[ChrisPC-39]

Add Azure Blob Storage Provider Support

Summary

Adds native Azure Blob Storage support to chuk-artifacts, providing seamless integration with Microsoft Azure cloud storage alongside existing S3 and IBM COS providers.

New Provider Implementation

• src/chuk_artifacts/providers/azure_blob.py - Full S3-compatible Azure Blob Storage provider
  • Three authentication methods:
    • Connection string (simple, account key-based)
    • Account name + key (account key-based)
    • Azure AD (Microsoft Entra ID) - identity-based authentication
  • Dual presigned URL generation:
    • Account Key SAS (traditional)
    • User Delegation SAS (Azure AD-based) - works without "Allow Blob anonymous access"
  • Async/await throughout with proper resource cleanup

Dependencies

• pyproject.toml
  • azure-storage-blob>=12.19.0
  • azure-identity>=1.15.0 (for Azure AD support)

Testing

• tests/providers/test_azure_blob_provider.py - 17 comprehensive unit tests

  • Factory initialization with multiple credential types
  • Error handling (missing credentials, blob not found)
  • Account Key SAS presigned URL generation

• tests/providers/test_azure_blob_integration.py - Integration tests

  • Real Azure account testing
  • Azure AD integration test (skipped unless AZURE_USE_AD=true set)
  • Tests upload, download, presigned URLs with Azure AD

Documentation

Updated both:

• README.md
• examples/11_azure_blob_quickstart.py

Configuration

Users can now configure Azure Blob Storage with three authentication methods:

Option 1: Connection String (Simple)

export ARTIFACT_PROVIDER=azure_blob
export AZURE_STORAGE_CONNECTION_STRING="DefaultEndpointsProtocol=https;AccountName=...;AccountKey=...;EndpointSuffix=core.windows.net"
export ARTIFACT_BUCKET=my-container

### Option 2: Account Name + Key (Traditional)
```bash
export ARTIFACT_PROVIDER=azure_blob
export AZURE_STORAGE_ACCOUNT_NAME=myaccount
export AZURE_STORAGE_ACCOUNT_KEY=base64key...
export ARTIFACT_BUCKET=my-container

Option 3: Azure AD Authentication

export ARTIFACT_PROVIDER=azure_blob
export AZURE_STORAGE_ACCOUNT_NAME=myaccount
export AZURE_USE_AD=true

# Option 3a: Service Principal (apps/CI/CD)
export AZURE_CLIENT_ID=your-client-id
export AZURE_CLIENT_SECRET=your-client-secret
export AZURE_TENANT_ID=your-tenant-id

# Option 3b: Managed Identity (Azure VM/AKS/Functions)
# No credentials needed - automatic!

# Option 3c: Azure CLI (local development)
# Just run: az login

[krialm]

1. pyproject.toml adds both azure packages to core dependencies and no [project.optional-dependencies] azure group is defined (the repo only has a dev extra). I think this example can be removed as long as they are not valid.

[krialm]

also at ## Examples tab we can add example referencing to 11_azure_blob_quickstart.py file.

[krialm]

not related to your changes, maybe it is better to use StorageProvider enum type from types.py instead of updating available list

[krialm]

No critical blockers found, only minor improvements suggested

[madhav165]

PR looks good. Follows the patterns established for S3 storage.

Minor observation: azure dependencies would always be installed even if not being configured with the current pyproject.toml.