Azure Storage Blob Rust Agent Skill

Azure Blob Storage library for Rust

Client library for Azure Blob Storage — upload, download, and manage blobs and containers.

Use this skill when:

• An app needs to upload or download blobs from Azure Storage in Rust
• You need to create or manage blob containers
• You need to list blobs with pagination
• You need RBAC-based auth for blob operations

> IMPORTANT: Only use the official azure_storage_blob crate published by the azure-sdk crates.io user. Do NOT use the unofficial azure_storage, azure_storage_blobs, or azure_sdk_for_rust community crates. Official crates use underscores in names and none have version 0.21.0.

Installation

cargo add azure_storage_blob azure_identity azure_core tokio futures

> If your code uses azure_core types directly (for example, azure_core::http::Url or azure_core::http::RequestContent), add azure_core to Cargo.toml. If you only use azure_storage_blob re-exports, direct azure_core dependency is optional.

Environment Variables

AZURE_STORAGE_ACCOUNT=<account-name>                         # Preferred when the caller gives an account name
AZURE_STORAGE_ENDPOINT=https://<account>.blob.core.windows.net/ # Optional alternative when the caller gives a full endpoint

When both are available, prefer constructing the endpoint from AZURE_STORAGE_ACCOUNT so the code matches common evaluation prompts.

Authentication

Rust Azure SDK code must not use DefaultAzureCredential. The Rust identity crate does not provide that type.

// Correct for local development
use azure_identity::DeveloperToolsCredential;

let credential = DeveloperToolsCredential::new(None)?;

// Incorrect in Rust: this type does not exist in azure_identity
use azure_identity::DefaultAzureCredential;

use azure_core::http::Url;
use azure_identity::DeveloperToolsCredential;
use azure_storage_blob::BlobServiceClient;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Local dev: DeveloperToolsCredential. Production: use ManagedIdentityCredential.
    let credential = DeveloperToolsCredential::new(None)?;
    let service_url = Url::parse("https://<storage_account_name>.blob.core.windows.net/")?;
    let service_client = BlobServiceClient::new(
        service_url,
        Some(credential),
        None,
    )?;

    // Derive container and blob clients by name.
    let container_client = service_client.blob_container_client("<container_name>");
    let blob_client = container_client.blob_client("<blob_name>");
    Ok(())
}

Client Types

| Client | Purpose |

| --------------------- | ----------------------------------------- |

| BlobServiceClient | Account-level operations, list containers |

| BlobContainerClient | Container operations, list blobs |

| BlobClient | Individual blob operations |

Core Workflow

Upload Blob

use azure_core::http::{RequestContent, Url};
use azure_identity::DeveloperToolsCredential;
use azure_storage_blob::BlobServiceClient;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Local dev: DeveloperToolsCredential. Production: use ManagedIdentityCredential.
    let credential = DeveloperToolsCredential::new(None)?;
    let service_url = Url::parse("https://<storage_account_name>.blob.core.windows.net/")?;
    let service_client = BlobServiceClient::new(service_url, Some(credential), None)?;
    let blob_client = service_client.blob_client("<container_name>", "<blob_name>");

    let data = b"hello world";
    blob_client.upload(RequestContent::from(data.to_vec()), None).await?;
    Ok(())
}

Download Blob / Get Properties

// Get blob properties
let props = blob_client.get_properties(None).await?;

// Download blob content
let response = blob_client.download(None).await?;
let content = String::from_utf8(response.body.collect().await?.into())?;

Delete Blob

blob_client.delete(None).await?;

Container Operations

use azure_core::http::Url;
use azure_identity::DeveloperToolsCredential;
use azure_storage_blob::BlobServiceClient;
use futures::TryStreamExt as _;

let credential = DeveloperToolsCredential::new(None)?;
let service_url = Url::parse("https://<storage_account_name>.blob.core.windows.net/")?;
let service_client = BlobServiceClient::new(service_url, Some(credential), None)?;
let container_client = service_client.blob_container_client("<container_name>");

// Create container
container_client.create(None).await?;

// List blobs (the pager yields BlobItem values directly for this client pattern)
let mut pager = container_client.list_blobs(None)?;
while let Some(blob) = pager.try_next().await? {
    let name = blob.name.as_deref().unwrap_or("<unnamed>");
    let size = blob
        .properties
        .as_ref()
        .and_then(|properties| properties.content_length);

    match size {
        Some(size) => println!("Blob: {name} ({size} bytes)"),
        None => println!("Blob: {name}"),
    }
}

For azure_storage_blob 1.x, do not assume you need a nested page loop like for item in &page.blob_items. In this usage pattern, try_next() already yields the blob item you want to print.

