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storage-blobs-list-go.md

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title List blobs with Go
titleSuffix Azure Storage
description Learn how to list blobs in your storage account using the Azure Storage client library for Go. Code examples show how to list blobs in a flat listing, or how to list blobs hierarchically, as though they were organized into directories or folders.
services storage
author stevenmatthew
ms.service azure-blob-storage
ms.topic how-to
ms.date 08/05/2024
ms.author shaas
ms.devlang golang
ms.custom devx-track-go, devguide-go

List blobs with Go

[!INCLUDE storage-dev-guide-selector-list-blob]

This article shows how to list blobs using the Azure Storage client module for Go.

[!INCLUDE storage-dev-guide-prereqs-go]

Set up your environment

[!INCLUDE storage-dev-guide-project-setup-go]

Authorization

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

About blob listing options

When you list blobs from your code, you can specify many 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 specify a prefix to return blobs whose names begin with that character or string. And you can list blobs in a flat listing structure, or hierarchically. A hierarchical listing returns blobs as though they were organized into folders.

To list the blobs in a container using a flat listing, call the following method:

To list the blobs in a container using a hierarchical listing, call the following method from a container client object:

Manage how many results are returned

By default, a listing operation returns up to 5000 results at a time. To return a smaller set of results, provide a nonzero value for the MaxResults field in ListBlobsFlatOptions or ListBlobsHierarchyOptions.

Filter results with a prefix

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

Include blob metadata or other information

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

See ListBlobsInclude for additional options to include snapshots, versions, blob index tags, and other information with the results.

Flat listing versus hierarchical listing

Blobs in Azure Storage are organized in a flat paradigm, rather than a hierarchical paradigm (like a classic file system). However, you can organize blobs into virtual directories in order to mimic a folder structure. A virtual directory forms part of the name of the blob and is indicated by the delimiter character.

To organize blobs into virtual directories, use a delimiter character in the blob name. The default delimiter character is a forward slash (/), but you can specify any character as the delimiter.

If you name your blobs using a delimiter, then you can choose to list blobs hierarchically. For a hierarchical listing operation, Azure Storage returns any virtual directories and blobs beneath the parent object. You can call the listing operation recursively to traverse the hierarchy, similar to how you would traverse a classic file system programmatically.

Note

Blob snapshots cannot be listed in a hierarchical listing operation.

Use a flat listing

By default, a listing operation returns blobs in a flat listing. In a flat listing, blobs aren't organized by virtual directory.

The following example lists the blobs in the specified container using a flat listing. This example includes blob snapshots and blob versions, if they exist:

:::code language="go" source="~/blob-devguide-go/cmd/list-blobs/list_blobs.go" id="snippet_list_blobs_flat":::

Sample output is similar to:

List blobs flat:
file4.txt
folderA/file1.txt
folderA/file2.txt
folderA/folderB/file3.txt

The following example lists blobs in a container that begin with a specific prefix:

:::code language="go" source="~/blob-devguide-go/cmd/list-blobs/list_blobs.go" id="snippet_list_blobs_flat_options":::

When passing a prefix string of "sample", output is similar to:

List blobs with prefix:
sample-blob1.txt
sample-blob2.txt
sample-blob3.txt

Note

The sample output shown assumes that you have a storage account with a flat namespace. If you've enabled the hierarchical namespace feature for your storage account, directories are not virtual. Instead, they are concrete, independent objects. As a result, directories appear in the list as zero-length blobs.

For an alternative listing option when working with a hierarchical namespace, see NewListPathsPager.

Use a hierarchical listing

When you call a listing operation hierarchically, Azure Storage returns the virtual directories and blobs at the first level of the hierarchy.

To list blobs hierarchically, use the following method:

The following example lists the blobs in the specified container using a hierarchical listing. In this example, the prefix parameter is initially set to an empty string to list all blobs in the container. The example then calls the listing operation recursively to traverse the virtual directory hierarchy and list blobs.

:::code language="go" source="~/blob-devguide-go/cmd/list-blobs/list_blobs.go" id="snippet_list_blobs_hierarchical":::

Sample output is similar to:

Virtual directory prefix: folderA/
Blob: folderA/file1.txt
Blob: folderA/file2.txt
Blob: folderA/file3.txt
Virtual directory prefix: folderA/folderB/
Blob: folderA/folderB/file1.txt
Blob: folderA/folderB/file2.txt
Blob: folderA/folderB/file3.txt

[!INCLUDE storage-dev-guide-code-samples-note-go]

Resources

To learn more about how to list blobs 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 blobs use the following REST API operation:

[!INCLUDE storage-dev-guide-resources-go]

See also

[!INCLUDE storage-dev-guide-next-steps-go]