add metal retriever (#2244)

docs/modules/indexes/retrievers/examples/metal.ipynb

@@ -0,0 +1,156 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "9fc6205b",
+   "metadata": {},
+   "source": [
+    "# Metal\n",
+    "\n",
+    "This notebook shows how to use [Metal's](https://docs.getmetal.io/introduction) retriever.\n",
+    "\n",
+    "First, you will need to sign up for Metal and get an API key. You can do so [here](https://docs.getmetal.io/misc-create-app)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "1a737220",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# !pip install metal_sdk"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "id": "b1bb478f",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from metal_sdk.metal import Metal\n",
+    "API_KEY = \"\"\n",
+    "CLIENT_ID = \"\"\n",
+    "APP_ID = \"\"\n",
+    "\n",
+    "metal = Metal(API_KEY, CLIENT_ID, APP_ID);\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "ae3c3d16",
+   "metadata": {},
+   "source": [
+    "## Ingest Documents\n",
+    "\n",
+    "You only need to do this if you haven't already set up an index"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "f0425fa0",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "{'data': {'id': '642739aa7559b026b4430e42',\n",
+       "  'text': 'foo',\n",
+       "  'createdAt': '2023-03-31T19:51:06.748Z'}}"
+      ]
+     },
+     "execution_count": 8,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "metal.index( {\"text\": \"foo1\"})\n",
+    "metal.index( {\"text\": \"foo\"})"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "944e172b",
+   "metadata": {},
+   "source": [
+    "## Query\n",
+    "\n",
+    "Now that our index is set up, we can set up a retriever and start querying it."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "id": "d0e6f506",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from langchain.retrievers import MetalRetriever"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "id": "f381f642",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "retriever = MetalRetriever(metal, params={\"limit\": 2})"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 11,
+   "id": "20ae1a74",
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "[Document(page_content='foo1', metadata={'dist': '1.19209289551e-07', 'id': '642739a17559b026b4430e40', 'createdAt': '2023-03-31T19:50:57.853Z'}),\n",
+       " Document(page_content='foo1', metadata={'dist': '4.05311584473e-06', 'id': '642738f67559b026b4430e3c', 'createdAt': '2023-03-31T19:48:06.769Z'})]"
+      ]
+     },
+     "execution_count": 11,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "retriever.get_relevant_documents(\"foo1\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "1d5a5088",
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 (ipykernel)",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.9.1"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

langchain/retrievers/__init__.py

@@ -1,4 +1,5 @@
 from langchain.retrievers.chatgpt_plugin_retriever import ChatGPTPluginRetriever
+from langchain.retrievers.metal import MetalRetriever
 from langchain.retrievers.remote_retriever import RemoteLangChainRetriever
 
-__all__ = ["ChatGPTPluginRetriever", "RemoteLangChainRetriever"]
+__all__ = ["ChatGPTPluginRetriever", "RemoteLangChainRetriever", "MetalRetriever"]

langchain/retrievers/metal.py

@@ -0,0 +1,27 @@
+from typing import Any, List, Optional
+
+from langchain.schema import BaseRetriever, Document
+
+
+class MetalRetriever(BaseRetriever):
+    def __init__(self, client: Any, params: Optional[dict] = None):
+        from metal_sdk.metal import Metal
+
+        if not isinstance(client, Metal):
+            raise ValueError(
+                "Got unexpected client, should be of type metal_sdk.metal.Metal. "
+                f"Instead, got {type(client)}"
+            )
+        self.client: Metal = client
+        self.params = params or {}
+
+    def get_relevant_documents(self, query: str) -> List[Document]:
+        results = self.client.search({"text": query}, **self.params)
+        final_results = []
+        for r in results["data"]:
+            metadata = {k: v for k, v in r.items() if k != "text"}
+            final_results.append(Document(page_content=r["text"], metadata=metadata))
+        return final_results
+
+    async def aget_relevant_documents(self, query: str) -> List[Document]:
+        raise NotImplementedError