Sync from v0.13

vllm/lora/resolver.py

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+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from abc import ABC, abstractmethod
+from collections.abc import Set
+from dataclasses import dataclass, field
+
+from vllm.logger import init_logger
+from vllm.lora.request import LoRARequest
+
+logger = init_logger(__name__)
+
+
+class LoRAResolver(ABC):
+    """Base class for LoRA adapter resolvers.
+
+    This class defines the interface for resolving and fetching LoRA adapters.
+    Implementations of this class should handle the logic for locating and
+    downloading LoRA adapters from various sources (e.g. S3, cloud storage,
+    etc.).
+    """
+
+    @abstractmethod
+    async def resolve_lora(
+        self, base_model_name: str, lora_name: str
+    ) -> LoRARequest | None:
+        """Abstract method to resolve and fetch a LoRA model adapter.
+
+        Implements logic to locate and download LoRA adapter based on the name.
+        Implementations might fetch from a blob storage or other sources.
+
+        Args:
+            base_model_name: The name/identifier of the base model to resolve.
+            lora_name: The name/identifier of the LoRA model to resolve.
+
+        Returns:
+            Optional[LoRARequest]: The resolved LoRA model information, or None
+            if the LoRA model cannot be found.
+        """
+        pass
+
+
+@dataclass
+class _LoRAResolverRegistry:
+    resolvers: dict[str, LoRAResolver] = field(default_factory=dict)
+
+    def get_supported_resolvers(self) -> Set[str]:
+        """Get all registered resolver names."""
+        return self.resolvers.keys()
+
+    def register_resolver(
+        self,
+        resolver_name: str,
+        resolver: LoRAResolver,
+    ) -> None:
+        """Register a LoRA resolver.
+        Args:
+            resolver_name: Name to register the resolver under.
+            resolver: The LoRA resolver instance to register.
+        """
+        if resolver_name in self.resolvers:
+            logger.warning(
+                "LoRA resolver %s is already registered, and will be "
+                "overwritten by the new resolver instance %s.",
+                resolver_name,
+                resolver,
+            )
+
+        self.resolvers[resolver_name] = resolver
+
+    def get_resolver(self, resolver_name: str) -> LoRAResolver:
+        """Get a registered resolver instance by name.
+        Args:
+            resolver_name: Name of the resolver to get.
+        Returns:
+            The resolver instance.
+        Raises:
+            KeyError: If the resolver is not found in the registry.
+        """
+        if resolver_name not in self.resolvers:
+            raise KeyError(
+                f"LoRA resolver '{resolver_name}' not found. "
+                f"Available resolvers: {list(self.resolvers.keys())}"
+            )
+        return self.resolvers[resolver_name]
+
+
+LoRAResolverRegistry = _LoRAResolverRegistry()