[connector] Add Azure Blob Storage connector (az:// and *.blob.core.windows.net URLs) (#23995)

python/sglang/srt/connector/__init__.py

@@ -22,6 +22,17 @@ class ConnectorType(str, enum.Enum):
     INSTANCE = "instance"
 
 
+def _is_azure_blob_url(url: str, connector_type: str) -> bool:
+    """Detect Azure Blob Storage URLs.
+
+    Matches ``az://...`` URLs and ``https://<account>.blob.core.windows.net/...``
+    URLs, which are the two forms accepted by the ``blobfile`` library.
+    """
+    if connector_type == "az":
+        return True
+    return connector_type == "https" and ".blob.core.windows.net" in url
+
+
 def create_remote_connector(url, device=None, **kwargs) -> BaseConnector:
     connector_type = parse_connector_type(url)
     if connector_type == "redis":
@@ -30,6 +41,12 @@ def create_remote_connector(url, device=None, **kwargs) -> BaseConnector:
         return S3Connector(url)
     elif connector_type == "instance":
         return RemoteInstanceConnector(url, device)
+    elif _is_azure_blob_url(url, connector_type):
+        # Imported lazily so the optional ``blobfile`` dependency is only
+        # required when an Azure URL is actually used.
+        from sglang.srt.connector.azure import AzureBlobConnector
+
+        return AzureBlobConnector(url)
     else:
         raise ValueError(f"Invalid connector type: {url}")
 

python/sglang/srt/connector/azure.py

@@ -0,0 +1,127 @@
+# SPDX-License-Identifier: Apache-2.0
+
+import fnmatch
+import os
+from pathlib import Path
+from typing import Generator, Optional, Tuple
+
+import torch
+
+from sglang.srt.connector import BaseFileConnector
+
+
+def _filter_allow(paths: list[str], patterns: list[str]) -> list[str]:
+    return [
+        path
+        for path in paths
+        if any(fnmatch.fnmatch(path, pattern) for pattern in patterns)
+    ]
+
+
+def _filter_ignore(paths: list[str], patterns: list[str]) -> list[str]:
+    return [
+        path
+        for path in paths
+        if not any(fnmatch.fnmatch(path, pattern) for pattern in patterns)
+    ]
+
+
+def _normalize_url(url: str) -> str:
+    """Strip trailing slash so blobfile glob/listdir behave consistently."""
+    return url.rstrip("/")
+
+
+def list_files(
+    bf,
+    path: str,
+    allow_pattern: Optional[list[str]] = None,
+    ignore_pattern: Optional[list[str]] = None,
+) -> Tuple[str, list[str]]:
+    """List files from an Azure Blob Storage path and filter by pattern.
+
+    Args:
+        bf: The ``blobfile`` module.
+        path: An ``az://<account>/<container>/<prefix>`` or
+            ``https://<account>.blob.core.windows.net/<container>/<prefix>`` URL.
+        allow_pattern: A list of fnmatch patterns of which files to keep.
+        ignore_pattern: A list of fnmatch patterns of which files to drop.
+
+    Returns:
+        A tuple ``(base_dir, files)`` where ``base_dir`` is the normalized
+        prefix used as a directory anchor for relative paths, and ``files``
+        is the list of full URLs matched by the patterns.
+    """
+    base_dir = _normalize_url(path)
+    files = [p for p in bf.glob(base_dir + "/**") if not bf.isdir(p)]
+
+    files = _filter_ignore(files, ["*/"])
+    if allow_pattern is not None:
+        files = _filter_allow(files, allow_pattern)
+    if ignore_pattern is not None:
+        files = _filter_ignore(files, ignore_pattern)
+
+    return base_dir, files
+
+
+class AzureBlobConnector(BaseFileConnector):
+    """File connector for Azure Blob Storage.
+
+    Accepts both ``az://<account>/<container>/<path>`` URLs and HTTPS URLs of
+    the form ``https://<account>.blob.core.windows.net/<container>/<path>``.
+    Uses the third-party ``blobfile`` package, which handles authentication via
+    standard Azure credential chains (env vars, az CLI, managed identity).
+    """
+
+    def __init__(self, url: str) -> None:
+        try:
+            import blobfile as bf
+        except ImportError as e:
+            raise ImportError(
+                "AzureBlobConnector requires the 'blobfile' package. "
+                "Install it with `pip install blobfile`."
+            ) from e
+
+        super().__init__(url)
+        self.bf = bf
+
+    def glob(self, allow_pattern: Optional[list[str]] = None) -> list[str]:
+        _, files = list_files(self.bf, self.url, allow_pattern=allow_pattern)
+        return files
+
+    def pull_files(
+        self,
+        allow_pattern: Optional[list[str]] = None,
+        ignore_pattern: Optional[list[str]] = None,
+    ) -> None:
+        """Download files from Azure Blob Storage to ``self.local_dir``."""
+        base_dir, files = list_files(self.bf, self.url, allow_pattern, ignore_pattern)
+        if not files:
+            return
+
+        for file in files:
+            relative = file[len(base_dir) :].lstrip("/")
+            destination_file = os.path.join(self.local_dir, relative)
+            os.makedirs(Path(destination_file).parent, exist_ok=True)
+            self.bf.copy(file, destination_file, overwrite=True)
+
+    def weight_iterator(
+        self, rank: int = 0
+    ) -> Generator[Tuple[str, torch.Tensor], None, None]:
+        from sglang.srt.model_loader.weight_utils import (
+            runai_safetensors_weights_iterator,
+        )
+
+        # Pull *.safetensors locally first since runai_safetensors_weights_iterator
+        # expects local files. blobfile does not provide a streaming safetensors
+        # reader compatible with runai_model_streamer.
+        self.pull_files(allow_pattern=["*.safetensors"])
+        local_files = [
+            os.path.join(root, f)
+            for root, _, fs in os.walk(self.local_dir)
+            for f in fs
+            if f.endswith(".safetensors")
+        ]
+        return runai_safetensors_weights_iterator(local_files)
+
+    def close(self):
+        super().close()