Tutorial: Connect to Azure databases from App Service without secrets using a managed identity
Άρθρο
App Service provides a highly scalable, self-patching web hosting service in Azure. It also provides a managed identity for your app, which is a turn-key solution for securing access to Azure databases, including:
Managed identities in App Service make your app more secure by eliminating secrets from your app, such as credentials in the connection strings. This tutorial shows you how to connect to the above-mentioned databases from App Service using managed identities.
What you will learn:
Configure a Microsoft Entra user as an administrator for your Azure database.
Connect to your database as the Microsoft Entra user.
Configure a system-assigned or user-assigned managed identity for an App Service app.
Grant database access to the managed identity.
Connect to the Azure database from your code (.NET Framework 4.8, .NET 6, Node.js, Python, Java) using a managed identity.
Connect to the Azure database from your development environment using the Microsoft Entra user.
Create an app in App Service based on .NET, Node.js, Python, or Java.
Create a database server with Azure SQL Database, Azure Database for MySQL, or Azure Database for PostgreSQL.
You should be familiar with the standard connectivity pattern (with username and password) and be able to connect successfully from your App Service app to your database of choice.
If you prefer to run CLI reference commands locally, install the Azure CLI. If you're running on Windows or macOS, consider running Azure CLI in a Docker container. For more information, see How to run the Azure CLI in a Docker container.
If you're using a local installation, sign in to the Azure CLI by using the az login command. To finish the authentication process, follow the steps displayed in your terminal. For other sign-in options, see Sign in with the Azure CLI.
When you're prompted, install the Azure CLI extension on first use. For more information about extensions, see Use extensions with the Azure CLI.
Run az version to find the version and dependent libraries that are installed. To upgrade to the latest version, run az upgrade.
1. Install the Service Connector passwordless extension
Install the latest Service Connector passwordless extension for the Azure CLI:
az extension add --name serviceconnector-passwordless --upgrade
Note
Please check the extension "serviceconnector-passwordless" version is "2.0.2" or higher by running az version. You may need to upgrade Azure CLI first to upgrade the extension version.
2. Create a passwordless connection
Next, create a passwordless connection with Service Connector.
Tip
The Azure portal can help you compose the commands below. In the Azure portal, go to your Azure App Service resource, select Service Connector from the left menu and select Create. Fill out the form with all required parameters. Azure automaticaly generates the connection creation command, which you can copy to use in the CLI or execute in Azure Cloud Shell.
For Azure Database for MySQL - Flexible Server, you must first manually set up Microsoft Entra authentication, which requires a separate user-assigned managed identity and specific Microsoft Graph permissions. This step can't be automated.
Next, if you have created tables and sequences in PostgreSQL flexible server before using Service Connector, you need to connect as the owner and grant permission to <aad-username> created by Service Connector. The username from the connection string or configuration set by Service Connector should look like aad_<connection name>. If you use the Azure portal, select the expand button next to the Service Type column and get the value. If you use Azure CLI, check configurations in the CLI command output.
Then, execute the query to grant permission
az extension add --name rdbms-connect
az postgres flexible-server execute -n <postgres-name> -u <owner-username> -p "<owner-password>" -d <database-name> --querytext "GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO \"<aad-username>\";GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public TO \"<aad username>\";"
The <owner-username> and <owner-password> is the owner of the existing table that can grant permissions to others. <aad-username> is the user created by Service Connector. Replace them with the actual value.
Validate the result with the command:
az postgres flexible-server execute -n <postgres-name> -u <owner-username> -p "<owner-password>" -d <database-name> --querytext "SELECT distinct(table_name) FROM information_schema.table_privileges WHERE grantee='<aad-username>' AND table_schema='public';" --output table
This Service Connector command completes the following tasks in the background:
Enable system-assigned managed identity, or assign a user identity for the app <server-name> hosted by Azure App Service.
Set the Microsoft Entra admin to the current signed-in user.
