Add fifo

myproject/settings.py

@@ -43,11 +43,14 @@ INSTALLED_APPS = [
     'channels', # Servidor de WebSockets
 ]
 
+REDIS_HOST = "redis"
+REDIS_PORT = 6379
+
 CHANNEL_LAYERS = {
     "default": {
         "BACKEND": "channels_redis.core.RedisChannelLayer",
         "CONFIG": {
-            "hosts": [("redis", 6379)],
+            "hosts": [(REDIS_HOST, REDIS_PORT)],
         },
     },
 }
@@ -61,8 +64,8 @@ HUEY = {
     'utc': False,
     'blocking': True,
     'connection': {
-        'host': 'redis',
-        'port': 6379,
+        'host': REDIS_HOST,
+        'port': REDIS_PORT,
         'db': 0,
         'connection_pool': None,
         'read_timeout': 1,

waiting_room/consumers.py

@@ -1,14 +1,19 @@
 import json
+import redis
+from django.conf import settings
 from channels.generic.websocket import WebsocketConsumer
 from asgiref.sync import async_to_sync
-from waiting_room.tasks import calculate_min_distance
+from waiting_room.tasks import calculate_min_distance, run_tasks_from_queue, render_location_in_the_queue, notify_of_new_position
 
 class MyConsumer(WebsocketConsumer):
 
+    redis_conn = redis.StrictRedis(host=settings.REDIS_HOST, port=settings.REDIS_PORT, db=0)
+
     def connect(self):
         self.room_group_name = self.scope["url_route"]["kwargs"]["room_name"]
         async_to_sync(self.channel_layer.group_add)(self.room_group_name, self.channel_name)
         self.accept()
+        notify_of_new_position()
 
     def disconnect(self, close_code):
         async_to_sync(self.channel_layer.group_discard)(self.room_group_name, self.channel_name)
@@ -16,11 +21,15 @@ class MyConsumer(WebsocketConsumer):
 
     def receive(self, text_data):
         json_data = json.loads(text_data)
-        # Echo
-        self.send(text_data=text_data)
         # Run task
         if json_data['task'] == 'calculate':
-            calculate_min_distance(self.room_group_name)
+            # Check if the new task is already in the queue
+            if self.redis_conn.lrange('enqueue', 0, -1).count(self.room_group_name.encode()) == 0:
+                # Add the task to the queue
+                self.redis_conn.rpush('enqueue', self.room_group_name)
+                notify_of_new_position()
+                # Send accurate location in the queue
+                run_tasks_from_queue()
 
     def channel_message(self, event):
         message = event['message']

waiting_room/tasks.py

@@ -1,4 +1,6 @@
-from huey.contrib.djhuey import task
+from django.conf import settings
+import redis
+from huey.contrib.djhuey import task, lock_task
 import operator
 from django.template.loader import render_to_string
 from itertools import permutations
@@ -8,6 +10,7 @@ from math import factorial
 from channels.layers import get_channel_layer
 from asgiref.sync import async_to_sync
 
+
 def render_progress_bar(group_name, progress, result=None):
     channel_layer = get_channel_layer()
     async_to_sync(channel_layer.group_send)(
@@ -21,6 +24,18 @@ def render_progress_bar(group_name, progress, result=None):
         }
     )
 
+def render_location_in_the_queue(group_name, location):
+    channel_layer = get_channel_layer()
+    async_to_sync(channel_layer.group_send)(
+        group_name,
+        {
+            'type': 'channel_message',
+            'message': render_to_string('components/tasks/location.html', {
+                'location': location,
+            }),
+        }
+    )
+
 @task()
 def calculate_min_distance(group_name):
     # Distance matrix between cities
@@ -72,3 +87,25 @@ def calculate_min_distance(group_name):
         return shortest_route
 
     return calculate_shortest_route(distances)
+
+@task()
+@lock_task('run-queue-lock')
+def run_tasks_from_queue():
+    notify_of_new_position()
+    # Get the first task from the queue
+    redis_conn = redis.StrictRedis(host=settings.REDIS_HOST, port=settings.REDIS_PORT, db=0)
+    task = redis_conn.lindex('enqueue', 0)
+    if task:
+        # Run task
+        r = calculate_min_distance(task.decode('utf-8'))
+        # Wait for task to finish
+        r(blocking=True)
+        # Run the next task
+        redis_conn.lpop('enqueue')
+        run_tasks_from_queue()
+
+@task()
+def notify_of_new_position():
+    redis_conn = redis.StrictRedis(host=settings.REDIS_HOST, port=settings.REDIS_PORT, db=0)
+    for index, group_name in enumerate(redis_conn.lrange('enqueue', 0, -1)):
+        render_location_in_the_queue(group_name.decode('utf-8'), index )

waiting_room/templates/components/tasks/layout.html

@@ -9,6 +9,7 @@
 	background: lightgray;
 	">
     {% include 'components/tasks/update.html' %}
+    {% include 'components/tasks/location.html' %}
 </section>
 <script>
  document.querySelector('#component-notification').setAttribute('ws-connect', '/ws/' + localStorage.getItem('userId') + '/');

waiting_room/templates/components/tasks/location.html

@@ -0,0 +1,5 @@
+<div id="component-notification__location">
+    {% if location > 0 %}
+    <p>You have {{ location }} persons in front of you.</p>
+    {% endif %}
+</div>