implement embedding generation in supported inference providers (#589)

This PR adds the ability to generate embeddings in all supported
inference providers.

```
pytest -v -s llama_stack/providers/tests/inference/test_embeddings.py -k "bedrock" --inference-model="amazon.titan-embed-text-v2:0"  --env EMBEDDING_DIMENSION=1024

 pytest -v -s -k "vllm"  --inferrence-model="intfloat/e5-mistral-7b-instruct"  llama_stack/providers/tests/inference/test_embeddings.py --env EMBEDDING_DIMENSION=4096  --env VLLM_URL="http://localhost:9798/v1"

pytest -v -s --inference-model="nomic-ai/nomic-embed-text-v1.5"  llama_stack/providers/tests/inference/test_embeddings.py  -k "fireworks"  --env FIREWORKS_API_KEY=<API_KEY>--env EMBEDDING_DIMENSION=128

pytest -v -s --inference-model="togethercomputer/m2-bert-80M-2k-retrieval"  llama_stack/providers/tests/inference/test_embeddings.py  -k "together"  --env TOGETHER_API_KEY=<API_KEY>--env EMBEDDING_DIMENSION=768

pytest -v -s -k "ollama"  --inference-model="all-minilm:v8"  llama_stack/providers/tests/inference/test_embeddings.py --env EMBEDDING_DIMENSION=384

 torchrun $CONDA_PREFIX/bin/pytest -v -s -k "meta_reference" --inference-model="sentence-transformers/all-MiniLM-L6-v2"  llama_stack/providers/tests/inference/test_embeddings.py --env EMBEDDING_DIMENSION=384

```

llama_stack/providers/inline/inference/meta_reference/inference.py

@@ -16,12 +16,14 @@ from llama_models.llama3.api.datatypes import *  # noqa: F403
 from llama_stack.providers.utils.inference.model_registry import build_model_alias
 from llama_stack.apis.inference import *  # noqa: F403
 from llama_stack.providers.datatypes import ModelsProtocolPrivate
+from llama_stack.providers.utils.inference.embedding_mixin import (
+    SentenceTransformerEmbeddingMixin,
+)
 from llama_stack.providers.utils.inference.model_registry import ModelRegistryHelper
 from llama_stack.providers.utils.inference.prompt_adapter import (
     convert_image_media_to_url,
     request_has_media,
 )
-
 from .config import MetaReferenceInferenceConfig
 from .generation import Llama
 from .model_parallel import LlamaModelParallelGenerator
@@ -32,12 +34,17 @@ log = logging.getLogger(__name__)
 SEMAPHORE = asyncio.Semaphore(1)
 
 
-class MetaReferenceInferenceImpl(Inference, ModelRegistryHelper, ModelsProtocolPrivate):
+class MetaReferenceInferenceImpl(
+    SentenceTransformerEmbeddingMixin,
+    Inference,
+    ModelsProtocolPrivate,
+):
     def __init__(self, config: MetaReferenceInferenceConfig) -> None:
         self.config = config
         model = resolve_model(config.model)
-        ModelRegistryHelper.__init__(
-            self,
+        if model is None:
+            raise RuntimeError(f"Unknown model: {config.model}, Run `llama model list`")
+        self.model_registry_helper = ModelRegistryHelper(
             [
                 build_model_alias(
                     model.descriptor(),
@@ -45,8 +52,6 @@ class MetaReferenceInferenceImpl(Inference, ModelRegistryHelper, ModelsProtocolP
                 )
             ],
         )
-        if model is None:
-            raise RuntimeError(f"Unknown model: {config.model}, Run `llama model list`")
         self.model = model
         # verify that the checkpoint actually is for this model lol
 
@@ -76,6 +81,12 @@ class MetaReferenceInferenceImpl(Inference, ModelRegistryHelper, ModelsProtocolP
     async def unregister_model(self, model_id: str) -> None:
         pass
 
