Tutorial: Deploy a background processing application with Azure Container Apps

Article
08/12/2024

Using Azure Container Apps allows you to deploy applications without requiring the exposure of public endpoints. By using Container Apps scale rules, the application can scale out and in based on the Azure Storage queue length. When there are no messages on the queue, the container app scales in to zero.

You learn how to:

Create a Container Apps environment to deploy your container apps
Create an Azure Storage Queue to send messages to the container app
Deploy your background processing application as a container app
Verify that the queue messages are processed by the container app

Setup

To sign in to Azure from the CLI, run the following command and follow the prompts to complete the authentication process.

Bash
Azure PowerShell

az cloud set -n AzureChinaCloud
az login
# az cloud set -n AzureCloud   //means return to Public Azure.

Connect-AzAccount -Environment AzureChinaCloud

To ensure you're running the latest version of the CLI, run the upgrade command.

Bash
Azure PowerShell

az upgrade

Install-Module -Name Az -Scope CurrentUser -Repository PSGallery -Force

Ignore any warnings about modules currently in use.

Next, install or update the Azure Container Apps extension for the CLI.

If you receive errors about missing parameters when you run az containerapp commands in Azure CLI or cmdlets from the Az.App module in Azure PowerShell, be sure you have the latest version of the Azure Container Apps extension installed.

Bash
Azure PowerShell

az extension add --name containerapp --upgrade

Note

Starting in May 2024, Azure CLI extensions no longer enable preview features by default. To access Container Apps preview features, install the Container Apps extension with --allow-preview true.

az extension add --name containerapp --upgrade --allow-preview true

Install-Module -Name Az.App

Make sure to update the Az.App module to the latest version.

Update-Module -Name Az.App

Now that the current extension or module is installed, register the Microsoft.App and Microsoft.OperationalInsights namespaces.

Note

Azure Container Apps resources have migrated from the Microsoft.Web namespace to the Microsoft.App namespace. Refer to Namespace migration from Azure.Web to Microsoft.App in March 2022 for more details.

Bash
Azure PowerShell

az provider register --namespace Microsoft.App

az provider register --namespace Microsoft.OperationalInsights

Register-AzResourceProvider -ProviderNamespace Microsoft.App

Register-AzResourceProvider -ProviderNamespace Microsoft.OperationalInsights

Set environment variables

Set the following environment variables. Replace the <PLACEHOLDERS> with your values:

Bash
Azure PowerShell

RESOURCE_GROUP="<RESOURCE_GROUP>"
LOCATION="<LOCATION>"
CONTAINERAPPS_ENVIRONMENT="<CONTAINERAPPS_ENVIRONMENT>"

$ResourceGroupName = '<RESOURCE_GROUP>'
$Location = '<LOCATION>'
$ContainerAppsEnvironment = '<CONTAINERAPPS_ENVIRONMENT>'

Create an Azure resource group

Create a resource group to organize the services related to your container app deployment.

Bash
Azure PowerShell

az group create \
  --name $RESOURCE_GROUP \
  --location "$LOCATION"

New-AzResourceGroup -Location $Location -Name $ResourceGroupName

Create an environment

An environment in Azure Container Apps creates a secure boundary around a group of container apps. Container Apps deployed to the same environment are deployed in the same virtual network and write logs to the same Log Analytics workspace.

To create the environment, run the following command:

Bash
Azure PowerShell

az containerapp env create \
  --name $CONTAINERAPPS_ENVIRONMENT \
  --resource-group $RESOURCE_GROUP \
  --location "$LOCATION"

A Log Analytics workspace is required for the Container Apps environment. The following commands create a Log Analytics workspace and save the workspace ID and primary shared key to environment variables.

