feat(nodes): add get_absolute_path method to context.models API

Given a model config or path (presumably to a model), returns the absolute path to the model.

Check the next few commits for use-case.

Author: psychedelicious

invokeai/app/services/shared/invocation_context.py

@@ -21,6 +21,7 @@
 from invokeai.app.util.step_callback import diffusion_step_callback
 from invokeai.backend.model_manager.config import (
     AnyModelConfig,
+    ModelConfigBase,
 )
 from invokeai.backend.model_manager.load.load_base import LoadedModel, LoadedModelWithoutConfig
 from invokeai.backend.model_manager.taxonomy import AnyModel, BaseModelType, ModelFormat, ModelType, SubModelType
@@ -543,6 +544,30 @@ def load_remote_model(
         self._util.signal_progress(f"Loading model {source}")
         return self._services.model_manager.load.load_model_from_path(model_path=model_path, loader=loader)
 
+    def get_absolute_path(self, config_or_path: AnyModelConfig | Path | str) -> Path:
+        """Gets the absolute path for a given model config or path.
+
+        For example, if the model's path is `flux/main/FLUX Dev.safetensors`, and the models path is
+        `/home/username/InvokeAI/models`, this method will return
+        `/home/username/InvokeAI/models/flux/main/FLUX Dev.safetensors`.
+
+        Args:
+            config_or_path: The model config or path.
+
+        Returns:
+            The absolute path to the model.
+        """
+
+        model_path = Path(config_or_path.path) if isinstance(config_or_path, ModelConfigBase) else Path(config_or_path)
+
+        if model_path.is_absolute():
+            return model_path.resolve()
+
+        base_models_path = self._services.configuration.models_path
+        joined_path = base_models_path / model_path
+        resolved_path = joined_path.resolve()
+        return resolved_path
+
 
 class ConfigInterface(InvocationContextInterface):
     def get(self) -> InvokeAIAppConfig: