template: Add Bedrock JCVD template (#14480)

This PR adds a simple LangChain template that uses [Anthropic's Claude
on Amazon Bedrock ⛰️](https://aws.amazon.com/bedrock/claude/) to behave
like JCVD.

---------

Co-authored-by: Erick Friis <[email protected]>

templates/bedrock-jcvd/README.md

@@ -0,0 +1,81 @@
+# Bedrock JCVD 🕺🥋
+
+## Overview
+
+LangChain template that uses [Anthropic's Claude on Amazon Bedrock](https://aws.amazon.com/bedrock/claude/) to behave like JCVD.
+
+> I am the Fred Astaire of Chatbots! 🕺
+
+'![JCVD](https://media.tenor.com/CVp9l7g3axwAAAAj/jean-claude-van-damme-jcvd.gif)
+
+## Environment Setup
+
+### AWS Credentials
+
+This template uses [Boto3](https://boto3.amazonaws.com/v1/documentation/api/latest/index.html), the AWS SDK for Python, to call [Amazon Bedrock](https://aws.amazon.com/bedrock/). You **must** configure both AWS credentials *and* an AWS Region in order to make requests. 
+
+> For information on how to do this, see [AWS Boto3 documentation](https://boto3.amazonaws.com/v1/documentation/api/latest/guide/credentials.html) (Developer Guide > Credentials).
+
+### Foundation Models
+
+By default, this template uses [Anthropic's Claude v2](https://aws.amazon.com/about-aws/whats-new/2023/08/claude-2-foundation-model-anthropic-amazon-bedrock/) (`anthropic.claude-v2`).
+
+> To request access to a specific model, check out the [Amazon Bedrock User Guide](https://docs.aws.amazon.com/bedrock/latest/userguide/model-access.html) (Model access)
+
+To use a different model, set the environment variable `BEDROCK_JCVD_MODEL_ID`. A list of base models is available in the [Amazon Bedrock User Guide](https://docs.aws.amazon.com/bedrock/latest/userguide/model-ids-arns.html) (Use the API > API operations > Run inference > Base Model IDs).
+
+> The full list of available models (including base and [custom models](https://docs.aws.amazon.com/bedrock/latest/userguide/custom-models.html)) is available in the [Amazon Bedrock Console](https://docs.aws.amazon.com/bedrock/latest/userguide/using-console.html) under **Foundation Models** or by calling [`aws bedrock list-foundation-models`](https://docs.aws.amazon.com/cli/latest/reference/bedrock/list-foundation-models.html).
+
+## Usage
+
+To use this package, you should first have the LangChain CLI installed:
+
+```shell
+pip install -U langchain-cli
+```
+
+To create a new LangChain project and install this as the only package, you can do:
+
+```shell
+langchain app new my-app --package bedrock-jcvd
+```
+
+If you want to add this to an existing project, you can just run:
+
+```shell
+langchain app add bedrock-jcvd
+```
+
+And add the following code to your `server.py` file:
+```python
+from bedrock_jcvd import chain as bedrock_jcvd_chain
+
+add_routes(app, bedrock_jcvd_chain, path="/bedrock-jcvd")
+```
+
+(Optional) Let's now configure LangSmith. 
+LangSmith will help us trace, monitor and debug LangChain applications. 
+LangSmith is currently in private beta, you can sign up [here](https://smith.langchain.com/). 
+If you don't have access, you can skip this section
+
+
+```shell
+export LANGCHAIN_TRACING_V2=true
+export LANGCHAIN_API_KEY=<your-api-key>
+export LANGCHAIN_PROJECT=<your-project>  # if not specified, defaults to "default"
+```
+
+If you are inside this directory, then you can spin up a LangServe instance directly by:
+
+```shell
+langchain serve
+```
+
+This will start the FastAPI app with a server is running locally at 
+[http://localhost:8000](http://localhost:8000)
+
+We can see all templates at [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs).
+
+We can also access the playground at [http://127.0.0.1:8000/bedrock-jcvd/playground](http://127.0.0.1:8000/bedrock-jcvd/playground)
+
+![JCVD Playground](jcvd_langserve.png)

templates/bedrock-jcvd/bedrock_jcvd/chain.py

@@ -0,0 +1,47 @@
+import os
+
+from langchain.chat_models import BedrockChat
+from langchain.prompts import ChatPromptTemplate
+from langchain.schema.runnable import ConfigurableField
+
+# For a description of each inference parameter, see
+# https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-claude.html
+_model_kwargs = {
+    "temperature": float(os.getenv("BEDROCK_JCVD_TEMPERATURE", "0.1")),
+    "top_p": float(os.getenv("BEDROCK_JCVD_TOP_P", "1")),
+    "top_k": int(os.getenv("BEDROCK_JCVD_TOP_K", "250")),
+    "max_tokens_to_sample": int(os.getenv("BEDROCK_JCVD_MAX_TOKENS_TO_SAMPLE", "300")),
+}
+
+# Full list of base model IDs is available at
+# https://docs.aws.amazon.com/bedrock/latest/userguide/model-ids-arns.html
+_model_alts = {
+    "claude_2_1": BedrockChat(
+        model_id="anthropic.claude-v2:1", model_kwargs=_model_kwargs
+    ),
+    "claude_1": BedrockChat(model_id="anthropic.claude-v1", model_kwargs=_model_kwargs),
+    "claude_instant_1": BedrockChat(
+        model_id="anthropic.claude-instant-v1", model_kwargs=_model_kwargs
+    ),
+}
+
+# For some tips on how to construct effective prompts for Claude,
+# check out Anthropic's Claude Prompt Engineering deck (Bedrock edition)
+# https://docs.google.com/presentation/d/1tjvAebcEyR8la3EmVwvjC7PHR8gfSrcsGKfTPAaManw
+_prompt = ChatPromptTemplate.from_messages(
+    [
+        ("human", "You are JCVD. {input}"),
+    ]
+)
+
+_model = BedrockChat(
+    model_id="anthropic.claude-v2", model_kwargs=_model_kwargs
+).configurable_alternatives(
+    which=ConfigurableField(
+        id="model", name="Model", description="The model that will be used"
+    ),
+    default_key="claude_2",
+    **_model_alts,
+)
+
+chain = _prompt | _model