storage-blob-sample

page_type	languages	products	name	description
sample	java	azure-blob-storage	Reading and Writing Files Stored in Azure Storage Blob by Spring Resource Abstraction in Spring Boot Application	This sample demonstrates how to read and write files in Azure Storage Blob and Spring Resource abstraction in Spring Boot application.

Reading and Writing Files Stored in Azure Storage Blob by Spring Resource Abstraction in Spring Boot Application

This code sample demonstrates how to read and write files with the Spring Resource abstraction for Azure Storage using the Spring Cloud Azure storage starter.

What You Will Build

You will build an application that use Spring Resource abstraction to read and write data with Azure Storage Blob.

What You Need

• An Azure subscription
• Terraform
• Azure CLI
• JDK8 or later
• Maven
• You can also import the code straight into your IDE:
  • IntelliJ IDEA

Provision Azure Resources Required to Run This Sample

This sample will create Azure resources using Terraform. If you choose to run it without using Terraform to provision resources, please pay attention to:

Important

If you choose to use a security principal to authenticate and authorize with Microsoft Entra ID for accessing an Azure resource please refer to Authorize access with Microsoft Entra ID to make sure the security principal has been granted the sufficient permission to access the Azure resource.

Authenticate Using the Azure CLI

Terraform must authenticate to Azure to create infrastructure.

In your terminal, use the Azure CLI tool to setup your account permissions locally.

az login

Your browser window will open and you will be prompted to enter your Azure login credentials. After successful authentication, your terminal will display your subscription information. You do not need to save this output as it is saved in your system for Terraform to use.

You have logged in. Now let us find all the subscriptions to which you have access...

[
  {
    "cloudName": "AzureCloud",
    "homeTenantId": "home-Tenant-Id",
    "id": "subscription-id",
    "isDefault": true,
    "managedByTenants": [],
    "name": "Subscription-Name",
    "state": "Enabled",
    "tenantId": "0envbwi39-TenantId",
    "user": {
      "name": "[email protected]",
      "type": "user"
    }
  }
]

If you have more than one subscription, specify the subscription-id you want to use with command below:

az account set --subscription <your-subscription-id>

Provision the Resources

After login Azure CLI with your account, now you can use the terraform script to create Azure Resources.

Run with Bash

# In the root directory of the sample
# Initialize your Terraform configuration
terraform -chdir=./terraform init

# Apply your Terraform Configuration
terraform -chdir=./terraform apply -auto-approve

Run with Powershell

# In the root directory of the sample
# Initialize your Terraform configuration
terraform -chdir=terraform init

# Apply your Terraform Configuration
terraform -chdir=terraform apply -auto-approve

It may take a few minutes to run the script. After successful running, you will see prompt information like below:

azurerm_resource_group.main: Creating...
azurerm_resource_group.main: Creation complete after 3s ...
azurerm_storage_account.application: Creating...
azurerm_storage_account.application: Still creating... [10s elapsed]
azurerm_storage_account.application: Creation complete after 39s ...
azurerm_storage_container.application: Creating...
azurerm_storage_container.application: Creation complete after 1s ...
azurerm_role_assignment.storage_blob_contributor: Creating...
azurerm_role_assignment.storage_blob_contributor: Still creating... [20s elapsed]
azurerm_role_assignment.storage_blob_contributor: Creation complete after 26s...

...
Apply complete! Resources: 6 added, 0 changed, 0 destroyed.

You can go to Azure portal in your web browser to check the resources you created.

Export Output to Your Local Environment

Running the command below to export environment values:

Run with Bash

source ./terraform/setup_env.sh

Run with Powershell

terraform\setup_env.ps1

If you want to run the sample in debug mode, you can save the output value.

AZURE_STORAGE_ACCOUNT=...
STORAGE_CONTAINER_NAME=...

Run Locally

Run the sample with Maven

In your terminal, run mvn clean spring-boot:run.

mvn clean spring-boot:run

Run the sample in IDEs

You can debug your sample by adding the saved output values to the tool's environment variables or the sample's application.yaml file.

• If your tool is IDEA, please refer to Debug your first Java application and add environment variables.

• If your tool is ECLIPSE, please refer to Debugging the Eclipse IDE for Java Developers and Eclipse Environment Variable Setup.

Verify This Sample

1. Write and read a file.
   1.1 Send a POST request to update file contents.

   curl http://localhost:8080/blob/file1.txt -d "new message" -H "Content-Type: text/plain"

   1.2 Verify by sending a GET request.

   curl -XGET http://localhost:8080/blob/file1.txt

2. [Optional] Using AzureStorageBlobProtocolResolver to get Azure Storage Blob resources with file pattern.

   curl -XGET http://localhost:8080/blob

   Verify in app's log that a similar messages was posted:

   10 resources founded with pattern:*.txt

Clean Up Resources

After running the sample, if you don't want to run the sample, remember to destroy the Azure resources you created to avoid unnecessary billing.

The terraform destroy command terminates resources managed by your Terraform project.
To destroy the resources you created.

Run with Bash

terraform -chdir=./terraform destroy -auto-approve

Run with Powershell

terraform -chdir=terraform destroy -auto-approve

Deploy to Azure Spring Apps

Now that you have the Spring Boot application running locally, it's time to move it to production. Azure Spring Apps makes it easy to deploy Spring Boot applications to Azure without any code changes. The service manages the infrastructure of Spring applications so developers can focus on their code. Azure Spring Apps provides lifecycle management using comprehensive monitoring and diagnostics, configuration management, service discovery, CI/CD integration, blue-green deployments, and more. To deploy your application to Azure Spring Apps, see Deploy your first application to Azure Spring Apps.