Add a database user for the system-assigned managed identity or user-assigned managed identity. Grant all privileges of the database <database-name> to this user. The username can be found in the connection string in preceding command output.
Set configurations named AZURE_MYSQL_CONNECTIONSTRING, AZURE_POSTGRESQL_CONNECTIONSTRING, or AZURE_SQL_CONNECTIONSTRING to the Azure resource based on the database type.
For App Service, the configurations are set in the App Settings blade.
If you encounter any problem when creating a connection, refer to Troubleshooting for help.
Get the Azure SQL Database connection string from the environment variable added by Service Connector.
using Microsoft.Data.SqlClient;
// AZURE_SQL_CONNECTIONSTRING should be one of the following:
// For system-assigned managed identity:"Server=tcp:<server-name>.database.windows.net;Database=<database-name>;Authentication=Active Directory Default;TrustServerCertificate=True"
// For user-assigned managed identity: "Server=tcp:<server-name>.database.windows.net;Database=<database-name>;Authentication=Active Directory Default;User Id=<client-id-of-user-assigned-identity>;TrustServerCertificate=True"
string connectionString =
Environment.GetEnvironmentVariable("AZURE_SQL_CONNECTIONSTRING")!;
using var connection = new SqlConnection(connectionString);
connection.Open();
Get the Azure SQL Database connection configurations from the environment variable added by Service Connector. Uncomment the part of the code snippet for the authentication type you want to use.
import os;
import pyodbc
server = os.getenv('AZURE_SQL_SERVER')
port = os.getenv('AZURE_SQL_PORT')
database = os.getenv('AZURE_SQL_DATABASE')
authentication = os.getenv('AZURE_SQL_AUTHENTICATION') # The value should be 'ActiveDirectoryMsi'
# Uncomment the following lines according to the authentication type.
# For system-assigned managed identity.
# connString = f'Driver={{ODBC Driver 18 for SQL Server}};Server={server},{port};Database={database};Authentication={authentication};Encrypt=yes;'
# For user-assigned managed identity.
# client_id = os.getenv('AZURE_SQL_USER')
# connString = f'Driver={{ODBC Driver 18 for SQL Server}};Server={server},{port};Database={database};UID={client_id};Authentication={authentication};Encrypt=yes;'
conn = pyodbc.connect(connString)
Get the Azure SQL Database connection configurations from the environment variables added by Service Connector. Uncomment the part of the code snippet for the authentication type you want to use.
Connectivity to the Azure Database for MySQL in your code follows the DefaultAzureCredential pattern for all language stacks. DefaultAzureCredential is flexible enough to adapt to both the development environment and the Azure environment. When running locally, it can retrieve the logged-in Azure user from the environment of your choice (Visual Studio, Visual Studio Code, Azure CLI, or Azure PowerShell). When running in Azure, it retrieves the managed identity. So it's possible to have connectivity to database both at development time and in production. The pattern is as follows:
Instantiate a DefaultAzureCredential from the Azure Identity client library. If you're using a user-assigned identity, specify the client ID of the identity.
Get an access token for Azure Database for MySQL: https://ossrdbms-aad.database.windows.net/.default.
For .NET, get an access token for the managed identity using a client library such as Azure.Identity. Then use the access token as a password to connect to the database. When using the code below, make sure you uncomment the part of the code snippet that corresponds to the authentication type you want to use.
using Azure.Core;
using Azure.Identity;
using MySqlConnector;
// Uncomment the following lines according to the authentication type.
// For system-assigned managed identity.
// var credential = new DefaultAzureCredential();
// For user-assigned managed identity.
