Cache

.github/workflows/main_restaurantreview.yml

@@ -0,0 +1,63 @@
+# Docs for the Azure Web Apps Deploy action: https://github.com/Azure/webapps-deploy
+# More GitHub Actions for Azure: https://github.com/Azure/actions
+# More info on Python, GitHub Actions, and Azure App Service: https://aka.ms/python-webapps-actions
+
+name: Build and deploy Python app to Azure Web App - restaurantReview
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set up Python version
+        uses: actions/setup-python@v1
+        with:
+          python-version: '3.11'
+
+      - name: Create and start virtual environment
+        run: |
+          python -m venv venv
+          source venv/bin/activate
+
+      - name: Install dependencies
+        run: pip install -r requirements.txt
+
+      # Optional: Add step to run tests here (PyTest, Django test suites, etc.)
+
+      - name: Upload artifact for deployment jobs
+        uses: actions/upload-artifact@v2
+        with:
+          name: python-app
+          path: |
+            . 
+            !venv/
+
+  deploy:
+    runs-on: ubuntu-latest
+    needs: build
+    environment:
+      name: 'Production'
+      url: ${{ steps.deploy-to-webapp.outputs.webapp-url }}
+
+    steps:
+      - name: Download artifact from build job
+        uses: actions/download-artifact@v2
+        with:
+          name: python-app
+          path: .
+
+      - name: 'Deploy to Azure Web App'
+        uses: azure/webapps-deploy@v2
+        id: deploy-to-webapp
+        with:
+          app-name: 'restaurantReview'
+          slot-name: 'Production'
+          publish-profile: ${{ secrets.AZUREAPPSERVICE_PUBLISHPROFILE_0EB1DB70D6D34D01BE7BA033F7890571 }}

README.md

@@ -2,6 +2,13 @@
 
 This is a Python web app using the Django framework and the Azure Database for PostgreSQL relational database service. The Django app is hosted in a fully managed Azure App Service. This app is designed to be be run locally and then deployed to Azure. You can either deploy this project by following the tutorial [*Deploy a Python (Django or Flask) web app with PostgreSQL in Azure*](https://docs.microsoft.com/azure/app-service/tutorial-python-postgresql-app) or by using the [Azure Developer CLI (azd)](https://learn.microsoft.com/azure/developer/azure-developer-cli/overview) according to the instructions below.
 
+## The Cache branch
+The Cache branch in the repository contains sample code to save web response out and user session data in a Redis Cache. For web response caching, if a user clicks into the detailed view of a resturant, the details page will be cached for 60 seconds. This increases the application performance by saving server resource and reducing dependency calls into the PostgreSQL. For user session data such as last viewed restaurant, saving in Redis Cache improves consistency and resiliency comparing with in-memory.
+Files changed in the Cache branch:
+* ./azureproject/production.py and settings.py - added cache and session middlewares
+* ./restaurant_review/views.py - added @cache_page tag and session data "lastViewedRestaurant" 
+* ./restaurant_review/templates/restaurant_review/index.html - added display for 'LastViewedRestaurant'
+
 ## Requirements
 
 The [requirements.txt](./requirements.txt) has the following packages:

azureproject/production.py

@@ -22,6 +22,7 @@
     'django.middleware.clickjacking.XFrameOptionsMiddleware',
 ]
 
+SESSION_ENGINE = "django.contrib.sessions.backends.cache"
 STATICFILES_STORAGE = 'whitenoise.storage.CompressedManifestStaticFilesStorage'
 STATIC_ROOT = os.path.join(BASE_DIR, 'staticfiles')
 
@@ -38,3 +39,15 @@
         'PASSWORD': conn_str_params['password'],
     }
 }
+
+CACHES = {
+        "default": {  
+            "BACKEND": "django_redis.cache.RedisCache",
+            "LOCATION": os.environ.get('CACHELOCATION'),
+            "OPTIONS": {
+                "CLIENT_CLASS": "django_redis.client.DefaultClient",
+                "COMPRESSOR": "django_redis.compressors.zlib.ZlibCompressor",
+                'PASSWORD': os.environ.get('CACHEKEY')
+            },
+        }
+    }

azureproject/settings.py

@@ -53,6 +53,7 @@
     'django.middleware.clickjacking.XFrameOptionsMiddleware',
 ]
 
