Compile Model Preset without External config.json (mlc-ai#1151)

This PR adds support for compiling a preset of models without
having to provide a `config.json` on disk using the commands below:

```diff
python -m mlc_chat.cli.compile \
       --quantization q4f16_1 -o /tmp/1.so \
-       --config /models/Llama-2-7b-chat-hf
+       --config llama2_7b
```

This allows easier testing and binary distribution without having to
depend on external model directory.

python/mlc_chat/cli/compile.py

@@ -27,7 +27,7 @@ def main():
 
     def _parse_config(path: Union[str, Path]) -> Path:
         try:
-            return detect_config(Path(path))
+            return detect_config(path)
         except ValueError as err:
             raise argparse.ArgumentTypeError(f"No valid config.json in: {path}. Error: {err}")
 

python/mlc_chat/compiler/__init__.py

@@ -3,11 +3,8 @@
 but users could optionally import it if they want to use the compiler.
 """
 from . import compiler_pass
-from .compile import (  # pylint: disable=redefined-builtin
-    CompileArgs,
-    OptimizationFlags,
-    compile,
-)
-from .model import MODELS, Model
+from .compile import CompileArgs, compile  # pylint: disable=redefined-builtin
+from .flags_optimization import OptimizationFlags
+from .model import MODEL_PRESETS, MODELS, Model
 from .parameter import ExternMapping, HuggingFaceLoader, QuantizeMapping
 from .quantization import QUANT

python/mlc_chat/compiler/model/__init__.py

@@ -1,2 +1,2 @@
 """Model definition for the compiler."""
-from .model import MODELS, Model
+from .model import MODEL_PRESETS, MODELS, Model

python/mlc_chat/compiler/model/model.py

@@ -61,3 +61,5 @@ class Model:
         quantize={},
     )
 }
+
+MODEL_PRESETS: Dict[str, Dict[str, Any]] = llama_config.CONFIG

python/mlc_chat/support/auto_config.py

@@ -1,8 +1,9 @@
 """Help function for detecting the model configuration file `config.json`"""
 import json
 import logging
+import tempfile
 from pathlib import Path
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Union
 
 from .style import green
 
@@ -14,25 +15,42 @@
 FOUND = green("Found")
 
 
-def detect_config(config_path: Path) -> Path:
-    """Detect and return the path that points to config.json. If config_path is a directory,
+def detect_config(config: Union[str, Path]) -> Path:
+    """Detect and return the path that points to config.json. If `config` is a directory,
     it looks for config.json below it.
 
     Parameters
     ---------
-    config_path : pathlib.Path
-        The path to config.json or the directory containing config.json.
+    config : Union[str, pathlib.Path]
+        The preset name of the model, or the path to `config.json`, or the directory containing
+        `config.json`.
 
     Returns
     -------
     config_json_path : pathlib.Path
         The path points to config.json.
     """
+    from mlc_chat.compiler import (  # pylint: disable=import-outside-toplevel
+        MODEL_PRESETS,
+    )
+
+    if isinstance(config, str) and config in MODEL_PRESETS:
+        content = MODEL_PRESETS[config]
+        temp_file = tempfile.NamedTemporaryFile(  # pylint: disable=consider-using-with
+            suffix=".json",
+            delete=False,
+        )
+        logger.info("%s preset model configuration: %s", FOUND, temp_file.name)
+        config_path = Path(temp_file.name)
+        with config_path.open("w", encoding="utf-8") as config_file:
+            json.dump(content, config_file, indent=2)
+    else:
+        config_path = Path(config)
     if not config_path.exists():
         raise ValueError(f"{config_path} does not exist.")
 
     if config_path.is_dir():
-        # search config.json under config_path
+        # search config.json under config path
         config_json_path = config_path / "config.json"
         if not config_json_path.exists():
             raise ValueError(f"Fail to find config.json under {config_path}.")