Show global header message when bot loses connection with server

discordbot/titanembeds/bot.py

@@ -17,6 +17,9 @@ class Titan(discord.Client):
         self.http.user_agent += ' TitanEmbeds-Bot'
         self.database = DatabaseInterface(self)
         self.command = Commands(self, self.database)
+        
+        self.database_connected = False
+        self.loop.create_task(self.send_webserver_heartbeat())
 
     def _cleanup(self):
         try:
@@ -31,6 +34,14 @@ class Titan(discord.Client):
             gathered.exception()
         except: # Can be ignored
             pass
+    
+    async def send_webserver_heartbeat(self):
+        await self.wait_until_ready()
+        while not self.database_connected:
+            await asyncio.sleep(1) # Wait until db is connected
+        while not self.is_closed:
+            await self.database.send_webserver_heartbeat()
+            await asyncio.sleep(60)
 
     def run(self):
         try:
@@ -57,6 +68,7 @@ class Titan(discord.Client):
 
         try:
             await self.database.connect(config["database-uri"] + "?charset=utf8mb4")
+            self.database_connected = True
         except Exception:
             self.logger.error("Unable to connect to specified database!")
             traceback.print_exc()

discordbot/titanembeds/database/__init__.py

@@ -7,6 +7,7 @@ from sqlalchemy.ext.declarative import declarative_base
 
 import json
 import discord
+import time
 
 Base = declarative_base()
 
@@ -15,6 +16,7 @@ from titanembeds.database.messages import Messages
 from titanembeds.database.guild_members import GuildMembers
 from titanembeds.database.unauthenticated_users import UnauthenticatedUsers
 from titanembeds.database.unauthenticated_bans import UnauthenticatedBans
+from titanembeds.database.keyvalue_properties import KeyValueProperties
 
 class DatabaseInterface(object):
     # Courtesy of https://github.com/SunDwarf/Jokusoramame
@@ -363,3 +365,15 @@ class DatabaseInterface(object):
                 dbuser.revoked = True
                 session.commit()
                 return "Successfully kicked **{}#{}**!".format(dbuser.username, dbuser.discriminator)
+                
+    async def send_webserver_heartbeat(self):
+        async with threadpool():
+            with self.get_session() as session:
+                key = "bot_heartbeat"
+                q = session.query(KeyValueProperties).filter(KeyValueProperties.key == key)
+                if q.count() == 0:
+                    session.add(KeyValueProperties(key=key, value=time.time()))
+                else:
+                    firstobj = q.first()
+                    firstobj.value = time.time()
+                session.commit()

discordbot/titanembeds/database/keyvalue_properties.py

@@ -0,0 +1,17 @@
+from titanembeds.database import db, Base
+import datetime
+
+class KeyValueProperties(Base):
+    __tablename__ = "keyvalue_properties"
+    id = db.Column(db.Integer, primary_key=True)                    # Auto incremented id
+    key = db.Column(db.String(255), nullable=False)                 # Property Key
+    value = db.Column(db.Text())                                    # Property value
+    expiration = db.Column(db.TIMESTAMP)                            # Suggested Expiration for value (None = no expire) in secs
+
+    def __init__(self, key, value, expiration=None):
+        self.key = key
+        self.value = value
+        if expiration:
+            self.expiration = datetime.now() + timedelta(seconds = expiration)
+        else:
+            self.expiration = None