Overview of the Azure SDK for Go management libraries

Artikkeli
06/17/2024

As explained in the article What is the Azure SDK for Go?, the Azure SDK for Go contains a set of management and client libraries. The management libraries share many features such as Azure Identity support, HTTP pipeline, and error-handling. You can find the full list of the management libraries on the Azure SDK for Go module page.

In this article, you learn the basic steps of how to use the management libraries to interact with Azure resources.

Installing Go packages

In most projects, you install the Go packages for versioning and dependency management.

To install a Go package, use the go get command.

For example, to install the armcompute package, you run the following at the command line:

go get github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute/armcompute

In most Go apps, you install the following packages for authentication:

github.com/Azure/azure-sdk-for-go/sdk/azcore/to
github.com/Azure/azure-sdk-for-go/sdk/azidentity

Importing packages into your Go code

Once downloaded, the package are imported into your app via the import statement:

import (
    "github.com/Azure/azure-sdk-for-go/sdk/azcore/to"
    "github.com/Azure/azure-sdk-for-go/sdk/azidentity"
    "github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute/armcompute"
)

Authenticating to Azure

To run code against an Azure subscription, you need to authenticate to Azure. The azidentity package supports multiple options to authenticate to Azure. These options include client/secret, certificate, and managed identity.

The default authentication option is DefaultAzureCredential, which uses the environment variables set earlier in this article. In your Go code, you create an azidentity object as follows:

cred, err := azidentity.NewDefaultAzureCredential(nil)
if err != nil {
  // handle error
}

Creating a Resource Management client

Once you have a credential from Azure Identity, create a client to connect to the target Azure service.

For example, let's say you want to connect to the Azure Compute service. The Compute package consist of one or more clients. A client groups a set of related APIs, providing access to its functionality within the specified subscription. You create one or more clients to access the APIs you require.

In the following code snippet, the armcompute.NewVirtualMachinesClient type is used to create a client to manage virtual machines:

client, err := armcompute.NewVirtualMachinesClient("<subscription ID>", cred, nil)
if err != nil {
  // handle error
}

The same pattern is used to connect with other Azure services. For example, install the armnetwork package and create a virtual network client to manage virtual network (VNET) resources.

client, err := armnetwork.NewVirtualNetworksClient("<subscription ID>", cred, nil)
if err != nil {
  // handle error
}

Code sample:

package main

import (
	"github.com/Azure/azure-sdk-for-go/sdk/azidentity"
	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/compute/armcompute"
)

func main() {
	cred, err := azidentity.NewDefaultAzureCredential(nil)
	if err != nil {
		// handle error
	}
	client, err := armcompute.NewVirtualMachinesClient("SubID", cred, nil)
	if err != nil {
        // handle error
    }
}

Using the Azure SDK for Go reference documentation

Once instantiated, clients are used to make API calls against your Azure resources. For resource management scenarios, most of the use-cases are CRUD (Create/Read/Update/Delete) operations.

To look up the operations for a specific type, do the following steps:

Browse to the Azure SDK for Go reference documentation.
Search the page for the package. (Pressing <Ctrl+F> automatically expands all nodes on the page for searching.)
Select the package.
Search the package's page for the type.
Read the type's description and information about its usage in your Go code.

You can also manually build the URL by appending the name of the package to github.com/Azure/azure-sdk-for-go/sdk/.

For example, if you're looking for the compute/armcompute reference documentation, the URL is github.com/Azure/azure-sdk-for-go/sdk/compute/armcompute.

The following example shows how to find the reference documentation for Azure resource group operations:

Browse to the main Azure SDK for Go reference documentation on pkg.go.dev.
Select <Ctrl+F> and enter resourcemanager/resources/armresources. As you type the search term, you see a close match with the resources/armresources package.
Select the appropriate package for your application.
Read through "Getting Started" sections or search for a specific operation. For example, searching for the term "resourcegroupsclient.create" (if you want to create a resource group) leads you to the CreateOrUpdate function.
At this point, you can read how to make the API call to create an Azure resource group.

Long-running operations

As some operations can take a long time to complete, the management libraries contain functions to support long-running operations (LRO) via asynchronous calls. These function names start with Begin. Examples of this pattern are BeginCreate and BeginDelete.

As these functions are asynchronous, your code doesn't block until the function finishes its task. Instead, the function returns a poller object immediately. Your code then calls a synchronous poller function that returns when the original asynchronous function completes.

The following code snippet shows an example of this pattern.

ctx := context.Background()
// Call an asynchronous function to create a client. The return value is a poller object.
poller, err := client.BeginCreate(ctx, "resource_identifier", "additional_parameter")

if err != nil {
	// handle error...
}

// Call the poller object's PollUntilDone function that will block until the poller object
// has been updated to indicate the task has completed.
resp, err = poller.PollUntilDone(ctx, nil)
if err != nil {
	// handle error...
}

// Print the fact that the LRO completed.
fmt.Printf("LRO done")

// Work with the response ("resp") object.

Key points:

The PollUntilDone function requires a polling interval that specifies how often it should try to get the status.
The interval is typically short. See the documentation for the specific Azure resource for recommended intervals.
The LRO section of the Go Azure SDK Design Guidelines page has a move advanced example and general guidelines for LRO.

Next steps

Manage Azure resource groups

Jaa