feat(llm): Add openailike llm mode (#1447)

This mode behaves the same as the openai mode, except that it allows setting custom models not
supported by OpenAI. It can be used with any tool that serves models from an OpenAI compatible API.

Implements #1424

Author: mchill

fern/docs/pages/manual/llms.mdx

@@ -37,6 +37,7 @@ llm:
   mode: openai
 
 openai:
+  api_base: <openai-api-base-url> # Defaults to https://api.openai.com/v1
   api_key: <your_openai_api_key>  # You could skip this configuration and use the OPENAI_API_KEY env var instead
   model: <openai_model_to_use> # Optional model to use. Default is "gpt-3.5-turbo"
                                # Note: Open AI Models are listed here: https://platform.openai.com/docs/models
@@ -55,6 +56,24 @@ Navigate to http://localhost:8001 to use the Gradio UI or to http://localhost:80
 You'll notice the speed and quality of response is higher, given you are using OpenAI's servers for the heavy
 computations.
 
+### Using OpenAI compatible API
+
+Many tools, including [LocalAI](https://localai.io/) and [vLLM](https://docs.vllm.ai/en/latest/),
+support serving local models with an OpenAI compatible API. Even when overriding the `api_base`,
+using the `openai` mode doesn't allow you to use custom models. Instead, you should use the `openailike` mode:
+
+```yaml
+llm:
+  mode: openailike
+```
+
+This mode uses the same settings as the `openai` mode.
+
+As an example, you can follow the [vLLM quickstart guide](https://docs.vllm.ai/en/latest/getting_started/quickstart.html#openai-compatible-server)
+to run an OpenAI compatible server. Then, you can run PrivateGPT using the `settings-vllm.yaml` profile:
+
+`PGPT_PROFILES=vllm make run`
+
 ### Using AWS Sagemaker
 
 For a fully private & performant setup, you can choose to have both your LLM and Embeddings model deployed using Sagemaker.
@@ -82,4 +101,4 @@ or
 `PGPT_PROFILES=sagemaker poetry run python -m private_gpt`
 
 When the server is started it will print a log *Application startup complete*.
-Navigate to http://localhost:8001 to use the Gradio UI or to http://localhost:8001/docs (API section) to try the API.
+Navigate to http://localhost:8001 to use the Gradio UI or to http://localhost:8001/docs (API section) to try the API.

private_gpt/components/llm/llm_component.py

@@ -62,7 +62,21 @@ def __init__(self, settings: Settings) -> None:
 
                 openai_settings = settings.openai
                 self.llm = OpenAI(
-                    api_key=openai_settings.api_key, model=openai_settings.model
+                    api_base=openai_settings.api_base,
+                    api_key=openai_settings.api_key,
+                    model=openai_settings.model,
+                )
+            case "openailike":
+                from llama_index.llms import OpenAILike
+
+                openai_settings = settings.openai
+                self.llm = OpenAILike(
+                    api_base=openai_settings.api_base,
+                    api_key=openai_settings.api_key,
+                    model=openai_settings.model,
+                    is_chat_model=True,
+                    max_tokens=None,
+                    api_version="",
                 )
             case "mock":
                 self.llm = MockLLM()

private_gpt/settings/settings.py

@@ -81,7 +81,7 @@ class DataSettings(BaseModel):
 
 
 class LLMSettings(BaseModel):
-    mode: Literal["local", "openai", "sagemaker", "mock"]
+    mode: Literal["local", "openai", "openailike", "sagemaker", "mock"]
     max_new_tokens: int = Field(
         256,
         description="The maximum number of token that the LLM is authorized to generate in one completion.",
@@ -156,6 +156,10 @@ class SagemakerSettings(BaseModel):
 
 
 class OpenAISettings(BaseModel):
+    api_base: str = Field(
+        None,
+        description="Base URL of OpenAI API. Example: 'https://api.openai.com/v1'.",
+    )
     api_key: str
     model: str = Field(
         "gpt-3.5-turbo",

settings-vllm.yaml

@@ -0,0 +1,14 @@
+llm:
+  mode: openailike
+
+embedding:
+  mode: local
+  ingest_mode: simple
+
+local:
+  embedding_hf_model_name: BAAI/bge-small-en-v1.5
+
+openai:
+  api_base: http://localhost:8000/v1
+  api_key: EMPTY
+  model: facebook/opt-125m