Port the command-line tools to use model_manager2 (#5546)

* Port the command-line tools to use model_manager2

1.Reimplement the following:

  - invokeai-model-install
  - invokeai-merge
  - invokeai-ti

  To avoid breaking the original modeal manager, the udpated tools
  have been renamed invokeai-model-install2 and invokeai-merge2. The
  textual inversion training script should continue to work with
  existing installations. The "starter" models now live in
  `invokeai/configs/INITIAL_MODELS2.yaml`.

  When the full model manager 2 is in place and working, I'll rename
  these files and commands.

2. Add the `merge` route to the web API. This will merge two or three models,
   resulting a new one.

   - Note that because the model installer selectively installs the `fp16` variant
     of models (rather than both 16- and 32-bit versions as previous),
     the diffusers merge script will choke on any huggingface diffuserse models
     that were downloaded with the new installer. Previously-downloaded models
     should continue to merge correctly. I have a PR
     upstream https://github.com/huggingface/diffusers/pull/6670 to fix
     this.

3. (more important!)
  During implementation of the CLI tools, found and fixed a number of small
  runtime bugs in the model_manager2 implementation:

  - During model database migration, if a registered models file was
    not found on disk, the migration would be aborted. Now the
    offending model is skipped with a log warning.

  - Caught and fixed a condition in which the installer would download the
    entire diffusers repo when the user provided a single `.safetensors`
    file URL.

  - Caught and fixed a condition in which the installer would raise an
    exception and stop the app when a request for an unknown model's metadata
    was passed to Civitai. Now an error is logged and the installer continues.

  - Replaced the LoWRA starter LoRA with FlatColor. The former has been removed
    from Civitai.

* fix ruff issue

---------

Co-authored-by: Lincoln Stein <lstein@gmail.com>

invokeai/app/api/routers/model_records.py

@@ -1,7 +1,7 @@
 # Copyright (c) 2023 Lincoln D. Stein
 """FastAPI route for model configuration records."""
 
-
+import pathlib
 from hashlib import sha1
 from random import randbytes
 from typing import Any, Dict, List, Optional, Set
@@ -27,6 +27,7 @@ from invokeai.backend.model_manager.config import (
     ModelFormat,
     ModelType,
 )
+from invokeai.backend.model_manager.merge import MergeInterpolationMethod, ModelMerger
 from invokeai.backend.model_manager.metadata import AnyModelRepoMetadata
 
 from ..dependencies import ApiDependencies
@@ -415,3 +416,57 @@ async def sync_models_to_config() -> Response:
     """
     ApiDependencies.invoker.services.model_install.sync_to_config()
     return Response(status_code=204)
+
+
+@model_records_router.put(
+    "/merge",
+    operation_id="merge",
+)
+async def merge(
+    keys: List[str] = Body(description="Keys for two to three models to merge", min_length=2, max_length=3),
+    merged_model_name: Optional[str] = Body(description="Name of destination model", default=None),
+    alpha: float = Body(description="Alpha weighting strength to apply to 2d and 3d models", default=0.5),
+    force: bool = Body(
+        description="Force merging of models created with different versions of diffusers",
+        default=False,
+    ),
+    interp: Optional[MergeInterpolationMethod] = Body(description="Interpolation method", default=None),
+    merge_dest_directory: Optional[str] = Body(
+        description="Save the merged model to the designated directory (with 'merged_model_name' appended)",
+        default=None,
+    ),
+) -> AnyModelConfig:
+    """
+    Merge diffusers models.
+
+        keys: List of 2-3 model keys to merge together. All models must use the same base type.
+        merged_model_name: Name for the merged model [Concat model names]
+        alpha: Alpha value (0.0-1.0). Higher values give more weight to the second model [0.5]
+        force: If true, force the merge even if the models were generated by different versions of the diffusers library [False]
+        interp: Interpolation method. One of "weighted_sum", "sigmoid", "inv_sigmoid" or "add_difference" [weighted_sum]
+        merge_dest_directory: Specify a directory to store the merged model in [models directory]
+    """
+    print(f"here i am, keys={keys}")
+    logger = ApiDependencies.invoker.services.logger
+    try:
+        logger.info(f"Merging models: {keys} into {merge_dest_directory or '<MODELS>'}/{merged_model_name}")
+        dest = pathlib.Path(merge_dest_directory) if merge_dest_directory else None
+        installer = ApiDependencies.invoker.services.model_install
+        merger = ModelMerger(installer)
+        model_names = [installer.record_store.get_model(x).name for x in keys]
+        response = merger.merge_diffusion_models_and_save(
+            model_keys=keys,
+            merged_model_name=merged_model_name or "+".join(model_names),
+            alpha=alpha,
+            interp=interp,
+            force=force,
+            merge_dest_directory=dest,
+        )
+    except UnknownModelException:
+        raise HTTPException(
+            status_code=404,
+            detail=f"One or more of the models '{keys}' not found",
+        )
+    except ValueError as e:
+        raise HTTPException(status_code=400, detail=str(e))
+    return response