• An Azure account with an active subscription. If you don't have an Azure account, youcan create one for free.
• Knowledge of Python with FastAPI development

• An Azure account with an active subscription. If you don't have an Azure account, youcan create one for free.
• Azure Developer CLI installed. You can follow the steps with theAzure Cloud Shell because it already has Azure Developer CLI installed.
• Knowledge of Python with FastAPI development

• Windows
• macOS/Linux

py -m venv .venv.venv\scripts\activate

python3 -m venv .venvsource .venv/bin/activate

1. Create App Service and PostgreSQL

In this step, you create the Azure resources. The steps used in this tutorial create a set of secure-by-default resources that include App Service and Azure Database for PostgreSQL. For the creation process, you specify:

• TheName for the web app. It's the name used as part of the DNS name for your webapp.
• TheRegion to run the app physically in the world.
• TheRuntime stack for the app. It's where you select the version of Python to use for your app.
• TheHosting plan for the app. It's the pricing tier that includes the set of features and scaling capacity for your app.
• TheResource Group for the app. A resource group lets you group (in a logical container) all the Azure resources needed for the application.

Sign in to theAzure portal and follow these steps to create your Azure App Service resources.

2. Verify connection settings

The creation wizard generated the connectivity variables for you already asapp settings. App settings are one way to keep connection secrets out of your code repository. When you're ready to move your secrets to a more secure location, here's anarticle on storing in Azure Key Vault.

3. Deploy sample code

In this step, you configure GitHub deployment using GitHub Actions. It's just one of many ways to deploy to App Service, but also a great way to have continuous integration in your deployment process. By default, everygit push to your GitHub repository will kick off the build and deploy action.

Having issues? Check theTroubleshooting guide.

4. Generate database schema

In previous section, you addedsrc/entrypoint.sh as the startup command for your app.entrypoint.sh contains the following line:python3 src/fastapi_app/seed_data.py. This command migrates your database. In the sample app, it only ensures that the correct tables are created in your database. It doesn't populate these tables with any data.

In this section, you'll run this command manually for demonstration purposes. With the PostgreSQL database protected by the virtual network, the easiest way to run the command is in an SSH session with the App Service container.

5. Browse to the app

6. Stream diagnostic logs

The sample app uses the Python Standard Library logging module to help you diagnose issues with your application. The sample app includes calls to the logger as shown in the following code.

@app.get("/", response_class=HTMLResponse)async def index(request: Request, session: Session = Depends(get_db_session)):    logger.info("root called")    statement = (        select(Restaurant, func.avg(Review.rating).label("avg_rating"), func.count(Review.id).label("review_count"))        .outerjoin(Review, Review.restaurant == Restaurant.id)        .group_by(Restaurant.id)    )

Events can take several minutes to show up in the diagnostic logs. Learn more about logging in Python apps in the series onsetting up Azure Monitor for your Python application.

7. Clean up resources

When you're finished, you can delete all of the resources from your Azure subscription by deleting the resource group.

1. Create Azure resources and deploy a sample app

In this step, you create the Azure resources and deploy a sample app to App Service on Linux. The steps used in this tutorial create a set of secure-by-default resources that include App Service and Azure Database for PostgreSQL.

1. If you haven't already, clone the sample repository'sstarter-no-infra branch in a local terminal.

   git clone -b starter-no-infra https://github.com/Azure-Samples/msdocs-fastapi-postgresql-sample-appcd msdocs-fastapi-postgresql-sample-app

   This cloned branch is your starting point. It contains a simple data-drive FastAPI application.

2. From the repository root, runazd init.

   azd init --template msdocs-fastapi-postgresql-sample-app

3. When prompted, give the following answers:

   Question	Answer
   The current directory is not empty. Would you like to initialize a project here in '<your-directory>'?	Y
   What would you like to do with these files?	Keep my existing files unchanged
   Enter a new environment name	Type a unique name. The azd template uses this name as part of the DNS name of your web app in Azure (<app-name>.azurewebsites.net). Alphanumeric characters and hyphens are allowed.

4. Run theazd up command to provision the necessary Azure resources and deploy the app code. If you aren't already signed-in to Azure, the browser will launch and ask you to sign-in. Theazd up command will also prompt you to select the desired subscription and location to deploy to.

   azd up

   Theazd up command can take several minutes to complete. It also compiles and deploys your application code. While it's running, the command provides messages about the provisioning and deployment process, including a link to the deployment in Azure. When it finishes, the command also displays a link to the deploy application.