$WorkspaceArgs = @{
    Name = 'myworkspace'
    ResourceGroupName = $ResourceGroupName
    Location = $Location
    PublicNetworkAccessForIngestion = 'Enabled'
    PublicNetworkAccessForQuery = 'Enabled'
}
New-AzOperationalInsightsWorkspace @WorkspaceArgs
$WorkspaceId = (Get-AzOperationalInsightsWorkspace -ResourceGroupName $ResourceGroupName -Name $WorkspaceArgs.Name).CustomerId
$WorkspaceSharedKey = (Get-AzOperationalInsightsWorkspaceSharedKey -ResourceGroupName $ResourceGroupName -Name $WorkspaceArgs.Name).PrimarySharedKey

To create the environment, run the following command:

$EnvArgs = @{
    EnvName = $ContainerAppsEnvironment
    ResourceGroupName = $ResourceGroupName
    Location = $Location
    AppLogConfigurationDestination = 'log-analytics'
    LogAnalyticConfigurationCustomerId = $WorkspaceId
    LogAnalyticConfigurationSharedKey = $WorkspaceSharedKey
}

New-AzContainerAppManagedEnv @EnvArgs

Set up a storage queue

Begin by defining a name for the storage account. Storage account names must be unique within Azure and be from 3 to 24 characters in length containing numbers and lowercase letters only.

Bash
Azure PowerShell

STORAGE_ACCOUNT_NAME="<STORAGE_ACCOUNT_NAME>"

$StorageAcctName = "<StorageAccountName>"

Create an Azure Storage account.

Bash
Azure PowerShell

az storage account create \
  --name $STORAGE_ACCOUNT_NAME \
  --resource-group $RESOURCE_GROUP \
  --location "$LOCATION" \
  --sku Standard_RAGRS \
  --kind StorageV2

$StorageAcctArgs = @{
    Name = $StorageAcctName
    ResourceGroupName = $ResourceGroupName
    Location = $location
    SkuName = 'Standard_RAGRS'
    Kind = 'StorageV2'
}
$StorageAcct = New-AzStorageAccount @StorageAcctArgs

Next, get the connection string for the queue.

Bash
Azure PowerShell

QUEUE_CONNECTION_STRING=`az storage account show-connection-string -g $RESOURCE_GROUP --name $STORAGE_ACCOUNT_NAME --query connectionString --out json | tr -d '"'`

 $QueueConnectionString = (Get-AzStorageAccount -ResourceGroupName $ResourceGroupName -Name $StorageAcctName).Context.ConnectionString

Now you can create the message queue.

Bash
Azure PowerShell

az storage queue create \
  --name "myqueue" \
  --account-name $STORAGE_ACCOUNT_NAME \
  --connection-string $QUEUE_CONNECTION_STRING

$Queue = New-AzStorageQueue -Name 'myqueue' -Context $StorageAcct.Context

Finally, you can send a message to the queue.

Bash
Azure PowerShell

az storage message put \
  --content "Hello Queue Reader App" \
  --queue-name "myqueue" \
  --connection-string $QUEUE_CONNECTION_STRING

$QueueMessage = [Microsoft.Azure.Storage.Queue.CloudQueueMessage]::new("Hello Queue Reader App")
$Queue.CloudQueue.AddMessageAsync($QueueMessage).GetAwaiter().GetResult()

A result of Microsoft.Azure.Storage.Core.NullType is returned when the message is added to the queue.

Deploy the background application

Create a file named queue.json and paste the following configuration code into the file.

