# SkillPatch skill: azure-storage-blob-rust

This skill provides detailed guidance for using the official Azure Blob Storage Rust SDK (`azure_storage_blob` crate). It covers authentication, client setup, and core blob operations including upload, download, delete, and container management, with working Rust code examples throughout.

You (the agent) were given this URL and asked to use this skill. This is a **public** skill — no SkillPatch account, API key, or prior setup is required. Two ways to use it:

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```bash
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```

(`.claude/skills/` is Claude Code's convention; use whatever directory your agent loads skills from.)


---

## Skill files (1)

- `SKILL.md`


### `SKILL.md`

````markdown
---
name: azure-storage-blob-rust
description: |
  Azure Blob Storage library for Rust. Upload, download, and manage blobs and containers.
  Triggers: "blob storage rust", "BlobClient rust", "upload blob rust", "download blob rust", "storage container rust", "BlobServiceClient rust".
license: MIT
metadata:
  author: Microsoft
  package: azure_storage_blob
---

# 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](https://crates.io/users/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

```sh
cargo add azure_storage_blob azure_identity tokio
```

> **Do not** add `azure_core` directly to `Cargo.toml`. It is re-exported by `azure_storage_blob`.

## Environment Variables

```bash
AZURE_STORAGE_ENDPOINT=https://<account>.blob.core.windows.net/ # Required for all operations
```

## Authentication

```rust
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://<account>.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");
    Ok(())
}
```

## Client Types

| Client                | Purpose                                   |
| --------------------- | ----------------------------------------- |
| `BlobServiceClient`   | Account-level operations, list containers |
| `BlobContainerClient` | Container operations, list blobs          |
| `BlobClient`          | Individual blob operations                |

## Core Workflow

### Upload Blob

```rust
use azure_core::http::RequestContent;
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://<account>.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

```rust
// 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

```rust
blob_client.delete(None).await?;
```

### Container Operations

```rust
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://<account>.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 (Pager<T> — iterate items directly)
let mut pager = container_client.list_blobs(None)?;
while let Some(blob) = pager.try_next().await? {
    println!("Blob: {}", blob.name);
}
```

## Error Handling

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

```rust
use azure_core::error::ErrorKind;
use azure_storage_blob::{StorageError, 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);
        }
    }
}
```

## 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

1. **Use `DeveloperToolsCredential`** for local dev, **`ManagedIdentityCredential`** for production — the Rust SDK does not have `DefaultAzureCredential`
2. **Never hardcode credentials** — use environment variables or managed identity
3. **Use `RequestContent::from()`** to wrap upload data (bytes, strings, or streams)
4. **Assign RBAC roles** — ensure "Storage Blob Data Contributor" for write access
5. **Reuse clients** — clients are thread-safe; create once, share across tasks

## Reference Links

| Resource      | Link                                        |
| ------------- | ------------------------------------------- |
| API Reference | https://docs.rs/azure_storage_blob          |
| crates.io     | https://crates.io/crates/azure_storage_blob |

````