Make embedding generation go through inference (#606)

This PR does the following:
1) adds the ability to generate embeddings in all supported inference
providers.
2) Moves all the memory providers to use the inference API and improved
the memory tests to setup the inference stack correctly and use the
embedding models

This is a merge from #589 and #598

llama_stack/providers/remote/inference/ollama/ollama.py

@@ -36,6 +36,7 @@ from llama_stack.providers.utils.inference.openai_compat import (
 from llama_stack.providers.utils.inference.prompt_adapter import (
     chat_completion_request_to_prompt,
     completion_request_to_prompt,
+    content_has_media,
     convert_image_media_to_url,
     request_has_media,
 )
@@ -321,9 +322,30 @@ class OllamaInferenceAdapter(Inference, ModelsProtocolPrivate):
         model_id: str,
         contents: List[InterleavedTextMedia],
     ) -> EmbeddingsResponse:
-        raise NotImplementedError()
+        model = await self.model_store.get_model(model_id)
+
+        assert all(
+            not content_has_media(content) for content in contents
+        ), "Ollama does not support media for embeddings"
+        response = await self.client.embed(
+            model=model.provider_resource_id,
+            input=[interleaved_text_media_as_str(content) for content in contents],
+        )
+        embeddings = response["embeddings"]
+
+        return EmbeddingsResponse(embeddings=embeddings)
 
     async def register_model(self, model: Model) -> Model:
+        # ollama does not have embedding models running. Check if the model is in list of available models.
+        if model.model_type == ModelType.embedding_model:
+            response = await self.client.list()
+            available_models = [m["model"] for m in response["models"]]
+            if model.provider_resource_id not in available_models:
+                raise ValueError(
+                    f"Model '{model.provider_resource_id}' is not available in Ollama. "
+                    f"Available models: {', '.join(available_models)}"
+                )
+            return model
         model = await self.register_helper.register_model(model)
         models = await self.client.ps()
         available_models = [m["model"] for m in models["models"]]