Application settings and connection strings in Azure - Commands & Configuration

Introduction

Application settings and connection strings store important information like keys and URLs that your app needs to work. They keep this data separate from your code so you can change settings without changing the app itself.

When you want to keep your database login details safe and separate from your app code.

When you need to change an API key without updating your app's code.

When you want to use different settings for development and production environments.

When you want to quickly update a service URL your app connects to without redeploying.

When you want to manage secrets like passwords securely in Azure App Service.

Commands

This command sets an application setting named MySetting with the value HelloWorld for the Azure web app named example-app. It helps you add or update settings your app uses.

Terminal

az webapp config appsettings set --name example-app --resource-group example-rg --settings MySetting=HelloWorld

Expected Output

{"id":"/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/example-rg/providers/Microsoft.Web/sites/example-app/config/appsettings","name":"appsettings","type":"Microsoft.Web/sites/config","location":"East US","properties":{"MySetting":"HelloWorld"}}

→

--name - Specifies the name of the web app.

→

--resource-group - Specifies the resource group of the web app.

→

--settings - Defines the key-value pairs for application settings.

This command sets a connection string named MyDb for the Azure web app example-app. It stores the database connection details securely for the app to use.

Terminal

az webapp config connection-string set --name example-app --resource-group example-rg --settings MyDb=Server=tcp:myserver.database.windows.net;Database=mydb;User Id=myuser;Password=mypassword; --connection-string-type SQLAzure

Expected Output

{"id":"/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/example-rg/providers/Microsoft.Web/sites/example-app/config/connectionstrings","name":"connectionstrings","type":"Microsoft.Web/sites/config","location":"East US","properties":{"MyDb":"Server=tcp:myserver.database.windows.net;Database=mydb;User Id=myuser;Password=mypassword;"}}

→

--connection-string-type - Specifies the type of database or service the connection string is for.

This command lists all application settings for the web app example-app so you can verify what settings are currently set.

Terminal

az webapp config appsettings list --name example-app --resource-group example-rg

Expected Output

[{"name":"MySetting","value":"HelloWorld"}]

→

--name - Specifies the web app name.

→

--resource-group - Specifies the resource group.

This command lists all connection strings for the web app example-app so you can check the stored connection details.

Terminal

az webapp config connection-string list --name example-app --resource-group example-rg

Expected Output

[{"name":"MyDb","connectionString":"Server=tcp:myserver.database.windows.net;Database=mydb;User Id=myuser;Password=mypassword;","type":"SQLAzure"}]

→

--name - Specifies the web app name.

→

--resource-group - Specifies the resource group.

Key Concept

If you remember nothing else from this pattern, remember: keep your app settings and connection strings separate from your code so you can update them safely without changing your app.

Common Mistakes

Putting sensitive information like passwords directly in the app code.

This makes it hard to change secrets and risks exposing them if the code is shared.

Use Azure App Service application settings and connection strings to store secrets securely.

Not specifying the correct connection string type when setting connection strings.

Azure may not handle the connection string properly, causing connection failures.

Always use the --connection-string-type flag with the correct type like SQLAzure or MySQL.

Forgetting to verify settings after setting them.

You might think the setting was applied but it could have failed or been mistyped.

Run the list commands to confirm your settings and connection strings are set correctly.

Summary

Use 'az webapp config appsettings set' to add or update app settings for your Azure web app.

Use 'az webapp config connection-string set' to securely store database connection details.

Verify your settings with 'az webapp config appsettings list' and connection strings with 'az webapp config connection-string list'.

Practice

1. What is the main purpose of using Application settings in an Azure App Service?

easy

A. To store configuration values separately from the app code

B. To write application code directly in the Azure portal

C. To deploy the app to multiple regions automatically

D. To monitor app performance metrics

Solution

1. Step 1: Understand what application settings are

   Application settings hold configuration values like API keys or feature flags outside the app code.

2. Step 2: Identify the benefit of separation

   Separating settings allows changing them without redeploying or modifying the app code.

