[Llama2] Prefetch llama2 tokenizer configs (#1824)

-- This commit prefetches llama2 tokenizer configs from shark_tank.

Signed-off-by: Abhishek Varma <abhishek@nod-labs.com>

.gitignore

@@ -196,3 +196,6 @@ db_dir_UserData
 
 # Embeded browser cache and other
 apps/stable_diffusion/web/EBWebView/
+
+# Llama2 tokenizer configs
+llama2_tokenizer_configs/

apps/language_models/scripts/vicuna.py

@@ -1238,10 +1238,6 @@ def __init__(
             max_num_tokens,
             extra_args_cmd=extra_args_cmd,
         )
-        if "llama2" in self.model_name and hf_auth_token == None:
-            raise ValueError(
-                "HF auth token required. Pass it using --hf_auth_token flag."
-            )
         self.hf_auth_token = hf_auth_token
         if self.model_name == "llama2_7b":
             self.hf_model_path = "meta-llama/Llama-2-7b-chat-hf"
@@ -1277,12 +1273,21 @@ def get_model_path(self, suffix="mlir"):
         )
 
     def get_tokenizer(self):
-        kwargs = {"use_auth_token": self.hf_auth_token}
-        tokenizer = AutoTokenizer.from_pretrained(
-            self.hf_model_path,
-            use_fast=False,
-            **kwargs,
-        )
+        local_tokenizer_path = Path(Path.cwd(), "llama2_tokenizer_configs")
+        local_tokenizer_path.mkdir(parents=True, exist_ok=True)
+        tokenizer_files_to_download = [
+            "config.json",
+            "special_tokens_map.json",
+            "tokenizer.model",
+            "tokenizer_config.json",
+        ]
+        for tokenizer_file in tokenizer_files_to_download:
+            download_public_file(
+                f"gs://shark_tank/llama2_tokenizer/{tokenizer_file}",
+                Path(local_tokenizer_path, tokenizer_file),
+                single_file=True,
+            )
+        tokenizer = AutoTokenizer.from_pretrained(str(local_tokenizer_path))
         return tokenizer
 
     def get_src_model(self):