+SESSION_ENGINE = "django.contrib.sessions.backends.cache"
 ROOT_URLCONF = 'azureproject.urls'
 
 TEMPLATES = [
@@ -119,6 +120,16 @@
     },
 ]
 
+CACHES = {
+        "default": {  
+            "BACKEND": "django_redis.cache.RedisCache",
+            "LOCATION": os.environ.get('CACHELOCATION'),
+            "OPTIONS": {
+                "CLIENT_CLASS": "django_redis.client.DefaultClient",
+                'PASSWORD': os.environ.get('CACHEKEY')
+            },
+        }
+    }
 
 # Internationalization
 # https://docs.djangoproject.com/en/4.0/topics/i18n/

infra/resources.bicep

@@ -10,8 +10,16 @@ param secretKey string
 var prefix = '${name}-${resourceToken}'
 
 var pgServerName = '${prefix}-postgres-server'
+//added for Redis Cache
+var cacheServerName = '${prefix}-redisCache'
 var databaseSubnetName = 'database-subnet'
 var webappSubnetName = 'webapp-subnet'
+//added for Redis Cache
+var cacheSubnetName = 'cache-subnet'
+//added for Redis Cache
+var cachePrivateEndpointName = 'cache-privateEndpoint'
+//added for Redis Cache
+var cachePvtEndpointDnsGroupName = 'cacheDnsGroup'
 
 resource virtualNetwork 'Microsoft.Network/virtualNetworks@2019-11-01' = {
   name: '${prefix}-vnet'
@@ -52,6 +60,12 @@ resource virtualNetwork 'Microsoft.Network/virtualNetworks@2019-11-01' = {
           ]
         }
       }
+      {
+        name: cacheSubnetName
+        properties:{
+          addressPrefix: '10.0.2.0/24'
+        }
+      }
     ]
   }
   resource databaseSubnet 'subnets' existing = {
@@ -60,6 +74,10 @@ resource virtualNetwork 'Microsoft.Network/virtualNetworks@2019-11-01' = {
   resource webappSubnet 'subnets' existing = {
     name: webappSubnetName
   }
+  //added for Redis Cache
+  resource cacheSubnet 'subnets' existing = {
+    name: cacheSubnetName
+  }
 }
 
 resource privateDnsZone 'Microsoft.Network/privateDnsZones@2020-06-01' = {
@@ -71,6 +89,16 @@ resource privateDnsZone 'Microsoft.Network/privateDnsZones@2020-06-01' = {
   ]
 }
 
+// added for Redis Cache
+resource privateDnsZoneCache 'Microsoft.Network/privateDnsZones@2020-06-01' = {
+  name: 'privatelink.redis.cache.windows.net'
+  location: 'global'
+  tags: tags
+  dependsOn:[
+    virtualNetwork
+  ]
+}
+
 resource privateDnsZoneLink 'Microsoft.Network/privateDnsZones/virtualNetworkLinks@2020-06-01' = {
   parent: privateDnsZone
   name: '${pgServerName}-link'
@@ -83,6 +111,54 @@ resource privateDnsZoneLink 'Microsoft.Network/privateDnsZones/virtualNetworkLin
   }
 }
 
