App Services

Introduction

Azure App Service is a fully managed platform for hosting web applications, mobile backends, and RESTful APIs without infrastructure overhead. It supports multiple runtimes including .NET, Java, Node.js, Python, and PHP on both Windows and Linux, or as custom containers. For more information, see the App Service overview.

LocalStack for Azure provides a local environment for building and testing applications that make use of Azure App Services. The supported APIs are available on our API Coverage section, which provides information on the extent of Web App’s integration with LocalStack.

Getting started

This guide is designed for users new to Web App and assumes basic knowledge of the Azure CLI and our azlocal wrapper script.

Launch LocalStack using your preferred method. For more information, see Introduction to LocalStack for Azure. Once the container is running, enable Azure CLI interception by running:

azlocal start-interception

This command points the az CLI away from the public Azure management REST API and toward the LocalStack for Azure emulator API. To revert this configuration, run:

azlocal stop-interception

This reconfigures the az CLI to send commands to the official Azure management REST API.

Create a resource group

Create a resource group for your Web App resources:

az group create \
  --name rg-web-demo \
  --location westeurope

Output

{
  "name": "rg-web-demo",
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-web-demo",
  "location": "westeurope",
  "properties": {
    "provisioningState": "Succeeded"
  },
  ...
}

Create an App Service plan

Create an App Service plan that will host the web app:

az appservice plan create \
  --name asp-web-doc89 \
  --resource-group rg-web-demo \
  --location westeurope \
  --sku B1

Output

{
  "name": "asp-web-doc89",
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-web-demo/providers/Microsoft.Web/serverfarms/asp-web-doc89",
  "location": "westeurope",
  "provisioningState": "Succeeded",
  "sku": {
    "name": "B1",
    "tier": "Basic",
    ...
  },
  ...
}

Create and inspect a Web App

Create a web app using a Python runtime:

az webapp create \
  --name ls-web-doc89 \
  --resource-group rg-web-demo \
  --plan asp-web-doc89 \
  --runtime "PYTHON:3.11"

Output

{
  "name": "ls-web-doc89",
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-web-demo/providers/Microsoft.Web/sites/ls-web-doc89",
  "type": "Microsoft.Web/sites",
  "location": "westeurope",
  "defaultHostName": "ls-web-doc89.azurewebsites.azure.localhost.localstack.cloud:4566",
  "state": "Running",
  ...
}

Get the web app:

az webapp show \
  --name ls-web-doc89 \
  --resource-group rg-web-demo

Read and update web app configuration

Read the current web app configuration:

az webapp config show \
  --name ls-web-doc89 \
  --resource-group rg-web-demo

Output

{
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-web-demo/providers/Microsoft.Web/sites/ls-web-doc89/config/web",
  "linuxFxVersion": "PYTHON|3.11",
  "http20Enabled": true,
  "alwaysOn": false,
  "ftpsState": "FtpsOnly",
  ...
}

Update the web app configuration:

az webapp config set \
  --name ls-web-doc89 \
  --resource-group rg-web-demo \
  --always-on false \
  --http20-enabled true

Output

{
  "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/rg-web-demo/providers/Microsoft.Web/sites/ls-web-doc89",
  "http20Enabled": true,
  "alwaysOn": false,
  ...
}

Configure application settings

Set an application setting that instructs the SCM endpoint to build the application during deployment:

az webapp config appsettings set \
  --name ls-web-doc89 \
  --resource-group rg-web-demo \
  --settings SCM_DO_BUILD_DURING_DEPLOYMENT="true"

Output

[
  {
    "name": "SCM_DO_BUILD_DURING_DEPLOYMENT",
    "slotSetting": false,
    "value": "true"
  }
]

Verify the setting was applied:

az webapp config appsettings list \
  --name ls-web-doc89 \
  --resource-group rg-web-demo \
  --query "[?name=='SCM_DO_BUILD_DURING_DEPLOYMENT']"

Output

[
  {
    "name": "SCM_DO_BUILD_DURING_DEPLOYMENT",
    "slotSetting": false,
    "value": "true"
  }
]

Deploy a Python application

Create a minimal Flask application and package it as a zip archive for deployment:

mkdir python_webapp && cd python_webapp
cat > app.py << 'EOF'
import json
from flask import Flask
app = Flask(__name__)
@app.route("/")
def index():
    return json.dumps({"status": "Great Success!"})
if __name__ == "__main__":
    app.run()
EOF
cat > requirements.txt << 'EOF'
Flask==3.0.3
gunicorn==23.0.0
Werkzeug==3.0.4
EOF
zip -r ../python_webapp.zip .
cd ..

