Amadeus Flight and Travel Search Tool (langchain-ai#7890)

## Background
With the addition on email and calendar tools, LangChain is continuing
to complete its functionality to automate business processes.

## Challenge
One of the pieces of business functionality that LangChain currently
doesn't have is the ability to search for flights and travel in order to
book business travel.

## Changes
This PR implements an integration with the
[Amadeus](https://developers.amadeus.com/) travel search API for
LangChain, enabling seamless search for flights with a single
authentication process.

## Who can review?
@hinthornw

## Appendix
@tsolakoua and @minjikarin, I utilized your
[amadeus-python](https://github.com/amadeus4dev/amadeus-python) library
extensively. Given the rising popularity of LangChain and similar AI
frameworks, the convergence of libraries like amadeus-python and tools
like this one is likely. So, I wanted to keep you updated on our
progress.

---------

Co-authored-by: Bagatur <[email protected]>

docs/extras/modules/agents/toolkits/amadeus.ipynb

@@ -0,0 +1,242 @@
+{
+ "cells": [
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Amadeus Toolkit\n",
+    "\n",
+    "This notebook walks you through connecting LangChain to the Amadeus travel information API\n",
+    "\n",
+    "To use this toolkit, you will need to set up your credentials explained in the [Amadeus for developers getting started overview](https://developers.amadeus.com/get-started/get-started-with-self-service-apis-335). Once you've received a AMADEUS_CLIENT_ID and AMADEUS_CLIENT_SECRET, you can input them as environmental variables below."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "!pip install --upgrade amadeus > /dev/null"
+   ]
+  },
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Assign Environmental Variables\n",
+    "\n",
+    "The toolkit will read the AMADEUS_CLIENT_ID and AMADEUS_CLIENT_SECRET environmental variables to authenticate the user so you need to set them here. You will also need to set your OPENAI_API_KEY to use the agent later."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Set environmental variables here\n",
+    "import os\n",
+    "\n",
+    "os.environ[\"AMADEUS_CLIENT_ID\"] = \"CLIENT_ID\"\n",
+    "os.environ[\"AMADEUS_CLIENT_SECRET\"] = \"CLIENT_SECRET\"\n",
+    "os.environ[\"OPENAI_API_KEY\"] = \"API_KEY\""
+   ]
+  },
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Create the Amadeus Toolkit and Get Tools\n",
+    "\n",
+    "To start, you need to create the toolkit, so you can access its tools later."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "from langchain.agents.agent_toolkits.amadeus.toolkit import AmadeusToolkit\n",
+    "\n",
+    "toolkit = AmadeusToolkit()\n",
+    "tools = toolkit.get_tools()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Use Amadeus Toolkit within an Agent"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "from langchain import OpenAI\n",
+    "from langchain.agents import initialize_agent, AgentType"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [],
+   "source": [
+    "llm = OpenAI(temperature=0)\n",
+    "agent = initialize_agent(\n",
+    "    tools=tools,\n",
+    "    llm=llm,\n",
+    "    verbose=False,\n",
+    "    agent=AgentType.STRUCTURED_CHAT_ZERO_SHOT_REACT_DESCRIPTION,\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'The closest airport to Cali, Colombia is Alfonso Bonilla Aragón International Airport (CLO).'"
+      ]
+     },
+     "execution_count": 6,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "agent.run(\"What is the name of the airport in Cali, Colombia?\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "tags": []
+   },
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'The cheapest flight on August 23, 2023 leaving Dallas, Texas before noon to Lincoln, Nebraska has a departure time of 16:42 and a total price of 276.08 EURO.'"
+      ]
+     },
+     "execution_count": 7,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "agent.run(\n",
+    "    \"What is the departure time of the cheapest flight on August 23, 2023 leaving Dallas, Texas before noon to Lincoln, Nebraska?\"\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'The earliest flight on August 23, 2023 leaving Dallas, Texas to Lincoln, Nebraska lands in Lincoln, Nebraska at 16:07.'"
+      ]
+     },
+     "execution_count": 8,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "agent.run(\n",
+    "    \"At what time does earliest flight on August 23, 2023 leaving Dallas, Texas to Lincoln, Nebraska land in Nebraska?\"\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'The cheapest flight between Portland, Oregon to Dallas, TX on October 3, 2023 is a Spirit Airlines flight with a total price of 84.02 EURO and a total travel time of 8 hours and 43 minutes.'"
+      ]
+     },
+     "execution_count": 9,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "agent.run(\n",
+    "    \"What is the full travel time for the cheapest flight between Portland, Oregon to Dallas, TX on October 3, 2023?\"\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 10,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "'Dear Paul,\\n\\nI am writing to request that you book the earliest flight from DFW to DCA on Aug 28, 2023. The flight details are as follows:\\n\\nFlight 1: DFW to ATL, departing at 7:15 AM, arriving at 10:25 AM, flight number 983, carrier Delta Air Lines\\nFlight 2: ATL to DCA, departing at 12:15 PM, arriving at 2:02 PM, flight number 759, carrier Delta Air Lines\\n\\nThank you for your help.\\n\\nSincerely,\\nSantiago'"
+      ]
+     },
+     "execution_count": 10,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "agent.run(\n",
+    "    \"Please draft a concise email from Santiago to Paul, Santiago's travel agent, asking him to book the earliest flight from DFW to DCA on Aug 28, 2023. Include all flight details in the email.\"\n",
+    ")"
+   ]
+  }
+ ],
+ "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": "3.11.4"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}

