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List blob containers with Go

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When you list the containers in an Azure Storage account from your code, you can specify several options to manage how results are returned from Azure Storage. This article shows how to list containers using the Azure Storage client module for Go.

Prerequisites

Set up your environment

If you don't have an existing project, this section shows how to set up a project to work with the Azure Blob Storage client module for Go. The steps include module installation, adding import paths, and creating an authorized client object. For details, see Get started with Azure Blob Storage and Go.

Install modules

Install the azblob module using the following command:

go get github.com/Azure/azure-sdk-for-go/sdk/storage/azblob

To authenticate with Microsoft Entra ID (recommended), install the azidentity module using the following command:

go get github.com/Azure/azure-sdk-for-go/sdk/azidentity

Add import paths

In your code file, add the following import paths:

import (
    "github.com/Azure/azure-sdk-for-go/sdk/azidentity"
	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob"
)

Some code examples in this article might require additional import paths. For specific details and example usage, see Code samples.

Create a client object

To connect an app to Blob Storage, create a client object using azblob.NewClient. The following example shows how to create a client object using DefaultAzureCredential for authorization:

func getServiceClientTokenCredential(accountURL string) *azblob.Client {
    // Create a new service client with token credential
    credential, err := azidentity.NewDefaultAzureCredential(nil)
    handleError(err)

    client, err := azblob.NewClient(accountURL, credential, nil)
    handleError(err)

    return client
}

Authorization

The authorization mechanism must have the necessary permissions to list blob containers. For authorization with Microsoft Entra ID (recommended), you need Azure RBAC built-in role Storage Blob Data Contributor or higher. To learn more, see the authorization guidance for List Containers (REST API).

About container listing options

When listing containers from your code, you can specify options to manage how results are returned from Azure Storage. You can specify the number of results to return in each set of results, and then retrieve the subsequent sets. You can also filter the results by a prefix, and return container metadata with the results. These options are described in the following sections.

To list containers in a storage account, call the following method:

This method returns a Pager, which allows your app to process one page of results at a time. Containers are ordered lexicographically by name.

You can specify options for listing containers by using the ListContainersOptions struct. This struct includes fields for managing the number of results, filtering by prefix, and including container information usingListContainersInclude.

Manage how many results are returned

By default, a listing operation returns up to 5,000 results at a time. To return a smaller set of results, provide a nonzero value for the MaxResults field in the ListContainersOptions struct.

Filter results with a prefix

To filter the list of containers, specify a string or character for the Prefix field in ListContainersOptions. The prefix string can include one or more characters. Azure Storage then returns only the containers whose names start with that prefix.

Include container metadata

To include container metadata with the results, set the Metadata field to true as part of ListContainersInclude. Azure Storage includes metadata with each container returned, so you don't need to fetch the container metadata separately.

Include deleted containers

To include soft-deleted containers with the results, set the Deleted field to true as part of ListContainersInclude.

Code examples

The following example lists all containers and metadata:

func listContainers(client *azblob.Client) {
    // List the containers in the storage account and include metadata
    pager := client.NewListContainersPager(&azblob.ListContainersOptions{
        Include: azblob.ListContainersInclude{Metadata: true},
    })

    for pager.More() {
        resp, err := pager.NextPage(context.TODO())
        handleError(err)

        for _, container := range resp.ContainerItems {
            fmt.Println(*container.Name)
            for k, v := range container.Metadata {
                fmt.Printf("%v: %v\n", k, *v)
            }
        }
    }
}

The following example lists only containers that begin with the specified prefix:

func listContainersWithPrefix(client *azblob.Client, prefix string) {
    // List the containers in the storage account with a prefix
    pager := client.NewListContainersPager(&azblob.ListContainersOptions{
        Prefix: &prefix,
    })

    for pager.More() {
        resp, err := pager.NextPage(context.TODO())
        handleError(err)

        for _, container := range resp.ContainerItems {
            fmt.Println(*container.Name)
        }
    }
}

You can also specify a limit for the number of results per page. This example passes in a value for MaxResults and paginates the results:

func listContainersWithMaxResults(client *azblob.Client, maxResults int32) {
    // List the containers in the storage account with a maximum number of results
    pager := client.NewListContainersPager(&azblob.ListContainersOptions{
        MaxResults: &maxResults,
    })

    i := 0
    for pager.More() {
        resp, err := pager.NextPage(context.TODO())
        handleError(err)

        // Show page number to demonstrate pagination with max results
        i++
        fmt.Printf("Page %d:\n", i)

        for _, container := range resp.ContainerItems {
            fmt.Println(*container.Name)
        }
    }
}

Note

The code samples in this guide are intended to help you get started with Azure Blob Storage and Go. You should modify error handling and Context values to meet the needs of your application.

Resources

To learn more about listing containers using the Azure Blob Storage client module for Go, see the following resources.

Code samples

REST API operations

The Azure SDK for Go contains libraries that build on top of the Azure REST API, allowing you to interact with REST API operations through familiar Go paradigms. The client library methods for listing containers use the following REST API operation:

Client module resources

See also