Application settings and connection strings in Azure - Step-by-Step Execution

Process Flow - Application settings and connection strings

Define App Settings

↓

Define Connection Strings

↓

Deploy to Azure App Service

↓

App Service Reads Settings

↓

App Uses Settings & Connections

↓

App Runs with Configured Values

This flow shows how application settings and connection strings are defined, deployed, and used by an Azure App Service.

Execution Sample

Azure

appSettings:
  - name: "ENVIRONMENT"
    value: "Production"
connectionStrings:
  - name: "MyDb"
    connectionString: "Server=myserver;Database=mydb;User Id=admin;Password=pass;"

Defines an app setting and a connection string that the Azure App Service will use at runtime.

Process Table

Step	Action	Configuration State	App Service Behavior
1	Define app setting ENVIRONMENT=Production	App settings: {ENVIRONMENT: 'Production'}	No app interaction yet
2	Define connection string MyDb	Connection strings: {MyDb: 'Server=myserver;Database=mydb;User Id=admin;Password=pass;'}	No app interaction yet
3	Deploy settings to Azure App Service	App settings and connection strings stored in Azure	App service ready to read settings
4	App Service starts and reads ENVIRONMENT	Settings remain unchanged	App environment variable ENVIRONMENT='Production'
5	App Service reads connection string MyDb	Connection strings unchanged	App connects to database using MyDb string
6	App runs using these settings	Settings stable	App behaves according to ENVIRONMENT and DB connection
7	End	No changes	App runs successfully with configured settings

💡 App service has loaded all settings and connection strings; app runs with these values

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	Final
AppSettings	{}	{ENVIRONMENT: 'Production'}	{ENVIRONMENT: 'Production'}	{ENVIRONMENT: 'Production'}	{ENVIRONMENT: 'Production'}	{ENVIRONMENT: 'Production'}	{ENVIRONMENT: 'Production'}
ConnectionStrings	{}	{}	{MyDb: 'Server=myserver;Database=mydb;User Id=admin;Password=pass;'}	{MyDb: 'Server=myserver;Database=mydb;User Id=admin;Password=pass;'}	{MyDb: 'Server=myserver;Database=mydb;User Id=admin;Password=pass;'}	{MyDb: 'Server=myserver;Database=mydb;User Id=admin;Password=pass;'}	{MyDb: 'Server=myserver;Database=mydb;User Id=admin;Password=pass;'}
AppEnvironmentVariable	undefined	undefined	undefined	'Production'	'Production'	'Production'	'Production'
AppDbConnection	undefined	undefined	undefined	undefined	undefined	Connected	Connected

Key Moments - 3 Insights

Why does the app read the settings only after deployment?

Because the app service loads the configuration from Azure only when it starts or restarts, as shown in steps 3 and 4 of the execution_table.

Are app settings and connection strings stored inside the app code?

No, they are stored separately in Azure App Service configuration, allowing changes without redeploying the app, as seen in step 3.

What happens if the connection string is incorrect?

The app will fail to connect to the database at step 5, causing runtime errors, but the settings themselves remain unchanged.

Visual Quiz - 3 Questions

Look at the execution_table at step 4, what value does the app environment variable ENVIRONMENT have?

A 'Production'

B 'Development'

C undefined

D null

💡 Hint

Check the 'App Environment Variable' column in variable_tracker after step 4.

At which step does the app service first have access to the connection string MyDb?

A Step 2

B Step 3

C Step 5

D Step 6

💡 Hint

Look at the 'Configuration State' column in execution_table where connection strings are stored in Azure.

If the app setting ENVIRONMENT was changed to 'Staging' before deployment, how would the variable_tracker change after step 4?

A 'Production'

B undefined

C 'Staging'

D null

💡 Hint

Refer to the 'AppEnvironmentVariable' row in variable_tracker and imagine the new value after step 4.

Concept Snapshot

Application settings and connection strings are key-value pairs stored in Azure App Service configuration.
They are defined before deployment and loaded by the app at runtime.
Settings can be changed without redeploying the app.
Connection strings provide secure database access.
App reads these values on start and uses them during execution.

Full Transcript

This visual execution shows how application settings and connection strings are defined, deployed, and used in Azure App Service. First, app settings like ENVIRONMENT and connection strings like MyDb are defined. Then, these configurations are deployed to Azure. When the app service starts, it reads these settings and connection strings from its configuration store. The app environment variable ENVIRONMENT is set to 'Production', and the app connects to the database using the MyDb connection string. The app then runs using these configured values. This separation allows changing settings without redeploying the app. The execution table and variable tracker illustrate each step and how variables change. Key moments clarify common confusions about when and where settings are loaded and stored. The quiz tests understanding of these steps and variable states.

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