langchain/agents/agent_toolkits/__init__.py

@@ -1,5 +1,5 @@
 """Agent toolkits."""
-
+from langchain.agents.agent_toolkits.amadeus.toolkit import AmadeusToolkit
 from langchain.agents.agent_toolkits.azure_cognitive_services.toolkit import (
     AzureCognitiveServicesToolkit,
 )
@@ -39,6 +39,7 @@
 from langchain.agents.agent_toolkits.zapier.toolkit import ZapierToolkit
 
 __all__ = [
+    "AmadeusToolkit",
     "create_json_agent",
     "create_sql_agent",
     "create_openapi_agent",

langchain/agents/agent_toolkits/amadeus/toolkit.py

@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, List
+
+from pydantic import Field
+
+from langchain.agents.agent_toolkits.base import BaseToolkit
+from langchain.tools import BaseTool
+from langchain.tools.amadeus.closest_airport import AmadeusClosestAirport
+from langchain.tools.amadeus.flight_search import AmadeusFlightSearch
+from langchain.tools.amadeus.utils import authenticate
+
+if TYPE_CHECKING:
+    from amadeus import Client
+
+
+class AmadeusToolkit(BaseToolkit):
+    """Toolkit for interacting with Office365."""
+
+    client: Client = Field(default_factory=authenticate)
+
+    class Config:
+        """Pydantic config."""
+
+        arbitrary_types_allowed = True
+
+    def get_tools(self) -> List[BaseTool]:
+        """Get the tools in the toolkit."""
+        return [
+            AmadeusClosestAirport(),
+            AmadeusFlightSearch(),
+        ]

langchain/tools/amadeus/__init__.py

@@ -0,0 +1,9 @@
+"""Amadeus tools."""
+
+from langchain.tools.amadeus.closest_airport import AmadeusClosestAirport
+from langchain.tools.amadeus.flight_search import AmadeusFlightSearch
+
+__all__ = [
+    "AmadeusClosestAirport",
+    "AmadeusFlightSearch",
+]

langchain/tools/amadeus/base.py

@@ -0,0 +1,16 @@
+"""Base class for Amadeus tools."""
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+from pydantic import Field
+
+from langchain.tools.amadeus.utils import authenticate
+from langchain.tools.base import BaseTool
+
+if TYPE_CHECKING:
+    from amadeus import Client
+
+
+class AmadeusBaseTool(BaseTool):
+    client: Client = Field(default_factory=authenticate)

langchain/tools/amadeus/closest_airport.py

@@ -0,0 +1,63 @@
+from typing import Optional, Type
+
+from pydantic import BaseModel, Field
+
+from langchain.callbacks.manager import (
+    AsyncCallbackManagerForToolRun,
+    CallbackManagerForToolRun,
+)
+from langchain.chains import LLMChain
+from langchain.chat_models import ChatOpenAI
+from langchain.tools.amadeus.base import AmadeusBaseTool
+
+
+class ClosestAirportSchema(BaseModel):
+    location: str = Field(
+        description=(
+            " The location for which you would like to find the nearest airport "
+            " along with optional details such as country, state, region, or "
+            " province, allowing for easy processing and identification of "
+            " the closest airport. Examples of the format are the following:\n"
+            " Cali, Colombia\n "
+            " Lincoln, Nebraska, United States\n"
+            " New York, United States\n"
+            " Sydney, New South Wales, Australia\n"
+            " Rome, Lazio, Italy\n"
+            " Toronto, Ontario, Canada\n"
+        )
+    )
+
+
+class AmadeusClosestAirport(AmadeusBaseTool):
+    name: str = "closest_airport"
+    description: str = (
+        "Use this tool to find the closest airport to a particular location."
+    )
+    args_schema: Type[ClosestAirportSchema] = ClosestAirportSchema
+
+    def _run(
+        self,
+        location: str,
+        run_manager: Optional[CallbackManagerForToolRun] = None,
+    ) -> str:
+        template = (
+            " What is the nearest airport to {location}? Please respond with the "
+            " airport's International Air Transport Association (IATA) Location "
+            ' Identifier in the following JSON format. JSON: "iataCode": "IATA '
+            ' Location Identifier" '
+        )
+
+        llm = ChatOpenAI(temperature=0)
+
+        llm_chain = LLMChain.from_string(llm=llm, template=template)
+
+        output = llm_chain.run(location=location)
+
+        return output
+
+    async def _arun(
+        self,
+        location: str,
+        run_manager: Optional[AsyncCallbackManagerForToolRun] = None,
+    ) -> str:
+        raise NotImplementedError(f"The tool {self.name} does not support async yet.")