add validation for configuration input

llama_toolchain/inference/meta_reference/config.py

@@ -6,9 +6,12 @@
 
 from typing import Optional
 
-from llama_models.schema_utils import json_schema_type
+from llama_models.datatypes import ModelFamily
 
-from pydantic import BaseModel
+from llama_models.schema_utils import json_schema_type
+from llama_models.sku_list import all_registered_models
+
+from pydantic import BaseModel, validator
 
 from llama_toolchain.inference.api import QuantizationConfig
 
@@ -20,3 +23,18 @@ class MetaReferenceImplConfig(BaseModel):
     torch_seed: Optional[int] = None
     max_seq_len: int
     max_batch_size: int = 1
+
+    @validator("model")
+    @classmethod
+    def validate_model(cls, model: str) -> str:
+        permitted_models = [
+            m.descriptor()
+            for m in all_registered_models()
+            if m.model_family == ModelFamily.llama3_1
+        ]
+        if model not in permitted_models:
+            model_list = "\n\t".join(permitted_models)
+            raise ValueError(
+                f"Unknown model: `{model}`. Choose from [\n\t{model_list}\n]"
+            )
+        return model