3. Final Answer:

   To store configuration values separately from the app code -> Option A

4. Quick Check:

   Application settings separate config from code [OK]

Hint: Settings keep config outside code for easy updates [OK]

Common Mistakes:

• Confusing settings with code deployment
• Thinking settings are for monitoring
• Assuming settings are for writing code

2. Which Azure CLI command correctly sets an application setting named MySetting with value Value123 for an App Service named MyApp?

easy

A. az webapp config appsettings set --name MyApp --resource-group MyGroup --settings MySetting=Value123

B. az webapp create appsettings add --name MyApp --settings MySetting=Value123

C. az appservice config set --app MyApp --setting MySetting=Value123

D. az webapp config connection-string set --name MyApp --settings MySetting=Value123

Solution

1. Step 1: Identify the correct Azure CLI command for app settings

   The command to set app settings is az webapp config appsettings set with parameters for app name, resource group, and settings.

2. Step 2: Check the syntax for setting a key-value pair

   The settings parameter uses key=value format, here MySetting=Value123.

3. Final Answer:

   az webapp config appsettings set --name MyApp --resource-group MyGroup --settings MySetting=Value123 -> Option A

4. Quick Check:

   Use az webapp config appsettings set with key=value [OK]

Hint: Use 'az webapp config appsettings set' with key=value [OK]

Common Mistakes:

• Using wrong command verbs like create or add
• Confusing app settings with connection strings
• Missing resource group parameter

3. Given this Azure CLI command output after setting a connection string:

{"id": "/subscriptions/123/resourceGroups/MyGroup/providers/Microsoft.Web/sites/MyApp/config/connectionstrings", "name": "MyApp", "connectionStrings": [{"name": "DbConn", "connectionString": "Server=myserver;Database=mydb;", "type": "SQLAzure"}]}

What will the app receive when accessing the connection string DbConn?

medium

A. An empty string because connection strings are not set this way

B. An error because the connection string type is missing

C. The string 'Server=myserver;Database=mydb;' as the connection string value

D. The connection string encrypted and unreadable

Solution

1. Step 1: Understand the connection string format in Azure

   The output shows a connection string named 'DbConn' with a valid connection string value and type 'SQLAzure'.

2. Step 2: Determine what the app receives

   The app reads the connection string value as plain text 'Server=myserver;Database=mydb;' to connect to the database.

3. Final Answer:

   The string 'Server=myserver;Database=mydb;' as the connection string value -> Option C

4. Quick Check:

   Connection strings provide plain text values to apps [OK]

Hint: Connection strings deliver plain text values to apps [OK]

Common Mistakes:

• Assuming connection strings are encrypted automatically
• Thinking type field is mandatory for usage
• Believing connection strings are empty if not set in code

4. You run this Azure CLI command to update an app setting:
az webapp config appsettings set --name MyApp --resource-group MyGroup --settings MySetting
But it fails with an error. What is the likely cause?

medium

A. The resource group name is incorrect

B. The setting value is missing after the key 'MySetting'

C. The app name 'MyApp' does not exist

D. The command should use 'appsettings add' instead of 'set'

Solution

1. Step 1: Check the command syntax for setting app settings

   The --settings parameter requires key=value pairs, but only 'MySetting' (key) is provided without a value.

2. Step 2: Identify the error cause

   Missing value after the key causes the command to fail due to invalid syntax.

3. Final Answer:

   The setting value is missing after the key 'MySetting' -> Option B

4. Quick Check:

   App settings need key=value pairs [OK]

Hint: Always provide key=value pairs for app settings [OK]

Common Mistakes:

• Omitting the value after the key
• Assuming 'set' is wrong command
• Ignoring error messages about syntax

5. You want to securely update a database connection string in your Azure App Service without restarting the app. Which approach is best?

hard

A. Edit the connection string directly in the app code and redeploy

B. Set the connection string as an environment variable in your local machine

C. Store the connection string in a public GitHub repo and pull it at runtime

D. Use Azure CLI to update the connection string via az webapp config connection-string set and enable slot settings

Solution

1. Step 1: Understand secure connection string management

   Updating connection strings via Azure CLI keeps secrets out of code and allows live updates.

2. Step 2: Use slot settings to avoid app restarts

   Enabling slot settings for connection strings prevents app restarts and keeps settings sticky to deployment slots.

3. Final Answer:

   Use Azure CLI to update the connection string via az webapp config connection-string set and enable slot settings -> Option D

4. Quick Check:

   Use CLI and slot settings for secure live updates [OK]

Hint: Update connection strings via CLI with slot settings [OK]

Common Mistakes:

• Changing connection strings in code causing redeploy
• Exposing secrets in public repos
• Setting local env vars which don't affect Azure app