// var credential = new DefaultAzureCredential(
// new DefaultAzureCredentialOptions
// {
// ManagedIdentityClientId = Environment.GetEnvironmentVariable("AZURE_MYSQL_CLIENTID");
// });
var tokenRequestContext = new TokenRequestContext(
new[] { "https://ossrdbms-aad.database.windows.net/.default" });
AccessToken accessToken = await credential.GetTokenAsync(tokenRequestContext);
// Open a connection to the MySQL server using the access token.
string connectionString =
$"{Environment.GetEnvironmentVariable("AZURE_MYSQL_CONNECTIONSTRING")};Password={accessToken.Token}";
using var connection = new MySqlConnection(connectionString);
Console.WriteLine("Opening connection using access token...");
await connection.OpenAsync();
// do something
Add the following dependencies in your pom.xml file:
Authenticate with an access token from the azure-identity library. Get the connection information from the environment variable added by Service Connector. When using the code below, make sure you uncomment the part of the code snippet that corresponds to the authentication type you want to use.
from azure.identity import ManagedIdentityCredential, ClientSecretCredential
import mysql.connector
import os
# Uncomment the following lines according to the authentication type.
# For system-assigned managed identity.
# cred = ManagedIdentityCredential()
# For user-assigned managed identity.
# managed_identity_client_id = os.getenv('AZURE_MYSQL_CLIENTID')
# cred = ManagedIdentityCredential(client_id=managed_identity_client_id)
# acquire token
accessToken = cred.get_token('https://ossrdbms-aad.database.windows.net/.default')
# open connect to Azure MySQL with the access token.
host = os.getenv('AZURE_MYSQL_HOST')
database = os.getenv('AZURE_MYSQL_NAME')
user = os.getenv('AZURE_MYSQL_USER')
password = accessToken.token
cnx = mysql.connector.connect(user=user,
password=password,
host=host,
database=database)
cnx.close()
Get an access token using @azure/identity and the Azure MySQL database information from the environment variables added by Service Connector. When using the code below, make sure you uncomment the part of the code snippet that corresponds to the authentication type you want to use.
import { DefaultAzureCredential,ClientSecretCredential } from "@azure/identity";
const mysql = require('mysql2');
// Uncomment the following lines according to the authentication type.
// for system-assigned managed identity
// const credential = new DefaultAzureCredential();
// for user-assigned managed identity
// const clientId = process.env.AZURE_MYSQL_CLIENTID;
// const credential = new DefaultAzureCredential({
// managedIdentityClientId: clientId
// });
// acquire token
var accessToken = await credential.getToken('https://ossrdbms-aad.database.windows.net/.default');
const connection = mysql.createConnection({
host: process.env.AZURE_MYSQL_HOST,
user: process.env.AZURE_MYSQL_USER,
password: accessToken.token,
database: process.env.AZURE_MYSQL_DATABASE,
port: process.env.AZURE_MYSQL_PORT,
ssl: process.env.AZURE_MYSQL_SSL
});
connection.connect((err) => {
if (err) {
console.error('Error connecting to MySQL database: ' + err.stack);
return;
}
console.log('Connected to MySQL database');
});
Connectivity to the Azure Database for PostgreSQL in your code follows the DefaultAzureCredential pattern for all language stacks. DefaultAzureCredential is flexible enough to adapt to both the development environment and the Azure environment. When running locally, it can retrieve the logged-in Azure user from the environment of your choice (Visual Studio, Visual Studio Code, Azure CLI, or Azure PowerShell). When running in Azure, it retrieves the managed identity. So it's possible to have connectivity to database both at development time and in production. The pattern is as follows:
Instantiate a DefaultAzureCredential from the Azure Identity client library. If you're using a user-assigned identity, specify the client ID of the identity.
Get an access token for Azure Database for PostgreSQL: https://ossrdbms-aad.database.windows.net/.default.
For .NET, get an access token for the managed identity using a client library such as Azure.Identity. Then use the access token as a password to connect to the database. When using the code below, make sure you uncomment the part of the code snippet that corresponds to the authentication type you want to use.
using Azure.Identity;
using Azure.Core;
using Npgsql;
// Uncomment the following lines according to the authentication type.
// For system-assigned identity.
// var sqlServerTokenProvider = new DefaultAzureCredential();
// For user-assigned identity.