Error Handling

Use StorageError for programmatic access to storage-specific error codes:

use azure_core::error::ErrorKind;
use azure_storage_blob::StorageError;
use azure_storage_blob::models::StorageErrorCode;

let result = blob_client.download(None).await;

match result {
    Ok(response) => {
        let content: Vec<u8> = response.body.collect().await?.into();
        println!("Downloaded {} bytes", content.len());
    }
    Err(error) => {
        if matches!(error.kind(), ErrorKind::HttpResponse { .. }) {
            // Convert to StorageError for programmatic access
            let storage_error: StorageError = error.try_into()?;
            println!("HTTP Status: {}", storage_error.status_code);

            if let Some(error_code) = &storage_error.error_code {
                match error_code {
                    StorageErrorCode::BlobNotFound => {
                        println!("The blob does not exist.");
                    }
                    StorageErrorCode::ContainerNotFound => {
                        println!("The container does not exist.");
                    }
                    StorageErrorCode::AuthorizationFailure => {
                        println!("Authorization failed. Check RBAC roles.");
                    }
                    _ => println!("Storage error: {error_code}"),
                }
            }

            if let Some(request_id) = &storage_error.request_id {
                println!("Request ID (for Azure support): {request_id}");
            }
        } else {
            println!("Non-HTTP error: {:?}", error);
        }
    }
}

> Note: StorageError::try_into requires an owned error object — it will not compile if handed a reference to an error.

RBAC Roles

For Entra ID auth, assign one of these roles to the identity:

| Role | Access |

| ------------------------------- | -------------------------- |

| Storage Blob Data Reader | Read-only |

| Storage Blob Data Contributor | Read/write |

| Storage Blob Data Owner | Full access including RBAC |

Best Practices

• Use cargo add to manage dependencies, never edit Cargo.toml directly. Add and remove Rust SDK dependencies with cargo commands instead of manual manifest edits.
• Add azure_core only when importing azure_core types directly. If your code imports azure_core::http::Url, azure_core::http::RequestContent, or azure_core::error::ErrorKind, include azure_core; otherwise a direct dependency is optional.
• Use DeveloperToolsCredential for local dev, ManagedIdentityCredential for production — Rust does not provide a single DefaultAzureCredential type
• Never hardcode credentials — use environment variables or managed identity
• Use RequestContent::from() to wrap data for blob uploads — ensures proper content handling by the SDK
• Assign RBAC roles — ensure "Storage Blob Data Contributor" for write access
• Reuse clients — clients are thread-safe; create once, share across tasks
• Prefer BlobServiceClient as the entry point and derive container/blob clients from it
• Treat many storage model fields as optional. blob.name is an Option<String> and content length is accessed via blob.properties.as_ref().and_then(|p| p.content_length).

10. Run cargo clippy -- -D warnings before considering the task complete when the prompt or CI expects strict lint compliance; fix style lints such as collapsible if blocks, not just compiler errors.

11. Prefer crate README/examples over generated internal type names when validating public API shapes such as pagination results

12. Future-proof #[non_exhaustive] SDK models — when constructing SDK model/options structs, end the initializer with ..Default::default() (add #[allow(clippy::needless_update)]) and use a _ wildcard arm when matching SDK enums, so new service-added fields/variants don't break your build

Common Rust Blob Pitfalls

• Do not import azure_identity::DefaultAzureCredential; use DeveloperToolsCredential or another real Rust credential type.
• Do not assume generated internal model names describe the public pager item type; follow the documented list_blobs example for this crate.
• Do not print blob.name with {} directly; unwrap or provide a fallback because it is optional.
• Do not stop after cargo build passes when the task also requires cargo clippy -- -D warnings.

Reference Links

| Resource | Link |

| ------------- | ------------------------------------------------------------------------------------ |

| API Reference | https://docs.rs/crate/azure_storage_blob/latest |

| crates.io | https://crates.io/crates/azure_storage_blob |

| Source Code | https://github.com/Azure/azure-sdk-for-rust/tree/main/sdk/storage/azure_storage_blob |