From 3dad914171e151fb3249f8ca4ae12887e8a78b8c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Patrick=20M=C3=BCller?= <patrick@mueller-patrick.tech>
Date: Tue, 20 Apr 2021 09:16:24 +0200
Subject: [PATCH] #2 Only sending telegram message when a state has changed

---
 LastStateCrawler.py | 51 +++++++++++++++++++++++++++++++++++++++++++++
 main.py             | 37 +++++++++++++++++++++++++++++---
 2 files changed, 85 insertions(+), 3 deletions(-)
 create mode 100644 LastStateCrawler.py

diff --git a/LastStateCrawler.py b/LastStateCrawler.py
new file mode 100644
index 0000000..9960881
--- /dev/null
+++ b/LastStateCrawler.py
@@ -0,0 +1,51 @@
+import pymysql
+
+
+def getWebsiteStates(conn: pymysql.Connection) -> dict:
+	# Get latest known states to check against
+	cur = conn.cursor()
+
+	cur.execute("""
+			WITH summary AS (
+				SELECT web.website_id,
+					   web.success,
+					   ROW_NUMBER() OVER(PARTITION BY web.website_id
+											 ORDER BY web.ping_id DESC) AS rk
+				  FROM website_pings web)
+			SELECT s.*
+			FROM summary s
+			WHERE s.rk = 1;
+		""")
+	websiteStates = cur.fetchall()
+	cur.close()
+
+	returnStates = {}
+	for site in websiteStates:
+		returnStates[site[0]] = (site[1] == 1)
+
+	return returnStates
+
+
+def getServerStates(conn: pymysql.Connection) -> dict:
+	# Get latest known states to check against
+	cur = conn.cursor()
+
+	cur.execute("""
+			WITH summary AS (
+				SELECT srv.server_id,
+					   srv.success,
+					   ROW_NUMBER() OVER(PARTITION BY srv.server_id
+											 ORDER BY srv.ping_id DESC) AS rk
+				  FROM server_pings srv)
+			SELECT s.*
+			FROM summary s
+			WHERE s.rk = 1;
+			""")
+	serverStates = cur.fetchall()
+	cur.close()
+
+	returnStates = {}
+	for server in serverStates:
+		returnStates[server[0]] = (server[1] == 1)
+
+	return returnStates
diff --git a/main.py b/main.py
index fbcfbca..ccff7ae 100644
--- a/main.py
+++ b/main.py
@@ -4,6 +4,7 @@ import ServerPingService
 import WebsitePingService
 import SQLConnectionHandler
 import TelegramHandler
+import LastStateCrawler
 
 def runPings():
 	telegram = TelegramHandler.TelegramHandler()
@@ -21,20 +22,37 @@ def runPings():
 	serverPingResults = []
 	websitePingResults = []
 
+	websiteStates = LastStateCrawler.getWebsiteStates(conn)
+	serverStates = LastStateCrawler.getServerStates(conn)
+
 	for server in servers:
 		ping = ServerPingService.ping(server['hostname'])
+		success = False
 		if ping != -1:
+			# Ping successful, save success
+			success = True
 			resTuple = (server['server_id'], True, ping)
 		else:
 			resTuple = (server['server_id'], False, ping)
-			telegram.sendMessage(users[server['admin_id']]['telegram_id'], (
-				'Your server {} ({}) is not reachable at the moment. Maybe give it a check.'
-			).format(server['name'], server['hostname']))
 		serverPingResults.append(resTuple)
 
+		# Send Telegram message if state has changed
+		if success != serverStates[server['server_id']]:
+			# State has changed, send a message
+			if success:
+				telegram.sendMessage(users[server['admin_id']]['telegram_id'], (
+					'Your server {} ({}) is back online again!'
+				).format(server['name'], server['hostname']))
+			else:
+				telegram.sendMessage(users[server['admin_id']]['telegram_id'], (
+					'Your server {} ({}) is not reachable at the moment. Maybe give it a check.'
+				).format(server['name'], server['hostname']))
+
 	for website in websites:
 		statusCode = WebsitePingService.ping(website['url'])
+		success = False
 		if statusCode == 200:
+			success = True
 			resTuple = (website['website_id'], True, statusCode)
 		else:
 			resTuple = (website['website_id'], False, statusCode)
@@ -43,7 +61,20 @@ def runPings():
 			).format(website['name'], website['url'], statusCode))
 		websitePingResults.append(resTuple)
 
+		# Send Telegram message if state has changed
+		if success != websiteStates[website['website_id']]:
+			# State has changed, send a message
+			if success:
+				telegram.sendMessage(users[website['admin_id']]['telegram_id'], (
+					'Your website {} ({}) is back online again!'
+				).format(website['name'], website['url']))
+			else:
+				telegram.sendMessage(users[website['admin_id']]['telegram_id'], (
+					'Your website {} ({}) is not reachable at the moment (Code {}). Maybe give it a check.'
+				).format(website['name'], website['url'], statusCode))
+
 	cur = conn.cursor()
+
 	# Insert server ping results
 	cur.executemany('INSERT INTO server_pings (server_id, success, milliseconds) VALUES (%s, %s, %s)', serverPingResults)