Bicep File Structure

A Bicep file is composed of several key elements, each serving a distinct purpose in resource deployment:

Metadata (metadata): Provides supplementary information about the Bicep file, such as descriptions or versioning details.
Target Scope (targetScope): Defines the deployment scope, indicating whether the resources are deployed at the resource group, subscription, management group, or tenant level.
Parameters (param): Allow customization of deployments by accepting input values during deployment.
Variables (var): Store computed values or constants to simplify expressions within the Bicep file.
Resources (resource): Declare the Azure resources to be deployed, specifying their types, properties, and configurations.
Modules (module): Encapsulate reusable Bicep code, enabling modularization and better organization of complex deployments.
Outputs (output): Define values to be returned after deployment, which can be used for subsequent operations or referenced in other deployments.

Bicep Syntax Elements

Metadata

The metadata keyword is used to add descriptive information to your Bicep file. This can include details like the purpose of the file or version information.

metadata description = 'Deploys a storage account and a web app'

Target Scope

The targetScope keyword specifies the level at which the deployment is executed. The default scope is resourceGroup. Other valid scopes include subscription, managementGroup, and tenant.

targetScope = 'resourceGroup'

Parameters

Parameters allow you to pass values into the Bicep file during deployment, making your templates more flexible and reusable.

@description('The prefix to use for the storage account name.')
@minLength(3)
@maxLength(11)
param storagePrefix string

In this example, the storagePrefix parameter is defined with a description and length constraints.

Variables

Variables store values that are derived from parameters or computed expressions, simplifying complex expressions within your Bicep file.

var uniqueStorageName = '${storagePrefix}${uniqueString(resourceGroup().id)}'

Here, uniqueStorageName combines the storagePrefix parameter with a unique string based on the resource group ID.

Resources

The resource keyword is used to declare Azure resources to be deployed. Each resource declaration includes a symbolic name, resource type with API version, and a set of properties.

resource storageAccount 'Microsoft.Storage/storageAccounts@2023-04-01' = {
  name: uniqueStorageName
  location: location
  sku: {
    name: storageSKU
  }
  kind: 'StorageV2'
  properties: {
    supportsHttpsTrafficOnly: true
  }
}

This example defines a storage account resource with specific configurations.

Modules

Modules enable you to encapsulate and reuse Bicep code across different deployments, promoting modularity and maintainability.

bicepCopyEditmodule webModule './webApp.bicep' = {
  name: 'webDeploy'
  params: {
    skuName: 'S1'
    location: location
  }
}

In this snippet, the webModule module is invoked, passing parameters to configure its deployment.

Outputs

Outputs define values that are returned after the deployment is complete, which can be useful for retrieving resource properties or passing information to other deployments.

output storageEndpoint object = storageAccount.properties.primaryEndpoints

This output returns the primary endpoints of the deployed storage account.

Decorators

Decorators in Bicep are annotations that provide additional information or constraints for parameters, variables, resources, modules, outputs, functions, and user-defined data types. They are prefixed with the @ symbol and placed above the declaration they modify.

Common decorators include:

@description(): Adds a description to the element.
@minLength(): Specifies the minimum length for strings or arrays.
@maxLength(): Specifies the maximum length for strings or arrays.
@allowed(): Defines an allowed set of values for a parameter.
@secure(): Marks a parameter as secure, ensuring its value isn't exposed in deployment outputs or logs.

For a comprehensive list of decorators and their usage, refer to the Bicep file structure and syntax documentation.

Last updated 4 days ago

resource storageAccount 'Microsoft.Storage/storageAccounts@2023-04-01' = { name: uniqueStorageName location: location sku: { name: storageSKU } kind: 'StorageV2' properties: { supportsHttpsTrafficOnly: true } }