Bicep syntax and modules in Azure - Mini Project: Build & Apply

Bicep Syntax and Modules

📖 Scenario: You are working on an Azure cloud project. You want to organize your infrastructure code using Bicep modules. This helps keep your code clean and reusable.

🎯 Goal: Build a simple Bicep project that defines a storage account in a module and then uses that module in the main Bicep file.

📋 What You'll Learn

Create a Bicep module file named storage.bicep that defines an Azure Storage Account resource.

Create a main Bicep file named main.bicep that calls the storage.bicep module.

Pass the storage account name as a parameter from main.bicep to the module.

Use correct Bicep syntax for module declaration and parameter passing.

💡 Why This Matters

🌍 Real World

Using Bicep modules helps cloud engineers organize and reuse infrastructure code efficiently in Azure deployments.

💼 Career

Understanding Bicep syntax and modules is essential for Azure infrastructure as code roles and DevOps engineers working with Azure Resource Manager.

1

Create the storage.bicep module

Create a Bicep file named storage.bicep. Inside it, declare a parameter called storageAccountName of type string. Then define a resource named storageAccount of type Microsoft.Storage/storageAccounts@2022-09-01 with the name set to storageAccountName, location set to resourceGroup().location, and sku name set to Standard_LRS. Use kind as StorageV2.

Azure

# Your code here to create storage.bicep module with parameter and storage account resource

Hint

Remember to declare the parameter first, then define the resource using the parameter for the name.

2

Create the main.bicep file with a parameter

Create a Bicep file named main.bicep. Declare a parameter called storageName of type string. This will hold the storage account name to pass to the module.

Azure

param storageName string
# Your code here to declare storageName parameter in main.bicep

Hint

Just declare a parameter named storageName of type string at the top of main.bicep.

3

Add the module call in main.bicep

In main.bicep, add a module declaration named storageModule that references the storage.bicep file. Pass the storageName parameter to the module's storageAccountName parameter.

Azure

param storageName string

module storageModule 'storage.bicep' = {
  name: 'storageModule'
  params: {
    // Your code here to pass storageName to storageAccountName
  }
}

Hint

Use module storageModule 'storage.bicep' = { ... } and inside params, map storageAccountName to storageName.

4

Clean up main.bicep by removing unused code

Remove the direct resource storageAccount declaration and the param storageAccountName from main.bicep. Keep only the param storageName and the module declaration.

Azure

param storageName string

module storageModule 'storage.bicep' = {
  name: 'storageModule'
  params: {
    storageAccountName: storageName
  }
}
# Remove the resource and extra parameter below

Hint

Keep only the parameter and module call in main.bicep. Remove the resource and extra parameter.

Practice

1. What is the main purpose of a module in Bicep?

easy

A. To reuse and organize infrastructure code by calling other Bicep files

B. To define variables inside a Bicep file

C. To store output values only

D. To create a new Azure subscription

Solution

1. Step 1: Understand what a module does

   A module in Bicep is a way to include and reuse other Bicep files, helping organize code.

2. Step 2: Compare options to the definition

   Only To reuse and organize infrastructure code by calling other Bicep files correctly describes modules as reusable code blocks. Variables and outputs are different concepts, and creating subscriptions is unrelated.

3. Final Answer:

   To reuse and organize infrastructure code by calling other Bicep files -> Option A

4. Quick Check:

   Module = reusable code block [OK]

Hint: Modules call other files to reuse code easily [OK]

Common Mistakes:

• Confusing modules with variables
• Thinking modules only store outputs
• Believing modules create Azure subscriptions

2. Which of the following is the correct syntax to declare a module in Bicep?

easy

A. module myModule = 'module.bicep' {}

B. module myModule 'module.bicep' = {}

C. module 'myModule' = module.bicep {}

D. module 'myModule' 'module.bicep' {}

Solution

1. Step 1: Recall module declaration syntax

   The correct syntax is: module <name> '<path>' = {}.

2. Step 2: Match options to syntax

   module myModule 'module.bicep' = {} matches the correct syntax exactly. Other options have misplaced quotes or assignment operators.

3. Final Answer:

   module myModule 'module.bicep' = {} -> Option B

4. Quick Check:

   module name 'file' = {} [OK]

Hint: Use: module name 'file.bicep' = {} [OK]

Common Mistakes:

• Putting quotes around the module name
• Using = before the file path
• Omitting the equals sign

3. Given this Bicep code snippet, what will be the output value of moduleOutput?

module storageModule 'storage.bicep' = {
  name: 'storage1'
}

output moduleOutput string = storageModule.outputs.storageAccountName

medium

A. An error because outputs cannot be accessed from modules

B. The module file path 'storage.bicep'

C. The name of the storage account defined inside storage.bicep

D. The string 'storage1'

Solution

1. Step 1: Understand module outputs

   Modules can expose outputs which can be accessed using moduleName.outputs.outputName.

2. Step 2: Analyze the code snippet

   The output moduleOutput gets the value of storageAccountName from the module's outputs, which is the storage account name defined inside storage.bicep.

3. Final Answer:

   The name of the storage account defined inside storage.bicep -> Option C

4. Quick Check:

   module.outputs = module data access [OK]

Hint: Access module outputs with moduleName.outputs.outputName [OK]

Common Mistakes:

• Thinking outputs can't be accessed from modules
• Confusing module name with file path
• Assuming output is the module instance name

4. Identify the error in this Bicep module usage:

module webAppModule 'webapp.bicep' = {
  name: 'webApp1'
  params: {
    location: 'eastus'
  }
}

medium

A. Incorrect keyword 'params' should be 'parameters'

B. Module name cannot contain numbers

C. Module file path must be absolute

D. Missing equals sign after 'name'

Solution

1. Step 1: Check parameter passing syntax in modules

   In Bicep, module parameters can be passed directly as properties (e.g., location: 'eastus') or nested under parameters: { ... }. params is not a valid keyword.

2. Step 2: Identify the error

   The code uses invalid params:, which should be parameters: for nested parameters.

3. Final Answer:

   Incorrect keyword 'params' should be 'parameters' -> Option A

4. Quick Check:

   parameters: { } for nested params [OK]

Hint: Use 'parameters:' not 'params' for nested params [OK]

Common Mistakes:

• Using 'params' instead of 'parameters'
• Thinking module names cannot contain numbers
• Believing file paths must be absolute

5. You want to create a reusable Bicep module for a virtual network that accepts a parameter for the address prefix and outputs the subnet ID. How should you define the module's parameter and output to follow best practices?

hard

A. Declare the address prefix as an output and subnet ID as a parameter

B. Use a variable for address prefix and no output since subnet ID is internal

C. Hardcode the address prefix and output the subnet name instead of ID

D. Declare a param addressPrefix string and an output subnetId string in the module file

Solution

1. Step 1: Define parameters for input values

   Best practice is to declare inputs as parameters so the module is flexible. Here, param addressPrefix string allows passing different address prefixes.

2. Step 2: Define outputs for important results

   Outputs share useful info back to the caller. The subnet ID is important to output as output subnetId string.

3. Final Answer:

   Declare a param addressPrefix string and an output subnetId string in the module file -> Option D

4. Quick Check:

   Parameters input, outputs share results [OK]

Hint: Use param for inputs, output for results [OK]

Common Mistakes:

• Using variables instead of parameters for inputs
• Not outputting needed resource IDs
• Mixing parameters and outputs roles