Azure Bicep

Name: bicep
Rating: 92
Author: Tyler-R-Kendrick

Overview

Bicep is Azure's domain-specific language for deploying Azure resources declaratively. It compiles to ARM JSON but provides a cleaner syntax with type safety, modules, and IDE support. Bicep is the recommended replacement for authoring ARM templates directly.

Basic Template

bicep

@description('The Azure region for all resources')
param location string = resourceGroup().location

@allowed(['dev', 'staging', 'prod'])
param environment string = 'dev'

resource storageAccount 'Microsoft.Storage/storageAccounts@2023-01-01' = {
  name: 'st${uniqueString(resourceGroup().id)}${environment}'
  location: location
  sku: {
    name: 'Standard_LRS'
  }
  kind: 'StorageV2'
  properties: {
    minimumTlsVersion: 'TLS1_2'
    supportsHttpsTrafficOnly: true
  }
}

resource appServicePlan 'Microsoft.Web/serverfarms@2023-01-01' = {
  name: 'asp-${environment}'
  location: location
  sku: {
    name: environment == 'prod' ? 'P1v3' : 'B1'
  }
}

resource webApp 'Microsoft.Web/sites@2023-01-01' = {
  name: 'app-${environment}-${uniqueString(resourceGroup().id)}'
  location: location
  properties: {
    serverFarmId: appServicePlan.id
    siteConfig: {
      minTlsVersion: '1.2'
    }
  }
}

output webAppUrl string = 'https://${webApp.properties.defaultHostName}'
output storageAccountId string = storageAccount.id

Modules

Reusable components in separate .bicep files:

bicep

// modules/storage.bicep
param name string
param location string
param sku string = 'Standard_LRS'

resource storage 'Microsoft.Storage/storageAccounts@2023-01-01' = {
  name: name
  location: location
  sku: { name: sku }
  kind: 'StorageV2'
}

output id string = storage.id
output name string = storage.name

Consume in the main template:

bicep

module storage 'modules/storage.bicep' = {
  name: 'storageDeployment'
  params: {
    name: 'stmyapp${environment}'
    location: location
    sku: environment == 'prod' ? 'Standard_GRS' : 'Standard_LRS'
  }
}

Deployment

bash

# Deploy to a resource group
az deployment group create \
  --resource-group my-rg \
  --template-file main.bicep \
  --parameters environment=prod

# What-if (preview changes)
az deployment group what-if \
  --resource-group my-rg \
  --template-file main.bicep

# Deploy to subscription scope
az deployment sub create \
  --location eastus \
  --template-file main.bicep

Key Features

Feature	Syntax
Parameters	`param name string` with decorators (`@allowed`, `@minLength`)
Variables	`var name = expression`
Resources	`resource sym 'type@version' = { ... }`
Modules	`module sym 'path.bicep' = { params: {} }`
Outputs	`output name type = value`
Loops	`[for item in list: { ... }]`
Conditions	`if (condition) { ... }` or ternary `condition ? a : b`
Existing resources	`resource sym 'type@version' existing = { name: '...' }`

Best Practices

•Always use what-if to preview changes before deploying.
•Use modules to break large templates into reusable, testable components.
•Use parameter decorators (@allowed, @minLength, @description) for validation and documentation.
•Reference existing resources with the existing keyword instead of hardcoding resource IDs.
•Use uniqueString(resourceGroup().id) for globally unique names (storage accounts, web apps).
•Pin API versions on resources for predictable behavior.
•Use Bicep instead of ARM JSON — it compiles to identical output with better readability.