Documenting AWS Bedrock support with Anthropic Claude (#195)

* working on documenting AWS Bedrock support with Anthropic

* added documentation and helper functions

* removing unused functions

* cleaning up

lib/chat_models/chat_anthropic.ex

@@ -53,6 +53,26 @@ defmodule LangChain.ChatModels.ChatAnthropic do
         tool_choice: %{"type" => "tool", "name" => "get_weather"}
       })
 
+  ## AWS Bedrock Support
+
+  Anthropic Claude is supported in [AWS Bedrock](https://docs.aws.amazon.com/bedrock/latest/userguide/what-is-bedrock.html).
+
+  To configure `ChatAnthropic` for use on AWS Bedrock:
+
+  1. Request [Model Access](https://console.aws.amazon.com/bedrock/home?#/modelaccess) to get access to the Anthropic models you intend to use.
+  2. Using your AWS Console, create an Access Key for your application.
+  3. Set the key values in your `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` ENVs.
+  4. Get the Model ID for the model you intend to use. [Base Models](https://console.aws.amazon.com/bedrock/home?#/models)
+  5. Refer to `LangChain.Utils.BedrockConfig` for setting up the Bedrock authentication credentials for your environment.
+  6. Setup your ChatAnthropic similar to the following:
+
+      alias LangChain.ChatModels.ChatAnthropic
+
+      ChatAnthropic.new!(%{
+        model: "anthropic.claude-3-5-sonnet-20241022-v2:0",
+        bedrock: BedrockConfig.from_application_env!()
+      })
+
   """
   use Ecto.Schema
   require Logger

lib/utils/bedrock_config.ex

@@ -1,9 +1,45 @@
 defmodule LangChain.Utils.BedrockConfig do
   @moduledoc """
   Configuration for AWS Bedrock.
+
+  ## Examples
+
+  For applications hosted in AWS, [ExAws](https://hex.pm/packages/ex_aws) caches
+  temporary credentials (when running on AWS), so in the credentials function
+  you can pull the current cached credentials from `ExAws`.
+
+      ChatAnthropic.new!(%{
+        model: "anthropic.claude-3-5-sonnet-20241022-v2:0",
+        bedrock: %{
+          credentials: fn ->
+            ExAws.Config.new(:s3)
+            |> Map.take([:access_key_id, :secret_access_key])
+            |> Map.to_list()
+          end,
+          region: "us-west-2"
+        }
+      })
+
+  For applications hosted anywhere, you can configure the Bedrock settings into
+  the LangChain config like this (recommended for `config/runtime.exs`):
+
+      config :langchain,
+        aws_access_key_id: System.fetch_env!("AWS_ACCESS_KEY_ID"),
+        aws_secret_access_key: System.fetch_env!("AWS_SECRET_ACCESS_KEY"),
+        aws_region: System.get_env("AWS_REGION", "us-west-1")
+
+  Then, when you want to later use a Bedrock Anthropic model, this is will load
+  it:
+
+        ChatAnthropic.new!(%{
+          model: "anthropic.claude-3-5-sonnet-20241022-v2:0",
+          bedrock: BedrockConfig.from_application_env!()
+        })
+
   """
   use Ecto.Schema
   import Ecto.Changeset
+  alias __MODULE__
 
   @primary_key false
   embedded_schema do
@@ -14,23 +50,51 @@ defmodule LangChain.Utils.BedrockConfig do
     field :anthropic_version, :string, default: "bedrock-2023-05-31"
   end
 
+  @type t :: %BedrockConfig{}
+
+  @create_fields [:credentials, :region, :anthropic_version]
+  @required_fields @create_fields
+
   def changeset(bedrock, attrs) do
     bedrock
-    |> cast(attrs, [:credentials, :region, :anthropic_version])
-    |> validate_required([:credentials, :region, :anthropic_version])
+    |> cast(attrs, @create_fields)
+    |> validate_required(@required_fields)
   end
 
-  def aws_sigv4_opts(%__MODULE__{} = bedrock) do
+  def aws_sigv4_opts(%BedrockConfig{} = bedrock) do
     Keyword.merge(bedrock.credentials.(),
       region: bedrock.region,
       service: :bedrock
     )
   end
 
-  def url(%__MODULE__{region: region}, model: model, stream: stream) do
+  def url(%BedrockConfig{region: region}, model: model, stream: stream) do
     "https://bedrock-runtime.#{region}.amazonaws.com/model/#{model}/#{action(stream: stream)}"
   end
 
   defp action(stream: true), do: "invoke-with-response-stream"
   defp action(stream: false), do: "invoke"
+
+  @doc """
+  Loads the Bedrock config settings from the previously configured Application settings.
+
+  `config/runtime.exs`:
+
+      config :langchain,
+        aws_access_key_id: System.fetch_env!("AWS_ACCESS_KEY_ID"),
+        aws_secret_access_key: System.fetch_env!("AWS_SECRET_ACCESS_KEY"),
+        aws_region: System.get_env("AWS_REGION", "us-west-1")
+
+  """
+  def from_application_env!() do
+    %{
+      credentials: fn ->
+        [
+          access_key_id: Application.fetch_env!(:langchain, :aws_access_key_id),
+          secret_access_key: Application.fetch_env!(:langchain, :aws_secret_access_key)
+        ]
+      end,
+      region: Application.fetch_env!(:langchain, :aws_region)
+    }
+  end
 end