// var sqlServerTokenProvider = new DefaultAzureCredential(
// new DefaultAzureCredentialOptions
// {
// ManagedIdentityClientId = Environment.GetEnvironmentVariable("AZURE_POSTGRESQL_CLIENTID");
// }
// );
// Acquire the access token.
AccessToken accessToken = await sqlServerTokenProvider.GetTokenAsync(
new TokenRequestContext(scopes: new string[]
{
"https://ossrdbms-aad.database.windows.net/.default"
}));
// Combine the token with the connection string from the environment variables provided by Service Connector.
string connectionString =
$"{Environment.GetEnvironmentVariable("AZURE_POSTGRESQL_CONNECTIONSTRING")};Password={accessToken.Token}";
// Establish the connection.
using (var connection = new NpgsqlConnection(connectionString))
{
Console.WriteLine("Opening connection using access token...");
connection.Open();
}
Add the following dependencies in your pom.xml file:
Authenticate with an access token from the azure-identity library and use the token as password. Get the connection information from the environment variables added by Service Connector. When using the code below, make sure you uncomment the part of the code snippet that corresponds to the authentication type you want to use.
from azure.identity import DefaultAzureCredential
import psycopg2
# Uncomment the following lines according to the authentication type.
# For system-assigned identity.
# cred = DefaultAzureCredential()
# For user-assigned identity.
# managed_identity_client_id = os.getenv('AZURE_POSTGRESQL_CLIENTID')
# cred = ManagedIdentityCredential(client_id=managed_identity_client_id)
# Acquire the access token
accessToken = cred.get_token('https://ossrdbms-aad.database.windows.net/.default')
# Combine the token with the connection string from the environment variables added by Service Connector to establish the connection.
conn_string = os.getenv('AZURE_POSTGRESQL_CONNECTIONSTRING')
conn = psycopg2.connect(conn_string + ' password=' + accessToken.token)
For more information, see the following resources:
In code, get the access token via @azure/identity and PostgreSQL connection information from environment variables added by Service Connector service. Combine them to establish the connection. When using the code below, make sure you uncomment the part of the code snippet that corresponds to the authentication type you want to use.
import { DefaultAzureCredential, ClientSecretCredential } from "@azure/identity";
const { Client } = require('pg');
// Uncomment the following lines according to the authentication type.
// For system-assigned identity.
// const credential = new DefaultAzureCredential();
// For user-assigned identity.
// const clientId = process.env.AZURE_POSTGRESQL_CLIENTID;
// const credential = new DefaultAzureCredential({
// managedIdentityClientId: clientId
// });
// Acquire the access token.
var accessToken = await credential.getToken('https://ossrdbms-aad.database.windows.net/.default');
// Use the token and the connection information from the environment variables added by Service Connector to establish the connection.
(async () => {
const client = new Client({
host: process.env.AZURE_POSTGRESQL_HOST,
user: process.env.AZURE_POSTGRESQL_USER,
password: accesstoken.token,
database: process.env.AZURE_POSTGRESQL_DATABASE,
port: Number(process.env.AZURE_POSTGRESQL_PORT) ,
ssl: process.env.AZURE_POSTGRESQL_SSL
});
await client.connect();
await client.end();
})();
This sample code uses DefaultAzureCredential to get a useable token for your Azure database from Microsoft Entra ID and then adds it to the database connection. While you can customize DefaultAzureCredential, it's already versatile by default. It gets a token from the signed-in Microsoft Entra user or from a managed identity, depending on whether you run it locally in your development environment or in App Service.
Without any further changes, your code is ready to be run in Azure. To debug your code locally, however, your develop environment needs a signed-in Microsoft Entra user. In this step, you configure your environment of choice by signing in with your Microsoft Entra user.
Visual Studio for Windows is integrated with Microsoft Entra authentication. To enable development and debugging in Visual Studio, add your Microsoft Entra user in Visual Studio by selecting File > Account Settings from the menu, and select Sign in or Add.
