langchain/templates/rag-astradb/README.md

# rag-astradb

This template will perform RAG using Astra DB (`AstraDB` vector store class)

## Environment Setup

An [Astra DB](https://astra.datastax.com) database is required; free tier is fine.

- You need the database **API endpoint** (such as `https://0123...-us-east1.apps.astra.datastax.com`) ...
- ... and a **token** (`AstraCS:...`).

Also, an **OpenAI API Key** is required. _Note that out-of-the-box this demo supports OpenAI only, unless you tinker with the code._

Provide the connection parameters and secrets through environment variables. Please refer to `.env.template` for the variable names.

## Usage

To use this package, you should first have the LangChain CLI installed:

```shell
pip install -U "langchain-cli[serve]"
```

To create a new LangChain project and install this as the only package, you can do:

```shell
langchain app new my-app --package rag-astradb
```

If you want to add this to an existing project, you can just run:

```shell
langchain app add rag-astradb
```

And add the following code to your `server.py` file:
```python
from astradb_entomology_rag import chain as astradb_entomology_rag_chain

add_routes(app, astradb_entomology_rag_chain, path="/rag-astradb")
```

(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 access the playground at [http://127.0.0.1:8000/rag-astradb/playground](http://127.0.0.1:8000/rag-astradb/playground)  

We can access the template from code with:

```python
from langserve.client import RemoteRunnable

runnable = RemoteRunnable("http://localhost:8000/rag-astradb")
```

## Reference

Stand-alone repo with LangServe chain: [here](https://github.com/hemidactylus/langserve_astradb_entomology_rag).