convert : allow using lazy remote tensors

It's a bit slow for now since everything is blocking and single-threaded.

convert_hf_to_gguf.py

@@ -73,7 +73,7 @@ class Model:
                  use_temp_file: bool = False, eager: bool = False,
                  metadata_override: Path | None = None, model_name: str | None = None,
                  split_max_tensors: int = 0, split_max_size: int = 0, dry_run: bool = False,
-                 small_first_shard: bool = False, hparams: dict[str, Any] | None = None):
+                 small_first_shard: bool = False, hparams: dict[str, Any] | None = None, remote_hf_model_id: str | None = None):
         if type(self) is Model:
             raise TypeError(f"{type(self).__name__!r} should not be directly instantiated")
 
@@ -83,7 +83,19 @@ class Model:
         self.is_big_endian = is_big_endian
         self.endianess = gguf.GGUFEndian.BIG if is_big_endian else gguf.GGUFEndian.LITTLE
         self.use_temp_file = use_temp_file
-        self.lazy = not eager
+        self.lazy = not eager or (remote_hf_model_id is not None)
+        if remote_hf_model_id is not None:
+            self.is_safetensors = True
+
+            def get_remote_tensors() -> Iterator[tuple[str, Tensor]]:
+                logger.info(f"Using remote model with HuggingFace id: {remote_hf_model_id}")
+                remote_tensors = gguf.utility.SafetensorRemote.get_list_tensors_hf_model(remote_hf_model_id)
+                self.tensor_names = set(name for name in remote_tensors.keys())
+                for name, remote_tensor in gguf.utility.SafetensorRemote.get_list_tensors_hf_model(remote_hf_model_id).items():
+                    yield (name, LazyTorchTensor.from_remote_tensor(remote_tensor))
+
+            self.get_tensors = get_remote_tensors
+        else:
             self.part_names = Model.get_model_part_names(self.dir_model, "model", ".safetensors")
             self.is_safetensors = len(self.part_names) > 0
             if not self.is_safetensors:
@@ -5393,6 +5405,14 @@ class LazyTorchTensor(gguf.LazyBase):
         lazy = cls(meta=cls.meta_with_dtype_and_shape(dtype, shape), args=(st_slice,), func=lambda s: s[:])
         return cast(torch.Tensor, lazy)
 
+    @classmethod
+    def from_remote_tensor(cls, remote_tensor: gguf.utility.RemoteTensor):
+        dtype = cls._dtype_str_map[remote_tensor.dtype]
+        shape = remote_tensor.shape
+        meta = cls.meta_with_dtype_and_shape(dtype, shape)
+        lazy = cls(meta=meta, args=(remote_tensor,), func=lambda r: torch.frombuffer(r.data(), dtype=dtype).reshape(shape))
+        return cast(torch.Tensor, lazy)
+
     @classmethod
     def __torch_function__(cls, func, types, args=(), kwargs=None):
         del types  # unused
@@ -5516,8 +5536,9 @@ def main() -> None:
 
     if args.remote:
         from huggingface_hub import snapshot_download
+        args.remote = str(dir_model)
         local_dir = snapshot_download(
-            repo_id=str(dir_model),
+            repo_id=args.remote,
             allow_patterns=["LICENSE", "*.json", "*.md", "*.txt", "tokenizer.model"])
         dir_model = Path(local_dir)
         logger.info(f"Downloaded config and tokenizer to {local_dir}")
@@ -5569,7 +5590,7 @@ def main() -> None:
                                      metadata_override=args.metadata, model_name=args.model_name,
                                      split_max_tensors=args.split_max_tensors,
                                      split_max_size=split_str_to_n_bytes(args.split_max_size), dry_run=args.dry_run,
-                                     small_first_shard=args.no_tensor_first_split)
+                                     small_first_shard=args.no_tensor_first_split, remote_hf_model_id=args.remote or None)
 
         if args.vocab_only:
             logger.info("Exporting model vocab...")

gguf-py/gguf/utility.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from dataclasses import dataclass
 from typing import Literal
 
 import json
@@ -71,6 +72,20 @@ def naming_convention(model_name: str | None, base_name: str | None, finetune_st
     return f"{name}{parameters}{finetune}{version}{encoding}{kind}"
 
 
+@dataclass
+class RemoteTensor:
+    dtype: str
+    shape: tuple[int, ...]
+    offset_start: int
+    size: int
+    url: str
+
+    def data(self) -> bytes:
+        # TODO: handle request errors (maybe with limited retries?)
+        data = SafetensorRemote.get_data_by_range(url=self.url, start=self.offset_start, size=self.size)
+        return data
+
+
 class SafetensorRemote:
     """
     Uility class to handle remote safetensor files.
@@ -94,7 +109,7 @@ class SafetensorRemote:
     ALIGNMENT = 8 # bytes
 
     @classmethod
-    def get_list_tensors_hf_model(cls, model_id: str) -> dict[str, tuple[str, list[int], int, int, str]]:
+    def get_list_tensors_hf_model(cls, model_id: str) -> dict[str, RemoteTensor]:
         """
         Get list of tensors from a Hugging Face model repository.
 
@@ -105,10 +120,7 @@ class SafetensorRemote:
         is_single_file = cls.check_file_exist(f"{cls.BASE_DOMAIN}/{model_id}/resolve/main/model.safetensors")
         if is_single_file:
             url = f"{cls.BASE_DOMAIN}/{model_id}/resolve/main/model.safetensors"
-            tensors: dict[str, tuple[str, list[int], int, int, str]] = {}
+            return cls.get_list_tensors(url)
-            for key, val in cls.get_list_tensors(url).items():
-                tensors[key] = (*val, url) # populate the url
-            return tensors
 
         # case 2: model has multiple files
         index_url = f"{cls.BASE_DOMAIN}/{model_id}/resolve/main/model.safetensors.index.json"
@@ -124,17 +136,17 @@ class SafetensorRemote:
             all_files = list(set(weight_map.values()))
             all_files.sort() # make sure we load shard files in order
             # get the list of tensors
-            tensors = {}
+            tensors: dict[str, RemoteTensor] = {}
             for file in all_files:
                 url = f"{cls.BASE_DOMAIN}/{model_id}/resolve/main/{file}"
                 for key, val in cls.get_list_tensors(url).items():
-                    tensors[key] = (*val, url) # populate the url
+                    tensors[key] = val
             return tensors
 
         raise ValueError(f"Model {model_id} does not have any safetensor files")
 
     @classmethod
-    def get_list_tensors(cls, url: str) -> dict[str, tuple[str, list[int], int, int]]:
+    def get_list_tensors(cls, url: str) -> dict[str, RemoteTensor]:
         """
         Get list of tensors from a remote safetensor file.
 
@@ -142,7 +154,7 @@ class SafetensorRemote:
         Each tensor is represented as a tuple of (dtype, shape, offset_start, size)
         """
         metadata, data_start_offset = cls.get_metadata(url)
-        res: dict[str, tuple[str, list[int], int, int]] = {}
+        res: dict[str, RemoteTensor] = {}
 
         for name, meta in metadata.items():
             if name == "__metadata__":
@@ -155,7 +167,7 @@ class SafetensorRemote:
                 offset_start_relative, offset_end_relative = meta["data_offsets"]
                 size = offset_end_relative - offset_start_relative
                 offset_start = data_start_offset + offset_start_relative
-                res[name] = (dtype, shape, offset_start, size)
+                res[name] = RemoteTensor(dtype=dtype, shape=tuple(shape), offset_start=offset_start, size=size, url=url)
             except KeyError as e:
                 raise ValueError(f"Missing key in metadata for tensor '{name}': {e}, meta = {meta}")