+    async def register_model(self, model: Model) -> Model:
+        model = await self.model_registry_helper.register_model(model)
+        if model.model_type == ModelType.embedding_model:
+            self._load_sentence_transformer_model(model.provider_resource_id)
+        return model
+
     async def completion(
         self,
         model_id: str,
@@ -394,13 +405,6 @@ class MetaReferenceInferenceImpl(Inference, ModelRegistryHelper, ModelsProtocolP
             for x in impl():
                 yield x
 
-    async def embeddings(
-        self,
-        model_id: str,
-        contents: List[InterleavedTextMedia],
-    ) -> EmbeddingsResponse:
-        raise NotImplementedError()
-
 
 async def request_with_localized_media(
     request: Union[ChatCompletionRequest, CompletionRequest],

llama_stack/providers/inline/inference/sentence_transformers/__init__.py

@@ -0,0 +1,20 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from llama_stack.providers.inline.inference.sentence_transformers.config import (
+    SentenceTransformersInferenceConfig,
+)
+
+
+async def get_provider_impl(
+    config: SentenceTransformersInferenceConfig,
+    _deps,
+):
+    from .sentence_transformers import SentenceTransformersInferenceImpl
+
+    impl = SentenceTransformersInferenceImpl(config)
+    await impl.initialize()
+    return impl

llama_stack/providers/inline/inference/sentence_transformers/config.py

@@ -0,0 +1,10 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from pydantic import BaseModel
+
+
+class SentenceTransformersInferenceConfig(BaseModel): ...

llama_stack/providers/inline/inference/sentence_transformers/sentence_transformers.py

@@ -0,0 +1,74 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+import logging
+from typing import AsyncGenerator, List, Optional, Union
+
+from llama_stack.apis.inference import (
+    CompletionResponse,
+    Inference,
+    LogProbConfig,
+    Message,
+    ResponseFormat,
+    SamplingParams,
+    ToolChoice,
+    ToolDefinition,
+    ToolPromptFormat,
+)
+from llama_stack.providers.datatypes import Model, ModelsProtocolPrivate
+from llama_stack.providers.utils.inference.embedding_mixin import (
+    SentenceTransformerEmbeddingMixin,
+)
+from .config import SentenceTransformersInferenceConfig
+
+log = logging.getLogger(__name__)
+
+
+class SentenceTransformersInferenceImpl(
+    SentenceTransformerEmbeddingMixin,
+    Inference,
+    ModelsProtocolPrivate,
+):
+    def __init__(self, config: SentenceTransformersInferenceConfig) -> None:
+        self.config = config
+
+    async def initialize(self) -> None:
+        pass
+
+    async def shutdown(self) -> None:
+        pass
+
+    async def register_model(self, model: Model) -> None:
+        _ = self._load_sentence_transformer_model(model.provider_resource_id)
+        return model
+
+    async def unregister_model(self, model_id: str) -> None:
+        pass
+
+    async def completion(
+        self,
+        model_id: str,
+        content: str,
+        sampling_params: Optional[SamplingParams] = SamplingParams(),
+        response_format: Optional[ResponseFormat] = None,
+        stream: Optional[bool] = False,
+        logprobs: Optional[LogProbConfig] = None,
+    ) -> Union[CompletionResponse, AsyncGenerator]:
+        raise ValueError("Sentence transformers don't support completion")
+
+    async def chat_completion(
+        self,
+        model_id: str,
+        messages: List[Message],
+        sampling_params: Optional[SamplingParams] = SamplingParams(),
+        response_format: Optional[ResponseFormat] = None,
+        tools: Optional[List[ToolDefinition]] = None,
+        tool_choice: Optional[ToolChoice] = ToolChoice.auto,
+        tool_prompt_format: Optional[ToolPromptFormat] = ToolPromptFormat.json,
+        stream: Optional[bool] = False,
+        logprobs: Optional[LogProbConfig] = None,
+    ) -> AsyncGenerator:
+        raise ValueError("Sentence transformers don't support chat completion")