27 Mar 2024

This code-along will focus on a simple RAG implementation that runs locally on your machine using Ollama. In addition to installing the dependencies below, choose a document with text content that you want to chat with the model about, and store it as a PDF in the documents directory. Haystack has support for other document converters as well, although you may need to install additional dependencies. This code-along will assume you're using a PDF.

• Python 3.11+ (Rye will automatically use 3.11 by default; see below)
• VS Code (https://code.visualstudio.com/) with the Python extension (search in Extensions in the side bar)
• Rye (https://rye-up.com/), to manage the project’s Python third-party dependencies and Python interpreter version. For Windows users, you’ll likely want to use the 64-bit installer.
• Ollama (https://ollama.com/)

First, clone this repo, and open the ollama-rag.code-workspace file in VS Code.

From the terminal in VS Code, install the Python dependencies using Rye:

$ rye sync

This will install the following Python dependencies in a virtual environment: gradio ollama haystack-ai ollama-haystack pypdf. If VS Code prompts you to select the new environment for the workspace, say yes.

Next, use Ollama to pull down the models you want to use. Do these two, at least:

$ ollama pull llama2
$ ollama pull nomic-embed-text

Test it out by chatting with it on the command line:

$ ollama run llama2

If you’d like, check out the supported models at https://ollama.com/library and pull any that you’d like to try. Unless you have a powerful GPU, it’s recommended that you use models in the 7b-parameter and under category. If your machine only supports running on CPU and you want to speed that up, there are smaller models such as gemma:2b that you can try, although the performance will not be as good. In general, the more parameters the model has, the better its accuracy, the more resources it requires, and the more slowly it runs. I’ll be doing the code-along with the llama2:7b model, but feel free to experiment and use what you like best!