+ //added for Redis Cache
+resource privateDnsZoneLinkCache 'Microsoft.Network/privateDnsZones/virtualNetworkLinks@2020-06-01' = {
+ parent: privateDnsZoneCache
+ name: 'privatelink.redis.cache.windows.net-applink'
+ location: 'global'
+ properties: {
+   registrationEnabled: false
+   virtualNetwork: {
+     id: virtualNetwork.id
+   }
+ }
+}
+
+
+resource cachePrivateEndpoint 'Microsoft.Network/privateEndpoints@2023-05-01' = {
+  name: cachePrivateEndpointName
+  location: location
+  properties: {
+    subnet: {
+      id: virtualNetwork::cacheSubnet.id
+    }
+    privateLinkServiceConnections: [
+      {
+        name: cachePrivateEndpointName
+        properties: {
+          privateLinkServiceId: redisCache.id
+          groupIds: [
+            'redisCache'
+          ]
+        }
+      }
+    ]
+  }
+  resource cachePvtEndpointDnsGroup 'privateDnsZoneGroups' = {
+    name: cachePvtEndpointDnsGroupName
+    properties: {
+      privateDnsZoneConfigs: [
+        {
+          name: 'privatelink-redis-cache-windows-net'
+          properties: {
+            privateDnsZoneId: privateDnsZoneCache.id
+          }
+        }
+      ]
+    }
+  }
+}
+
 resource web 'Microsoft.Web/sites@2022-03-01' = {
   name: '${prefix}-app-service'
   location: location
@@ -92,7 +168,7 @@ resource web 'Microsoft.Web/sites@2022-03-01' = {
     serverFarmId: appServicePlan.id
     siteConfig: {
       alwaysOn: true
-      linuxFxVersion: 'PYTHON|3.10'
+      linuxFxVersion: 'PYTHON|3.11'
       ftpsState: 'Disabled'
       appCommandLine: 'startup.sh'
     }
@@ -108,6 +184,9 @@ resource web 'Microsoft.Web/sites@2022-03-01' = {
       AZURE_POSTGRESQL_CONNECTIONSTRING: 'dbname=${djangoDatabase.name} host=${postgresServer.name}.postgres.database.azure.com port=5432 sslmode=require user=${postgresServer.properties.administratorLogin} password=${databasePassword}'
       SCM_DO_BUILD_DURING_DEPLOYMENT: 'true'
       SECRET_KEY: secretKey
+      //TODO: add settings for Redis Cache
+      CACHELOCATION: 'rediss://${redisCache.name}.redis.cache.windows.net:6380/0'
+      CACHEKEY: redisCache.listKeys().primaryKey
     }
   }
 
@@ -151,7 +230,7 @@ resource appServicePlan 'Microsoft.Web/serverfarms@2021-03-01' = {
   location: location
   tags: tags
   sku: {
-    name: 'B1'
+    name: 'S1'
   }
   properties: {
     reserved: true
@@ -229,5 +308,23 @@ resource djangoDatabase 'Microsoft.DBforPostgreSQL/flexibleServers/databases@202
   name: 'django'
 }
 
+//added for Redis Cache
+resource redisCache 'Microsoft.Cache/redis@2023-04-01' = {
+  location:location
+  name:cacheServerName
+  properties:{
+    sku:{
+      capacity: 1
+      family:'C'
+      name:'Standard'
+    }
+    enableNonSslPort:false
+    redisVersion:'6'
+    publicNetworkAccess:'Disabled'
+  }
+
+
+}    
+
 output WEB_URI string = 'https://${web.properties.defaultHostName}'
 output APPLICATIONINSIGHTS_CONNECTION_STRING string = applicationInsightsResources.outputs.APPLICATIONINSIGHTS_CONNECTION_STRING

requirements.txt

@@ -1,4 +1,5 @@
 Django==4.2.5
 psycopg2-binary==2.9.7
 python-dotenv==1.0.0
-whitenoise==6.5.0
+whitenoise==6.5.0
+django-redis==5.3.0

restaurant_review/templates/restaurant_review/index.html

@@ -42,6 +42,9 @@
   </style>
 {% endblock %}
 {% block content %}
+  {% if LastViewedRestaurant %}
+      <h3>Last viewed restaurant: {{ LastViewedRestaurant }}</h3>
+  {% endif %}
   <h1>Restaurants</h1>
 
   {% if restaurants %}

restaurant_review/views.py

@@ -4,6 +4,7 @@
 from django.urls import reverse
 from django.utils import timezone
 from django.views.decorators.csrf import csrf_exempt
+from django.views.decorators.cache import cache_page
 
 from restaurant_review.models import Restaurant, Review
 
@@ -12,12 +13,15 @@
 def index(request):
     print('Request for index page received')
     restaurants = Restaurant.objects.annotate(avg_rating=Avg('review__rating')).annotate(review_count=Count('review'))
-    return render(request, 'restaurant_review/index.html', {'restaurants': restaurants})
-
+    lastViewedRestaurant = request.session.get("lastViewedRestaurant", False)
+    print(lastViewedRestaurant)
+    return render(request, 'restaurant_review/index.html', {'LastViewedRestaurant': lastViewedRestaurant, 'restaurants': restaurants})
 
+@cache_page(60)
 def details(request, id):
     print('Request for restaurant details page received')
     restaurant = get_object_or_404(Restaurant, pk=id)
+    request.session["lastViewedRestaurant"] = restaurant.name
     return render(request, 'restaurant_review/details.html', {'restaurant': restaurant})