Introduction
Within the second a part of our collection on constructing a RAG software on a Raspberry Pi, we’ll increase on the inspiration we laid within the first half, the place we created and examined the core pipeline. Within the first half, we created the core pipeline and examined it to make sure all the things labored as anticipated. Now, we’re going to take issues a step additional by constructing a FastAPI software to serve our RAG pipeline and making a Reflex app to present customers a easy and interactive solution to entry it. This half will information you thru organising the FastAPI back-end, designing the front-end with Reflex, and getting all the things up and operating in your Raspberry Pi. By the top, you’ll have a whole, working software that’s prepared for real-world use.
Studying Aims
- Arrange a FastAPI back-end to combine with the prevailing RAG pipeline and course of queries effectively.
- Design a user-friendly interface utilizing Reflex to work together with the FastAPI back-end and the RAG pipeline.
- Create and check API endpoints for querying and doc ingestion, guaranteeing clean operation with FastAPI.
- Deploy and check the entire software on a Raspberry Pi, guaranteeing each back-end and front-end elements perform seamlessly.
- Perceive the combination between FastAPI and Reflex for a cohesive RAG software expertise.
- Implement and troubleshoot FastAPI and Reflex elements to supply a completely operational RAG software on a Raspberry Pi.
In the event you missed the earlier version, you should definitely test it out right here: Self-Internet hosting RAG Purposes on Edge Units with Langchain and Ollama – Half I.
This text was printed as part of the Knowledge Science Blogathon.
Creating Python Atmosphere
Earlier than we begin with creating the applying we have to setup the surroundings. Create an surroundings and set up the under dependencies:
deeplake
boto3==1.34.144
botocore==1.34.144
fastapi==0.110.3
gunicorn==22.0.0
httpx==0.27.0
huggingface-hub==0.23.4
langchain==0.2.6
langchain-community==0.2.6
langchain-core==0.2.11
langchain-experimental==0.0.62
langchain-text-splitters==0.2.2
langsmith==0.1.83
marshmallow==3.21.3
numpy==1.26.4
pandas==2.2.2
pydantic==2.8.2
pydantic_core==2.20.1
PyMuPDF==1.24.7
PyMuPDFb==1.24.6
python-dotenv==1.0.1
pytz==2024.1
PyYAML==6.0.1
reflex==0.5.6
requests==2.32.3
reflex==0.5.6
reflex-hosting-cli==0.1.13
As soon as the required packages are put in, we have to have the required fashions current within the gadget. We’ll do that utilizing Ollama. Comply with the steps from Half-1 of this text to obtain each the language and embedding fashions. Lastly, create two directories for the back-end and front-end purposes.
As soon as the fashions are pulled utilizing Ollama, we’re able to construct the ultimate software.
Creating the Again-Finish with FastAPI
Within the Half-1 of this text, we’ve constructed the RAG pipeline having each the Ingestion and QnA modules. We’ve got examined each the pipelines utilizing some paperwork and so they have been completely working. Now we have to wrap the pipeline with FastAPI to create consumable API. This can assist us combine it with any front-end software like Streamlit, Chainlit, Gradio, Reflex, React, Angular and so on. Let’s begin by constructing a construction for the applying. Following the construction is totally elective, however be sure that to examine the dependency imports in case you observe a special construction to create the app.
Beneath is the tree construction we are going to observe:
backend
├── app.py
├── necessities.txt
└── src
├── config.py
├── doc_loader
│ ├── base_loader.py
│ ├── __init__.py
│ └── pdf_loader.py
├── ingestion.py
├── __init__.py
└── qna.py
Let’s begin with the config.py. This file will comprise all of the configurable choices for the applying, just like the Ollama URL, LLM title and the embeddings mannequin title. Beneath is an instance:
LANGUAGE_MODEL_NAME = "phi3"
EMBEDDINGS_MODEL_NAME = "nomic-embed-text"
OLLAMA_URL = "http://localhost:11434"
The base_loader.py file comprises the guardian doc loader class that can be inherited by kids doc loader. On this software we’re solely working with PDF recordsdata, so a Baby PDFLoader class can be
created that may inherit the BaseLoader class.
Beneath are the contents of base_loader.py and pdf_loader.py:
# base_loader.py
from abc import ABC, abstractmethod
class BaseLoader(ABC):
def __init__(self, file_path: str) -> None:
self.file_path = file_path
@abstractmethod
async def load_document(self):
go
# pdf_loader.py
import os
from .base_loader import BaseLoader
from langchain.schema import Doc
from langchain.document_loaders.pdf import PyMuPDFLoader
from langchain.text_splitter import CharacterTextSplitter
class PDFLoader(BaseLoader):
def __init__(self, file_path: str) -> None:
tremendous().__init__(file_path)
async def load_document(self):
self.file_name = os.path.basename(self.file_path)
loader = PyMuPDFLoader(file_path=self.file_path)
text_splitter = CharacterTextSplitter(
separator="n",
chunk_size=1000,
chunk_overlap=200,
)
pages = await loader.aload()
total_pages = len(pages)
chunks = []
for idx, web page in enumerate(pages):
chunks.append(
Doc(
page_content=web page.page_content,
metadata=dict(
{
"file_name": self.file_name,
"page_no": str(idx + 1),
"total_pages": str(total_pages),
}
),
)
)
final_chunks = text_splitter.split_documents(chunks)
return final_chunks
We’ve got mentioned the working of pdf_loader within the Half-1 of the article.
