How To Access Azure Blob Storage Web App Python

Flask and Azure Table Storage on Azure with Python Tools 2.2 for Visual Studio

In this tutorial, we'll use Python Tools for Visual Studio to create a simple polls web app using one of the PTVS sample templates. This tutorial is also available as a video.

The polls web app defines an abstraction for its repository, so you can easily switch between different types of repositories (In-Memory, Azure Table Storage, MongoDB).

We'll learn how to create an Azure Storage account, how to configure the web app to use Azure Table Storage, and how to publish the web app to Azure App Service Web Apps.

See the Python Developer Center for more articles that cover development of Azure App Service Web Apps with PTVS using Bottle, Flask and Django web frameworks, with MongoDB, Azure Table Storage, MySQL and SQL Database services. While this article focuses on App Service, the steps are similar when developing Azure Cloud Services.

Prerequisites

Visual Studio 2015
Python Tools 2.2 for Visual Studio
Python Tools 2.2 for Visual Studio Samples VSIX
Azure SDK Tools for VS 2015
Python 2.7 32-bit or Python 3.4 32-bit

[AZURE.INCLUDE create-account-and-websites-note]

[AZURE.NOTE] If you want to get started with Azure App Service before signing up for an Azure account, go to Try App Service, where you can immediately create a short-lived starter web app in App Service. No credit cards required; no commitments.

Create the Project

In this section, we'll create a Visual Studio project using a sample template. We'll create a virtual environment and install required packages. Then we'll run the application locally using the default in-memory repository.

In Visual Studio, select File, New Project.
The project templates from the Python Tools 2.2 for Visual Studio Samples VSIX are available under Python, Samples. Select Polls Flask Web Project and click OK to create the project.
You will be prompted to install external packages. Select Install into a virtual environment.
Select Python 2.7 or Python 3.4 as the base interpreter.
Confirm that the application works by pressing F5. By default, the application uses an in-memory repository which doesn't require any configuration. All data is lost when the web server is stopped.
Click Create Sample Polls, then click on a poll and vote.

Create an Azure Storage Account

To use storage operations, you need an Azure storage account. You can create a storage account by following these steps.

Log into the Azure Portal.
Click the New icon on the top left of the Portal, then click Data + Storage > Storage Account. Click on Create, then give the storage account a unique name and create a new resource group for it.

When the storage account has been created, the Notifications button will flash a green SUCCESS and the storage account's blade is open to show that it belongs to the new resource group you created.
Click the Access Keys part in the storage account's blade. Take note of the account name and the key1.

We will need this information to configure your project in the next section.

Configure the Project

In this section, we'll configure our application to use the storage account we just created. We'll see how to obtain connection settings from the Azure Portal. Then we'll run the application locally.

In Visual Studio, right-click on your project node in Solution Explorer and select Properties. Click on the Debug tab.
Set the values of environment variables required by the application in Debug Server Command, Environment.
```
                  REPOSITORY_NAME=azuretablestorage STORAGE_NAME=<storage account name> STORAGE_KEY=<primary access key>                                  
```
This will set the environment variables when you Start Debugging. If you want the variables to be set when you Start Without Debugging, set the same values under Run Server Command as well.

Alternatively, you can define environment variables using the Windows Control Panel. This is a better option if you want to avoid storing credentials in source code / project file. Note that you will need to restart Visual Studio for the new environment values to be available to the application.
The code that implements the Azure Table Storage repository is in models/azuretablestorage.py. See the documentation for more information on how to use Table Service from Python.
Run the application with F5. Polls that are created with Create Sample Polls and the data submitted by voting will be serialized in Azure Table Storage.

[AZURE.NOTE] The Python 2.7 Virtual Environment may cause an exception break in Visual Studio. Press F5 to continue loading the web project.
Browse to the About page to verify that the application is using the Azure Table Storage repository.

Explore the Azure Table Storage

It's easy to view and edit storage tables using Cloud Explorer in Visual Studio. In this section we'll use Server Explorer to view the contents of the polls application tables.

[AZURE.NOTE] This requires Microsoft Azure Tools to be installed, which are available as part of the Azure SDK for .NET.

Open Cloud Explorer. Expand Storage Accounts, your storage account, then Tables.
Double-click on the polls or choices table to view the contents of the table in a document window, as well as add/remove/edit entities.

Publish the web app to Azure App Service

The Azure .NET SDK provides an easy way to deploy your web app to Azure App Service.

In Solution Explorer, right-click on the project node and select Publish.
Click on Microsoft Azure Web Apps.
Click on New to create a new web app.
Fill in the following fields and click Create.
- Web App name
- App Service plan
- Resource group
- Region
- Leave Database server set to No database
Accept all other defaults and click Publish.
Your web browser will open automatically to the published web app. If you browse to the about page, you'll see that it uses the In-Memory repository, not the Azure Table Storage repository.

That's because the environment variables are not set on the Web Apps instance in Azure App Service, so it uses the default values specified in settings.py.

Configure the Web Apps instance

In this section, we'll configure environment variables for the Web Apps instance.

In Azure Portal, open the web app's blade by clicking Browse > App Services > your web app name.
In your web app's blade, click All Settings, then click Application Settings.
Scroll down to the App settings section and set the values for REPOSITORY_NAME, STORAGE_NAME and STORAGE_KEY as described in the Configure the project section above.
Click on Save. After you've received the notifications that the changes were applied, click on Browse from the Web app main blade.
You should see the web app working as expected, using the Azure Table Storage repository.

Congratulations!

Next steps

Follow these links to learn more about Python Tools for Visual Studio, Flask and Azure Table Storage.

Python Tools for Visual Studio Documentation
- Web Projects
- Cloud Service Projects
- Remote Debugging on Microsoft Azure
Flask Documentation
Azure Storage
Azure SDK for Python
How to Use the Table Storage Service from Python

What's changed

For a guide to the change from Websites to App Service see: Azure App Service and Its Impact on Existing Azure Services