   This azd template contains files (azure.yaml and theinfra directory) that generate a secure-by-default architecture with the following Azure resources:

   • Resource group → The container for all the created resources.
   • App Service plan → Defines the compute resources for App Service. A Linux plan in theB1 tier is specified.
   • App Service → Represents your app and runs in the App Service plan.
   • Virtual network → Integrated with the App Service app and isolates back-end network traffic.
   • Azure Database for PostgreSQL flexible server → Accessible only from within the virtual network. A database and a user are created for you on the server.
   • Private DNS zone → Enables DNS resolution of the PostgreSQL server in the virtual network.
   • Log Analytics workspace → Acts as the target container for your app to ship its logs, where you can also query the logs.

5. When theazd up command completes, note down the values for theSubscription ID (Guid), theApp Service, and theResource Group in the output. You use them in the following sections. Your output will look similar to the following (partial) output:

   Subscription: Your subscription name (1111111-1111-1111-1111-111111111111)Location: East US  You can view detailed progress in the Azure Portal:  https://portal.azure.com/#view/HubsExtension/DeploymentDetailsBlade/~/overview/id/%2Fsubscriptions%2F1111111-1111-1111-1111-111111111111%2Fproviders%2FMicrosoft.Resources%2Fdeployments%2Fyourenv-1721867673  (✓) Done: Resource group: yourenv-rg  (✓) Done: Virtual Network: yourenv-e2najjk4vewf2-vnet  (✓) Done: App Service plan: yourenv-e2najjk4vewf2-service-plan  (✓) Done: Log Analytics workspace: yourenv-e2najjk4vewf2-workspace  (✓) Done: Application Insights: yourenv-e2najjk4vewf2-appinsights  (✓) Done: Portal dashboard: yourenv-e2najjk4vewf2-dashboard  (✓) Done: App Service: yourenv-e2najjk4vewf2-app-service  (✓) Done: Azure Database for PostgreSQL flexible server: yourenv-e2najjk4vewf2-postgres-server  (✓) Done: Cache for Redis: yourenv-e2najjk4vewf2-redisCache  (✓) Done: Private Endpoint: cache-privateEndpointSUCCESS: Your application was provisioned in Azure in 32 minutes.You can view the resources created under the resource group yourenv-rg in Azure Portal:https://portal.azure.com/#@/resource/subscriptions/1111111-1111-1111-1111-111111111111/resourceGroups/yourenv-rg/overviewDeploying services (azd deploy)  (✓) Done: Deploying service web  - Endpoint: https://yourenv-e2najjk4vewf2-app-service.azurewebsites.net/

2. Examine the database connection string

The azd template generates the connectivity variables for you asapp settings. App settings are one way to keep connection secrets out of your code repository.

1. In theinfra/resources.bicep file, find the app settings and find the setting forAZURE_POSTGRESQL_CONNECTIONSTRING.

   resource appSettings 'config' = {  name: 'appsettings'  properties: {    SCM_DO_BUILD_DURING_DEPLOYMENT: 'true'    AZURE_POSTGRESQL_CONNECTIONSTRING: 'dbname=${pythonAppDatabase.name} host=${postgresServer.name}.postgres.database.azure.com port=5432 sslmode=require user=${postgresServer.properties.administratorLogin} password=${databasePassword}'    SECRET_KEY: secretKey    AZURE_REDIS_CONNECTIONSTRING: 'rediss://:${redisCache.listKeys().primaryKey}@${redisCache.name}.redis.cache.windows.net:6380/0'  }}

2. AZURE_POSTGRESQL_CONNECTIONSTRING contains the connection string to the Postgres database in Azure. You need to use it in your code to connect to it. You can find the code that uses this environment variable insrc/fastapi/models.py:

