[PATCH v1 1/2] daemon: telegram: db: Allow the caller to reconnect

[Ammar Faizi <ammarfaizi2@gnuweeb.org>]

The daemon is totally unusable when the MySQL server is restarted. It's
spinning in a loop with the following error:

   mysql.connector.errors.OperationalError: 2013 (HY000): Lost connection to MySQL server during query

When it happens, the only way to fix the situation is: restart the
daemon manually, which is obviously not productive. Create a mechanism
in the class DB to allow the caller to reconnect. This way, the caller
can automatically reconnect without having the user restart the daemon.

Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
---
 daemon/telegram/database/core.py   | 31 +++++++++++++++++++++++++-----
 daemon/telegram/packages/client.py |  8 ++++----
 daemon/tg.py                       |  4 ++--
 3 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/daemon/telegram/database/core.py b/daemon/telegram/database/core.py
index c34d7a8..bc65b54 100644
--- a/daemon/telegram/database/core.py
+++ b/daemon/telegram/database/core.py
@@ -4,17 +4,38 @@
 # Copyright (C) 2022  Ammar Faizi <ammarfaizi2@gnuweeb.org>
 #
 
-
+from mysql import connector
 from .methods import DBMethods
 
 
 class DB(DBMethods):
-	def __init__(self, conn):
-		self.conn = conn
+	def __init__(self, host, user, password, database):
+		self.host = host
+		self.user = user
+		self.password = password
+		self.database = database
+		self.conn = None
+		self.connect()
+
+	#
+	# Allow the caller to reconnect.
+	#
+	def connect(self):
+		if self.conn:
+			self.close()
+
+		self.conn = connector.connect(
+			host=self.host,
+			user=self.user,
+			password=self.password,
+			database=self.database
+		)
 		self.conn.autocommit = True
 		self.cur = self.conn.cursor(buffered=True)
 
-
-	def __del__(self):
+	def close(self):
 		self.cur.close()
 		self.conn.close()
+
+	def __del__(self):
+		self.close()
diff --git a/daemon/telegram/packages/client.py b/daemon/telegram/packages/client.py
index c971ea1..2ee37f6 100644
--- a/daemon/telegram/packages/client.py
+++ b/daemon/telegram/packages/client.py
@@ -15,11 +15,11 @@ from .decorator import handle_flood
 
 
 class DaemonClient(Client):
-	def __init__(self, name: str, api_id: int,
-		api_hash: str, conn, **kwargs):
+	def __init__(self, name: str, api_id: int, api_hash: str, db: DB,
+		     **kwargs):
 		super().__init__(name, api_id,
-				api_hash, **kwargs)
-		self.db = DB(conn)
+				 api_hash, **kwargs)
+		self.db = db
 
 
 	@handle_flood
diff --git a/daemon/tg.py b/daemon/tg.py
index 5f8c21e..e6d5d05 100644
--- a/daemon/tg.py
+++ b/daemon/tg.py
@@ -6,11 +6,11 @@
 
 from apscheduler.schedulers.asyncio import AsyncIOScheduler
 from dotenv import load_dotenv
-from mysql import connector
 from atom import Scraper
 from telegram.packages import DaemonClient
 from telegram.mailer import BotMutexes
 from telegram.mailer import Bot
+from telegram.database import DB
 import os
 
 
@@ -22,7 +22,7 @@ def main():
 		api_id=int(os.getenv("API_ID")),
 		api_hash=os.getenv("API_HASH"),
 		bot_token=os.getenv("BOT_TOKEN"),
-		conn=connector.connect(
+		db=DB(
 			host=os.getenv("DB_HOST"),
 			user=os.getenv("DB_USER"),
 			password=os.getenv("DB_PASS"),
-- 
Ammar Faizi