Introduction

A very simple Multi-Region design for an application following Command Query Responsibility Separation (CQRS) principles in Azure. In other words, the world's most expensive random number generator....

Prerequisites

• A Posix compliant System. It could be one of the following:
  • Github CodeSpaces
  • Azure Linux VM - Standard_B1s VM will work ($18/month)
  • Windows 11 with Windows Subsystem for Linux
• dotnet 8 - The .NET Platform
• Golang - The Go Programming Language
• Visual Studio Code or equivalent - A lightweight code editor
• Docker - The Docker Desktop to build/push containers
• Azure CLI - A tool for managing Azure resources
• PowerShell - The PowerShell Core for running scripts
• git - The source control tool
• Taskfile - A task runner for the shell
• Terraform - A tool for building Azure infrastructure and infrastructure as code
• If exposing application externally then a public domain that you can create DNS records
• Required Certificates

Notes

The documentation will use bjd.demo throughout as the root domain. This can be replaced with your own domain

Codespaces

You can use the following link to launch a Codespaces configured for this project:

Public DNS Records:

• The following DNS records are required for the application to work correctly. These are used for the application to be accessed externally. The following records are required:

  Name	Usage	DNS Record Type	IP Address
  api.bjd.demo	Azure Front Door	CNAME	Front Door URL>
  westus.api.bjd.demo	App Gateway	A	App Gateway IP Address in West US
  eastus.api.bjd.demo	App Gateway	A	App Gateway IP Address in East US

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Task

• The deployment of this application has been automated using Taskfile. This was done instead of using a CI/CD pipeline to make it easier to understand the deployment process.
• Of course, the application can be deployed manually
• The Taskfile is a simple way to run commands and scripts in a consistent manner.
• The Taskfile definition is located in the root of the repository
• The Task file declares the default values that can be updated to suit specific requirements:

Taskfile Variables

Name	Usage	Location	Required	Default or Example Value
TITLE	Value used in Azure Tags	taskfile.yaml	Yes	CQRS Multi-region Pattern in Azure
DEFAULT_REGIONS	Default region to deploy to	taskfile.yaml	Yes	["westus3"]
DOMAIN_ROOT	Default root domain used for all URLs & certs	taskfile.yaml	Yes	bjd.demo
EXTERNAL_DEPLOYMENT	Will this deployment deploy external components	taskfile.yaml	Yes	false
USE_REDIS_CACHE	Caches results into Azure Redis Cache	taskfile.yaml	No	false
DEPLOYMENT_TYPE	Will this deployment deploy to multiple regions	taskfile.yaml	Yes	single (multiregion or single are valid options)
APIM_PFX_CERT_PATH	Path to the APIM PFX certificate	.env	External Only	./certs/apim.pfx
APIM_PFX_CERT_PASSWORD	Password for the APIM PFX certificate	.env	External Only
APP_GW_PFX_CERT_PATH	Path to the App Gateway PFX certificate	.env	External Only	./certs/appgw.pfx
APP_GW_PFX_CERT_PASSWORD	Password for the App Gateway PFX certificate	.env	External Only
FRONTDOOR_URL	The Custom URL for the Azure Front Door	.env	External Only	api.bjd.demo
APP_GW_URLS	The URLs for the App Gateways	.env	External Only	["westus.api.bjd.demo"]
APIM_URLS	The Urls for the APIM Gateways	.env	External Only	["westus.apim.bjd.demo"]

Task Commands

• Running the task command without any options will run the default command. This will list all the available tasks.
  • task init : Initialized Terraform modules
  • task up : Builds complete environment
  • task down : Destroys all Azure resources and cleans up Terraform
  • task apply : Applies the Terraform configuration for the core components
  • task external : Applies ARM templates for external components
  • task apim : Deploys Azure API Management
  • task appgw : Deploys Azure Application Gateway
  • task frontdoor : Deploys Azure Front Door
  • task build : Builds containers and pushes to Azure Container Registry
  • task deploy : Creates application components and deploy the application code
  • task ui : Deploys Blazor UI components to Azure Static Web Apps
  • task validate : Creates a tunnel to the utils container app to test internal components

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Roadmap

• Moved to Taskfile for deployments instead of script
• Validate certificates naming standards
• General rev updates of TF resources
• General rev updates of ARM template resources
• Update naming standards
• Moved to Managed Redis instead of Azure Cache for Redis
• Code (and modules) updated to latest versions
• Event Processor Function Code updated to Managed Identities for Event Hubs, Functions Runtime/Storage and Redis
• Change Feed Processor Function Code updated to Managed Identities for Event Hubs, Functions Runtime/Storage
• API updated to Managed Identities for Event Hubs, App Insights and Redis
• Gracefully handle connection issues on API startup - non-persistent mode
• Review new APIM v2 features and platform for additional updates
• Update documentation
• Review AppGateway and Front Door configurations for additional updates

Setup

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