Deploy the zip package to the web app:

az webapp deploy \
  --name ls-web-doc89 \
  --resource-group rg-web-demo \
  --src-path python_webapp.zip \
  --type zip \
  --async true

Output

{
  "status": 4,
  "complete": true,
  "active": true,
  ...
}

Verify that the web app is in the Running state:

az webapp show \
  --name ls-web-doc89 \
  --resource-group rg-web-demo \
  --query "state" \
  --output tsv

Output

Running

Delete and verify

Delete the web app and verify it no longer appears:

az webapp delete \
  --name ls-web-doc89 \
  --resource-group rg-web-demo
az webapp list --resource-group rg-web-demo

Output

[]

Features

The App Service emulator supports the following features:

• App Service Plans: Create, get, list (subscription-wide and by resource group), and delete App Service Plans.
• Web Apps: Create, get, list (subscription-wide and by resource group), and delete web apps.
• Application settings: List and update application settings via az webapp config appsettings set and az webapp config appsettings list.
• Site configuration: Read and update site configuration properties including http20Enabled, alwaysOn, ftpsState, and linuxFxVersion.
• Zip deployment: Deploy application packages via az webapp deploy --type zip, triggering an Oryx-based container build.
• SCM deployment endpoints: Zip deploy and publish endpoints accessible via the SCM subdomain.
• Deployment lifecycle: Create, get, list, delete, and retrieve logs for individual deployments.
• Deployment status: Poll production site deployment status for async deployments.
• Source control integration: Create, get, update, delete, and sync source control configuration.
• Function App support: List functions, list function keys, sync function triggers, sync functions, and query sync status.
• Publishing credentials: Retrieve publishing credentials and publishing profile XML.
• Diagnostic logs configuration: Get and update HTTP and application log settings.
• Azure Storage account mounts: List and update Azure Storage account configurations on a site.
• Authentication settings: Read auth settings (v1 and v2) for a site.
• Publishing policy controls: Get and update FTP and SCM publishing credential policies.
• Connection strings: List connection strings for a site.
• Managed identity: System-assigned and user-assigned managed identities for web apps.
• Instance identifiers: List web app instance identifiers.
• Slot configuration names: List the names of settings and connection strings that are slot-specific.
• Runtime stack enumeration: List available web app and Function App runtime stacks for both Linux and Windows.
• Geo region listing: List available geographic regions for App Service deployments.
• Name availability check: Validate that a web app name is available within the subscription.

Limitations

• Deployment slots: Only the production slot is supported. Staging slots and slot-swap operations are not implemented.
• Custom domains: Binding custom hostnames to a web app is not supported. Apps are accessible only via the emulator-assigned *.azurewebsites.azure.localhost.localstack.cloud hostname.
• Managed TLS certificates: SSL/TLS certificate provisioning and binding are not implemented.
• VNet integration and private endpoints: Network isolation features are not enforced.
• Autoscaling: App Service Plan capacity settings are accepted but not enforced by the emulator.
• Backup and restore: The backup configuration endpoint returns an empty response. No backup or restore operations are performed.
• EasyAuth (authentication and authorization): Auth settings endpoints return fixed defaults. No identity provider flow or token validation is active.
• FTP/S deployments: FTP publishing is not available. Use az webapp deploy --type zip or the SCM zip-deploy endpoint instead.
• Publishing policy persistence: The update_ftp_allowed and update_scm_allowed endpoints accept requests but do not persist policy changes.
• No data persistence across restarts: Web App state is held in memory and is lost when the LocalStack emulator is stopped or restarted.

Configuration

The behavior of the App Service emulator can be customized using the following environment variables.

Variable	Default	Type	Description
ALLOW_MULTIPLE_ORYX_DEPLOYMENTS	"0"	Boolean	Allow multiple Oryx build containers to run concurrently for a single app.
CONTAINER_CREATION_RETRIES	"5" (web) / "3" (functions)	Integer	Number of attempts to create a container if the initial attempt fails.
DOCKER_PULL_TIMEOUT	"120"	Integer (seconds)	Maximum time to wait for a Docker image pull to complete.
PORT_RESERVATION_DURATION	"120"	Integer (seconds)	Duration for which a host port is reserved during container startup.
ORYX_BUILD_CONTAINER_IMAGE_TO_USE	Oryx LTS build image	String	Specific Oryx build image to use when building application containers.
USE_LATEST_ORYX_BUILD_CONTAINER_IMAGE	"0"	Boolean	Automatically fetch and use the latest Oryx build container image.
AZURE_FUNCTIONS_CORE_TOOLS_VERSION	"4.2.2"	String	Version of Azure Functions Core Tools used for Function App deployments.

Samples

The following samples demonstrate how to use App Services with LocalStack for Azure:

• Web App and Cosmos DB for MongoDB API
• Web App and Cosmos DB for NoSQL API
• Web App and Managed Identities
• Web App and SQL Database

API Coverage

Operation ▲	Implemented ▼

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