:
# - matrix-commander (set up with --login to the room that should be used)
# - curl
# Usage: check my-service "$(curl my-service.example.org)" "<h1>Hello World</h1>" "My service unexpectedly doesn't say hello to the world."

TRIES=3
CHECK_ONLINE=1
I18N_CHECK_FAILED="Check fehlgeschlagen:"
I18N_CHECK_SUCCEEDED="Fehler behoben:"
I18N_EXPECTED="Erwartete Ausgabe:"

check() {
	id="$1"; actual="$2"; expected="$3"; message="$4"
	countfile="matrix-monitor-$id.count"; restorefile="matrix-monitor-$id.restored"
	if [ "$actual" != "$expected" ]; then
		# Check failed $n times
		n=$(($(cat "$countfile" 2>/dev/null) + 1))
		echo "$id: $message ($n/$TRIES)"

		if [ $n -eq $TRIES ]; then
			# Count is exactly $TRIES, so we need to send a message that it failed!
			msg="<details>"
			msg="$msg<summary>🔴 <strong>$I18N_CHECK_FAILED</strong> <em>$message</em></summary>"
			msg="$msg<div><pre><code>$actual</code></pre></div>"
			msg="$msg<div>$I18N_EXPECTED</div><div><pre><code>$expected</code></pre></div>"
			msg="$msg</details>"
			matrix-commander --html -m "$msg"
		fi
		
		# Update countfile
		echo "$n" > "$countfile"
		rm -f "$restorefile"
		
		# Fail for additional tests
		return 1
	else
		# Check succeeded
		
		if [ -f "$countfile" ]; then
			# Countfile still exists, wait until another successful check.
			echo "$id: ok (just restored, waiting for a second successful check)"
			touch "$restorefile"
			rm -f "$countfile"
		elif [ -f "$restorefile" ]; then
			echo "$id: ok (just restored)"
			# Restorefile exists, send a message that the service is back up.
			msg="✅ <strong>$I18N_CHECK_SUCCEEDED</strong> <em>$message</em>"
			matrix-commander --html -m "$msg"
			rm -f "$restorefile"
		else
			echo "$id: ok"
		fi
	fi
}

if [ -n "$CHECK_ONLINE" ]; then
	# Check if internet connection is available at all, otherwise just quit.
	[ "$(curl -so /dev/null -w "%{http_code}" http://detectportal.firefox.com/canonical.html)" = "200" ] || \
	[ "$(curl -so /dev/null -w "%{http_code}" http://www.msftconnecttest.com/connecttest.txt)" = "200" ] || \
	[ "$(curl -so /dev/null -w "%{http_code}" http://clients3.google.com/generate_204)" = "204" ] || \
	exit 1  # We are really offline!
fi

########################################################################################################################

# Test if Uptime Kuma is working
actual=$(curl -s https://mailbox.org/.well-known/security.txt 2>&1 | grep '^Contact:')
expected=$(printf 'Contact: mailto:security@heinlein-support.de\n')
message="Statusseite nicht erreichbar oder unerwartete Antwort!"
check "statuspage" "$actual" "$expected" "$message"

# Test if port 25 is working
actual=$(printf 'QUIT\r\n' | timeout 10 nc smtp.mailbox.org 25 2>&1 | sed 's/smtp[0-9]*\.mailbox\.org/smtp.mailbox.org/')
expected=$(printf '220 smtp.mailbox.org ESMTP Postfix\r\n221 2.0.0 Bye\r\n')
message="SMTP-Server nicht erreichbar oder unerwartete Antwort!"
check "smtp-handshake" "$actual" "$expected" "$message"

if [ $? -eq 0 ]; then
# Only test SMTP certificate if port 25 is working already
actual=$(timeout 10 openssl s_client -showcerts -servername smtp.mailbox.org -connect smtp.mailbox.org:465 </dev/null 2>&1 | grep '^Verification')
expected=$(printf 'Verification: OK\n')
message="SMTP-Zertifikat ungültig oder keine Verbindung möglich!"
check "smtp-certificate" "$actual" "$expected" "$message"
fi