To set the Microsoft Entra user for Azure service authentication, select Tools > Options from the menu, then select Azure Service Authentication > Account Selection. Select the Microsoft Entra user you added and select OK.
Visual Studio for Mac is not integrated with Microsoft Entra authentication. However, the Azure Identity client library that you'll use later can also retrieve tokens from Azure CLI. To enable development and debugging in Visual Studio, install Azure CLI on your local machine.
Sign in to Azure CLI with the following command using your Microsoft Entra user:
az login --allow-no-subscriptions
Visual Studio Code is integrated with Microsoft Entra authentication through the Azure extension. Install the Azure Tools extension in Visual Studio Code.
In Visual Studio Code, in the Activity Bar, select the Azure logo.
In the App Service explorer, select Sign in to Azure... and follow the instructions.
The Azure Identity client library that you'll use later can use tokens from Azure CLI. To enable command-line based development, install Azure CLI on your local machine.
Sign in to Azure with the following command using your Microsoft Entra user:
az login --allow-no-subscriptions
The Azure Identity client library that you'll use later can use tokens from Azure PowerShell. To enable command-line based development, install Azure PowerShell on your local machine.
Sign in to Azure CLI with the following cmdlet using your Microsoft Entra user:
You're now ready to develop and debug your app with the SQL Database as the back end, using Microsoft Entra authentication.
5. Test and publish
Run your code in your dev environment. Your code uses the signed-in Microsoft Entra user in your environment to connect to the back-end database. The user can access the database because it's configured as a Microsoft Entra administrator for the database.
Publish your code to Azure using the preferred publishing method. In App Service, your code uses the app's managed identity to connect to the back-end database.
I get the error Login failed for user '<token-identified principal>'.
The managed identity you're attempting to request a token for is not authorized to access the Azure database.
I made changes to App Service authentication or the associated app registration. Why do I still get the old token?
The back-end services of managed identities also maintain a token cache that updates the token for a target resource only when it expires. If you modify the configuration after trying to get a token with your app, you don't actually get a new token with the updated permissions until the cached token expires. The best way to work around this is to test your changes with a new InPrivate (Edge)/private (Safari)/Incognito (Chrome) window. That way, you're sure to start from a new authenticated session.
How do I add the managed identity to a Microsoft Entra group?
If you want, you can add the identity to an Microsoft Entra group, then grant access to the Microsoft Entra group instead of the identity. For example, the following commands add the managed identity from the previous step to a new group called myAzureSQLDBAccessGroup:
groupid=$(az ad group create --display-name myAzureSQLDBAccessGroup --mail-nickname myAzureSQLDBAccessGroup --query objectId --output tsv)
msiobjectid=$(az webapp identity show --resource-group <group-name> --name <app-name> --query principalId --output tsv)
az ad group member add --group $groupid --member-id $msiobjectid
az ad group member list -g $groupid
To grant database permissions for a Microsoft Entra group, see documentation for the respective database type.
I get the error SSL connection is required. Please specify SSL options and retry.
Connecting to the Azure database requires additional settings and is beyond the scope of this tutorial. For more information, see one of the following links:
I created my app with the Web App + Database template, and now I can't configure a managed identity connection with the Service Connector commands.
Service Connector needs network access to the database in order to grant access for the app identity. When you create a secure-by-default app and database architecture in the Azure portal with the Web App + Database template, the architecture locks down network access to the database and only allows connections from within the virtual network. It's also true for Azure Cloud Shell. However, you can deploy Cloud Shell in the virtual network, then run the Service Connector command in that Cloud Shell.
Next steps
What you learned:
Configure a Microsoft Entra user as an administrator for your Azure database.
Connect to your database as the Microsoft Entra user.
Configure a system-assigned or user-assigned managed identity for an App Service app.
Grant database access to the managed identity.
Connect to the Azure database from your code (.NET Framework 4.8, .NET 6, Node.js, Python, Java) using a managed identity.
Connect to the Azure database from your development environment using the Microsoft Entra user.