   sql_url = ""if os.getenv("WEBSITE_HOSTNAME"):    logger.info("Connecting to Azure PostgreSQL Flexible server based on AZURE_POSTGRESQL_CONNECTIONSTRING...")    env_connection_string = os.getenv("AZURE_POSTGRESQL_CONNECTIONSTRING")    if env_connection_string is None:        logger.info("Missing environment variable AZURE_POSTGRESQL_CONNECTIONSTRING")    else:        # Parse the connection string        details = dict(item.split('=') for item in env_connection_string.split())        # Properly format the URL for SQLAlchemy        sql_url = (            f"postgresql://{quote_plus(details['user'])}:{quote_plus(details['password'])}"            f"@{details['host']}:{details['port']}/{details['dbname']}?sslmode={details['sslmode']}"        )else:    logger.info("Connecting to local PostgreSQL server based on .env file...")    load_dotenv()    POSTGRES_USERNAME = os.environ.get("DBUSER")    POSTGRES_PASSWORD = os.environ.get("DBPASS")    POSTGRES_HOST = os.environ.get("DBHOST")    POSTGRES_DATABASE = os.environ.get("DBNAME")    POSTGRES_PORT = os.environ.get("DBPORT", 5432)    sql_url = f"postgresql://{POSTGRES_USERNAME}:{POSTGRES_PASSWORD}@{POSTGRES_HOST}:{POSTGRES_PORT}/{POSTGRES_DATABASE}"engine = create_engine(sql_url)

3. Examine the startup command

Azure App Service requires a startup command to run your FastAPI app. The azd template sets this command for you in your App Service instance.

1. In theinfra/resources.bicep file, find the declaration for your web site and then find the setting forappCommandLine. This is the setting for your startup command.

   resource web 'Microsoft.Web/sites@2022-03-01' = {  name: '${prefix}-app-service'  location: location  tags: union(tags, { 'azd-service-name': 'web' })  kind: 'app,linux'  properties: {    serverFarmId: appServicePlan.id    siteConfig: {      alwaysOn: true      linuxFxVersion: 'PYTHON|3.11'      ftpsState: 'Disabled'      appCommandLine: 'src/entrypoint.sh'      minTlsVersion: '1.2'    }    httpsOnly: true  }  identity: {    type: 'SystemAssigned'  }

2. The startup command runs the filesrc/entrypoint.sh. Examine the code in that file to understand the commands that App Service runs to start your app:

   #!/bin/bashset -epython3 -m pip install --upgrade pippython3 -m pip install -e srcpython3 src/fastapi_app/seed_data.pypython3 -m gunicorn fastapi_app:app -c src/gunicorn.conf.py

To learn more about app configuration and startup in App Service, seeConfigure a Linux Python app for Azure App Service.

4. Generate database schema

You might have noticed in the previous section thatentrypoint.sh contains the following line:python3 src/fastapi_app/seed_data.py. This command migrates your database. In the sample app, it only ensures that the correct tables are created in your database. It doesn't populate these tables with any data.

In this section, you'll run this command manually for demonstration purposes. With the PostgreSQL database protected by the virtual network, the easiest way to run the command is in an SSH session with the App Service container.

1. Use the value of theApp Service that you noted previously in the azd output to construct the URL for the SSH session and navigate to it in the browser:

2. In the SSH terminal, runpython3 src/fastapi_app/seed_data.py. If it succeeds, App Service isconnecting successfully to the database.

   

   Note

   Only changes to files in/home can persist beyond app restarts. Changes outside of/home aren't persisted.

5. Browse to the app

1. In the azd output, find the URL of your app and navigate to it in the browser. The URL looks like this in the AZD output:

    Deploying services (azd deploy)   (✓) Done: Deploying service web   - Endpoint: <URL>

2. Add a few restaurants to the list.

   

   Congratulations, you're running a web app in Azure App Service, with secure connectivity to Azure Database for PostgreSQL.

6. Stream diagnostic logs

Azure App Service can capture logs to help you diagnose issues with your application. For convenience, the azd template has alreadyenabled logging to the local file system.

The sample app uses the Python Standard Library logging module to output logs. The sample app includes calls to the logger as shown below.

@app.get("/", response_class=HTMLResponse)async def index(request: Request, session: Session = Depends(get_db_session)):    logger.info("root called")    statement = (        select(Restaurant, func.avg(Review.rating).label("avg_rating"), func.count(Review.id).label("review_count"))        .outerjoin(Review, Review.restaurant == Restaurant.id)        .group_by(Restaurant.id)    )

To access the log stream, open your app in the Azure portal. SelectMonitoring >Log stream.

Events can take several minutes to show up in the diagnostic logs. Learn more about logging in Python apps in the series onsetting up Azure Monitor for your Python application.

7. Clean up resources

To delete all Azure resources in the current deployment environment, runazd down.

azd down

 Secure with custom domain and certificate

Configure Python app