[O] Reimplement scheduler so that only one thread is created

src/scheduler.py

@@ -1,91 +1,107 @@
 import difflib
+import time
 from datetime import datetime
 from io import BytesIO
 
-from telegram.ext import Job, CallbackContext, Updater
+from telegram.ext import CallbackContext, Updater
 
 from src.database import Database
 from src.utils import wrap, render, sendRequest
 
 
-class Scheduler:
-    tasks: {str: {str: Job}} = {}
-    cache: {str: {str: str}} = {}
+class CacheEntry:
+    user: str
+    name: str
+    time: float
+    text: str
 
+    def __init__(self, user: str, name: str, time: float, text: str):
+        self.user = user
+        self.name = name
+        self.time = time
+        self.text = text
+
+
+class Scheduler:
+    # storage[user][name] = CacheEntry
+    storage: {str: {str: CacheEntry}} = {}
+
+    # Constructor
     def __init__(self, database: Database, updater: Updater):
         self.database = database
         self.updater = updater
 
-    def create(self, user: str, taskName: str, request):
-        if user not in self.cache:
-            self.cache[user] = {}
+        # Start job
+        self.job = self.updater.job_queue.run_repeating(self.update, interval=5, first=0)
 
-        def task(context: CallbackContext):
-            # Send request
-            text = wrap(sendRequest(request))
+    # Update tasks
+    def update(self, context: CallbackContext):
+        now = time.time()
+        nowText = datetime.now().strftime('%b %d %Y %H-%M-%S')
+
+        # Function to update a single task
+        def updateTask(cache: CacheEntry):
+            request = self.database.reqs[cache.user][cache.name]
+            if now - cache.time < request.get('interval', 120):
+                return
+
+            # Execute request
+            text: str = wrap(sendRequest(request))
 
             # First time http request
-            if taskName not in self.cache[user]:
-                self.cache[user][taskName] = text
+            if cache.text == '':
+                cache.text = text
 
-            # Compare diff
-            else:
-                # Generate diff
-                diffRaw = difflib.unified_diff(self.cache[user][taskName].splitlines(1), text.splitlines(1),
-                                               fromfile='before', tofile='after')
-                diff = ''.join(diffRaw)
-                self.cache[user][taskName] = text
+            # Generate diff
+            diffRaw = difflib.unified_diff(cache.text.splitlines(True), text.splitlines(True), fromfile='before', tofile='after')
+            diff = ''.join(diffRaw)
 
-                if diff != '':
-                    # Render diff
-                    doc = BytesIO(render(diff))
-                    time = datetime.now().strftime('%b %d %Y %H-%M-%S')
-                    fileName = 'diff %s %s.png' % (taskName, time)
-                    caption = '*%s Changed!*' % taskName
+            # Update cache
+            cache.text = text
 
-                    # Send as file
-                    context.bot.send_document(int(user), doc, fileName, caption, parse_mode='markdown')
+            if diff != '':
+                # Render diff
+                doc = BytesIO(render(diff))
+                fileName = 'diff %s %s.png' % (cache.name, nowText)
+                caption = '*%s Changed!*' % cache.name
 
-        return task
+                # Send as file
+                context.bot.send_document(int(user), doc, fileName, caption, parse_mode='markdown')
 
+        # Update all tasks
+        for user in self.storage:
+            for name in self.storage[user]:
+                updateTask(self.storage[user][name])
+
+    # Start a task
     def start(self, user: str, name: str):
         if self.isStarted(user, name):
             return False
 
         request = self.database.reqs[user][name]
-        if user not in self.tasks:
-            self.tasks[user] = {}
+        if user not in self.storage:
+            self.storage[user] = {}
 
-        self.tasks[user][name] = self.updater.job_queue.run_repeating(self.create(user, name, request), interval=request.get('interval', 120), first=0)
-
-        # Keep record
+        # Add task
+        self.storage[user][name] = CacheEntry(user, name, 0, '')
         if not request['enabled']:
             request['enabled'] = True
             self.database.save()
 
         return True
 
+    # Stop a task
     def stop(self, user: str, name: str):
         if not self.isStarted(user, name):
             return False
 
         # Stop and remove task
-        job = self.tasks[user][name]
-        job.enabled = False
-        job.schedule_removal()
-        self.tasks[user].pop(name, None)
+        self.storage[user].pop(name, None)
         self.database.reqs[user][name]['enabled'] = False
         self.database.save()
 
         return True
 
+    # Check if a task is started
     def isStarted(self, user: str, name: str):
-        return user in self.tasks and name in self.tasks[user]
-
-    def updateInterval(self, user: str, name: str):
-        if not self.isStarted(user, name):
-            return False
-
-        self.stop(user, name)
-        self.start(user, name)
-        return True
+        return user in self.storage and name in self.storage[user]