DEV Community: Yency Christopher

Azure Service Bus

Yency Christopher — Mon, 16 Mar 2026 23:02:26 +0000

Azure Service Bus is a fully managed cloud messaging service in Microsoft Azure that acts as a reliable intermediary between applications and services. Think of it as a post office in the cloud, senders drop off messages, and receivers pick them up when ready, with no need for both parties to be online at the same time.

It supports two core messaging patterns: queues (point-to-point, one sender → one receiver) and topics/subscriptions (publish-subscribe, one sender → multiple receivers). Messages are stored durably until processed, making it ideal for decoupling distributed systems.

Real-world examples

E-commerce order processing
When a customer places an order, the Order Service drops a message into a queue. The Payment Service picks it up independently. If payment processing is slow or briefly down, orders aren't lost they wait in the queue.
Inventory updates (pub-sub)
When stock changes, the Inventory Service publishes a message to a topic. Three separate subscribers receive it simultaneously: a Warehouse app (to pick items), an Analytics service (to update dashboards), and an Email service (to notify customers). None of them needs to know about each other.
Microservices decoupling
In a large banking app, the Loan Service sends an approval message to the Service Bus. Downstream services like Document Generation, Notifications, and Auditing each consume that event independently — if one crashes, the others keep running.

Configuration Example

Let's make the configuration using:

Terraform # variables.tf variable "resource_group_name" { description = "Your existing RG name" type = string }

variable "location" {
description = "Azure region"
type = string
default = "eastus"
}

variable "namespace_name" {
description = "Service Bus namespace name (globally unique)"
type = string
}

main.tf

terraform {
required_providers {
azurerm = {
source = "hashicorp/azurerm"
version = "~> 3.0"
}
}
}

provider "azurerm" {
features {}
}

Reference your EXISTING resource group (don't create a new one)

data "azurerm_resource_group" "existing" {
name = var.resource_group_name
}

Service Bus Namespace

resource "azurerm_servicebus_namespace" "sb_namespace" {
name = var.namespace_name
location = data.azurerm_resource_group.existing.location
resource_group_name = data.azurerm_resource_group.existing.name
sku = "Standard" # Standard tier required for Topics

tags = {
environment = "lab"
source = "terraform"
}
}

Topic

resource "azurerm_servicebus_topic" "sb_topic" {
name = "lab-topic"
namespace_id = azurerm_servicebus_namespace.sb_namespace.id

enable_partitioning = true
}

Subscription

resource "azurerm_servicebus_subscription" "sb_subscription" {
name = "lab-subscription"
topic_id = azurerm_servicebus_topic.sb_topic.id
max_delivery_count = 10
}

terraform.tfvars

resource_group_name = "your-existing-rg-name"
namespace_name = "sb-whizlab-namespace" # must be globally unique

Deploy:
terraform init
terraform plan
terraform apply

Azure PowerShell ── Variables ────────────────────────────────────────────────── $ResourceGroupName = "your-existing-rg-name" # Your existing RG $NamespaceName = "sb-whizlab-namespace" # Globally unique $TopicName = "lab-topic" $SubscriptionName = "lab-subscription"

── Login (skip if already authenticated) ──────────────────────
Connect-AzAccount

── Get existing RG to inherit location ────────────────────────
$rg = Get-AzResourceGroup -Name $ResourceGroupName
$Location = $rg.Location

── Create Service Bus Namespace ───────────────────────────────
New-AzServiceBusNamespace -ResourceGroupName $ResourceGroupName
-Name $NamespaceName -Location $Location
-SkuName "Standard"

── Create Topic ───────────────────────────────────────────────
New-AzServiceBusTopic -ResourceGroupName $ResourceGroupName
-NamespaceName $NamespaceName -Name $TopicName
-EnablePartitioning $true

── Create Subscription ────────────────────────────────────────
New-AzServiceBusSubscription -ResourceGroupName $ResourceGroupName
-NamespaceName $NamespaceName -TopicName $TopicName
-Name $SubscriptionName `
-MaxDeliveryCount 10

── Verify ─────────────────────────────────────────────────────

Write-Host "`n✅ Resources created:" -ForegroundColor Green
Get-AzServiceBusNamespace -ResourceGroupName $ResourceGroupName -Name $NamespaceName |
Select-Object Name, Location, Sku, ProvisioningState

Terraform Module Troubleshooting Guide

Yency Christopher — Wed, 24 Dec 2025 01:14:54 +0000

Common Error: "Unsupported argument" or "Unsupported attribute."

Symptoms

Error: An argument named "variable_name" is not expected here
Error: This object does not have an attribute named "output_name"
These errors occur even when variables/outputs appear to be correctly defined

Root Causes & Solutions
1. Stale Terraform Module Cache (Most Common)
When you modify module variables or outputs, Terraform may use cached information.

Solution:

When to use: After ANY changes to:

Module variables (variables.tf)
Module outputs (outputs.tf)
Module source paths

2. Empty or Corrupted Files (Critical Issue)
Files may appear in your directory but contain 0 bytes of data.
How to check:

Look for files with Length: 0 or 0 bytes.
Solution: Recreate the file using command line to ensure it saves:

3. Missing Variable Definitions
Error indicates a variable that doesn't exist in the module's variables.tf.
Solution: Add the missing variable to modules/module_name/variables.tf:

Then clear cache and reinitialize (see Solution #1).

4. Missing Output Definitions
Module doesn't expose the output being referenced.
Solution: Add the output to modules/module_name/outputs.tf:

output "output_name" {
  description = "Description"
  value       = azurerm_resource.resource_name.id
}

Then clear cache and reinitialize.

Diagnostic Workflow
Step 1: Verify File Structure

Check for:

All required files exist
No files with 0 bytes
Correct directory structure

Step 2: Verify File Contents

Step 3: Clear Cache and Reinitialize

Step 4: Check Terraform Version

Example variables.tf:

variable "rg_name" {
  description = "Resource group name"
  type        = string
}

variable "location" {
  description = "Azure region"
  type        = string
}

Example outputs.tf:

output "resource_id" {
  description = "ID of the created resource"
  value       = azurerm_resource.name.id
}

Example module call in root main.tf:

module "example" {
  source   = "./modules/module_name"
  rg_name  = "my-rg"
  location = "eastus"
}

# Reference module output
resource "other_resource" "example" {
  dependency_id = module.example.resource_id
}

Common Mistakes to Avoid
❌ Don't:

Edit files without saving (Ctrl+S in VSCode)
Forget to run terraform init after module changes
Use module outputs that aren't defined in outputs.tf
Pass variables that aren't defined in variables.tf

✅ Do:

Always verify files saved correctly (check file size)
Clear .terraform cache after module modifications
Use terraform fmt to format code
Use terraform validate to catch errors early
Keep module interface (variables/outputs) stable

Quick Reference Commands

When All Else Fails

1.Start fresh:

2. Validate each module individually: