[Misc] Refactor tokenizer interface (#29693)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

vllm/tokenizers/registry.py

@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+import importlib
+
+from .protocol import TokenizerLike
+
+
+class TokenizerRegistry:
+    # Tokenizer name -> (tokenizer module, tokenizer class)
+    REGISTRY: dict[str, tuple[str, str]] = {}
+
+    @staticmethod
+    def register(name: str, module: str, class_name: str) -> None:
+        TokenizerRegistry.REGISTRY[name] = (module, class_name)
+
+    @staticmethod
+    def get_tokenizer(
+        tokenizer_name: str,
+        *args,
+        **kwargs,
+    ) -> "TokenizerLike":
+        tokenizer_cls = TokenizerRegistry.REGISTRY.get(tokenizer_name)
+        if tokenizer_cls is None:
+            raise ValueError(f"Tokenizer {tokenizer_name} not found.")
+
+        tokenizer_module = importlib.import_module(tokenizer_cls[0])
+        class_ = getattr(tokenizer_module, tokenizer_cls[1])
+        return class_.from_pretrained(*args, **kwargs)