{
    "$schema": "https://schema.management.azure.com/schemas/2019-08-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "location": {
            "defaultValue": "canadacentral",
            "type": "String"
        },
        "environment_name": {
            "type": "String"
        },
        "queueconnection": {
            "type": "secureString"
        }
    },
    "variables": {},
    "resources": [
    {
        "name": "queuereader",
        "type": "Microsoft.App/containerApps",
        "apiVersion": "2022-03-01",
        "kind": "containerapp",
        "location": "[parameters('location')]",
        "properties": {
            "managedEnvironmentId": "[resourceId('Microsoft.App/managedEnvironments', parameters('environment_name'))]",
            "configuration": {
                "activeRevisionsMode": "single",
                "secrets": [
                {
                    "name": "queueconnection",
                    "value": "[parameters('queueconnection')]"
                }]
            },
            "template": {
                "containers": [
                    {
                        "image": "mcr.microsoft.com/azuredocs/containerapps-queuereader",
                        "name": "queuereader",
                        "env": [
                            {
                                "name": "QueueName",
                                "value": "myqueue"
                            },
                            {
                                "name": "QueueConnectionString",
                                "secretRef": "queueconnection"
                            }
                        ]
                    }
                ],
                "scale": {
                    "minReplicas": 1,
                    "maxReplicas": 10,
                    "rules": [
                        {
                            "name": "myqueuerule",
                            "azureQueue": {
                                "queueName": "myqueue",
                                "queueLength": 100,
                                "auth": [
                                    {
                                        "secretRef": "queueconnection",
                                        "triggerParameter": "connection"
                                    }
                                ]
                            }
                        }
                    ]
                }
            }
        }
    }]
}

Now you can create and deploy your container app.

Bash
Azure PowerShell

az deployment group create --resource-group "$RESOURCE_GROUP" \
  --template-file ./queue.json \
  --parameters \
    environment_name="$CONTAINERAPPS_ENVIRONMENT" \
    queueconnection="$QUEUE_CONNECTION_STRING" \
    location="$LOCATION"

$Params = @{
    environment_name = $ContainerAppsEnvironment
    location = $Location
    queueconnection = $QueueConnectionString
}

$DeploymentArgs = @{
     ResourceGroupName = $ResourceGroupName
     TemplateParameterObject = $Params
     TemplateFile = './queue.json'
     SkipTemplateParameterPrompt = $true
}
New-AzResourceGroupDeployment  @DeploymentArgs

This command deploys the demo application from the public container image called mcr.microsoft.com/azuredocs/containerapps-queuereader and sets secrets and environments variables used by the application.

The application scales out to 10 replicas based on the queue length as defined in the scale section of the ARM template.

Verify the result

The container app runs as a background process. As messages arrive from the Azure Storage Queue, the application creates log entries in Log analytics. You must wait a few minutes for the analytics to arrive for the first time before you're able to query the logged data.

Run the following command to see logged messages. This command requires the Log analytics extension, so accept the prompt to install extension when requested.

Bash
Azure PowerShell

LOG_ANALYTICS_WORKSPACE_CLIENT_ID=`az containerapp env show --name $CONTAINERAPPS_ENVIRONMENT --resource-group $RESOURCE_GROUP --query properties.appLogsConfiguration.logAnalyticsConfiguration.customerId --out tsv`

az monitor log-analytics query \
  --workspace $LOG_ANALYTICS_WORKSPACE_CLIENT_ID \
  --analytics-query "ContainerAppConsoleLogs_CL | where ContainerAppName_s == 'queuereader' and Log_s contains 'Message ID' | project Time=TimeGenerated, AppName=ContainerAppName_s, Revision=RevisionName_s, Container=ContainerName_s, Message=Log_s | take 5" \
  --out table

$queryResults = Invoke-AzOperationalInsightsQuery -WorkspaceId $WorkspaceId  -Query "ContainerAppConsoleLogs_CL | where ContainerAppName_s == 'queuereader' and Log_s contains 'Message ID' | project Time=TimeGenerated, AppName=ContainerAppName_s, Revision=RevisionName_s, Container=ContainerName_s, Message=Log_s | take 5"
$queryResults.Results

Tip

Having issues? Let us know on GitHub by opening an issue in the Azure Container Apps repo.

Clean up resources

Once you're done, run the following command to delete the resource group that contains your Container Apps resources.

Caution

The following command deletes the specified resource group and all resources contained within it. If resources outside the scope of this tutorial exist in the specified resource group, they will also be deleted.

Bash
Azure PowerShell

az group delete \
  --resource-group $RESOURCE_GROUP

Remove-AzResourceGroup -Name $ResourceGroupName -Force