Subsequent, let’s construct the Ingestion class. That is identical because the one we constructed within the Half-1 of this text.
Code for Ingestion Class
import os
import config as cfg
from pinecone import Pinecone
from langchain.vectorstores.deeplake import DeepLake
from langchain.embeddings.ollama import OllamaEmbeddings
from .doc_loader import PDFLoader
class Ingestion:
"""Doc Ingestion pipeline."""
def __init__(self):
attempt:
self.embeddings = OllamaEmbeddings(
mannequin=cfg.EMBEDDINGS_MODEL_NAME,
base_url=cfg.OLLAMA_URL,
show_progress=True,
)
self.vector_store = DeepLake(
dataset_path="knowledge/text_vectorstore",
embedding=self.embeddings,
num_workers=4,
verbose=False,
)
besides Exception as e:
elevate RuntimeError(f"Didn't initialize Ingestion system. ERROR: {e}")
async def create_and_add_embeddings(
self,
file: str,
):
attempt:
loader = PDFLoader(
file_path=file,
)
chunks = await loader.load_document()
measurement = await self.vector_store.aadd_documents(paperwork=chunks)
return len(measurement)
besides (ValueError, RuntimeError, KeyError, TypeError) as e:
elevate Exception(f"ERROR: {e}")
Now that we’ve setup the Ingestion class, we’ll go ahead with creating the QnA class. This too is identical because the one we created within the Half-1 of this text.
Code for QnA Class
import os
import config as cfg
from pinecone import Pinecone
from langchain.vectorstores.deeplake import DeepLake
from langchain.embeddings.ollama import OllamaEmbeddings
from langchain_community.llms.ollama import Ollama
from .doc_loader import PDFLoader
class QnA:
"""Doc Ingestion pipeline."""
def __init__(self):
attempt:
self.embeddings = OllamaEmbeddings(
mannequin=cfg.EMBEDDINGS_MODEL_NAME,
base_url=cfg.OLLAMA_URL,
show_progress=True,
)
self.mannequin = Ollama(
mannequin=cfg.LANGUAGE_MODEL_NAME,
base_url=cfg.OLLAMA_URL,
verbose=True,
temperature=0.2,
)
self.vector_store = DeepLake(
dataset_path="knowledge/text_vectorstore",
embedding=self.embeddings,
num_workers=4,
verbose=False,
)
self.retriever = self.vector_store.as_retriever(
search_type="similarity",
search_kwargs={
"ok": 10,
},
)
besides Exception as e:
elevate RuntimeError(f"Didn't initialize Ingestion system. ERROR: {e}")
def create_rag_chain(self):
attempt:
system_prompt = """nnContext: {context}"
"""
immediate = ChatPromptTemplate.from_messages(
[
("system", system_prompt),
("human", "{input}"),
]
)
question_answer_chain = create_stuff_documents_chain(self.mannequin, immediate)
rag_chain = create_retrieval_chain(self.retriever, question_answer_chain)
return rag_chain
besides Exception as e:
elevate RuntimeError(f"Didn't create retrieval chain. ERROR: {e}")
With this we’ve completed creating the code functionalities of the RAG app. Now let’s wrap the app with FastAPI.
Code for the FastAPI Software
import sys
import os
import uvicorn
from src import QnA, Ingestion
from fastapi import FastAPI, Request, File, UploadFile
from fastapi.responses import StreamingResponse
app = FastAPI()
ingestion = Ingestion()
chatbot = QnA()
rag_chain = chatbot.create_rag_chain()
@app.get("https://www.analyticsvidhya.com/")
def hiya():
return {"message": "API Operating in server 8089"}
@app.put up("/question")
async def ask_query(request: Request):
knowledge = await request.json()
query = knowledge.get("query")
async def event_generator():
for chunk in rag_chain.decide("reply").stream({"enter": query}):
yield chunk
return StreamingResponse(event_generator(), media_type="textual content/plain")
@app.put up("/ingest")
async def ingest_document(file: UploadFile = File(...)):
attempt:
os.makedirs("recordsdata", exist_ok=True)
file_location = f"recordsdata/{file.filename}"
with open(file_location, "wb+") as file_object:
file_object.write(file.file.learn())
measurement = await ingestion.create_and_add_embeddings(file=file_location)
return {"message": f"File ingested! Doc rely: {measurement}"}
besides Exception as e:
return {"message": f"An error occured: {e}"}
if __name__ == "__main__":
attempt:
uvicorn.run(app, host="0.0.0.0", port=8089)
besides KeyboardInterrupt as e:
print("App stopped!")
Let’s breakdown the app by every endpoints:
- First we initialize the FastAPI app, the Ingestion and the QnA objects. We then create a RAG chain utilizing the create_rag_chain methodology of QnA class.
- Our first endpoint is a straightforward GET methodology. This can assist us know whether or not the app is wholesome or not. Consider it like a ‘Howdy World’ endpoint.
- The second is the question endpoint. It is a POST methodology and can be used to run the chain. It takes in a request parameter, from which we extract the consumer’s question. Then we create a asynchronous methodology that acts as an asynchronous wrapper across the chain.stream perform name. We have to do that to permit FastAPI to deal with the LLM’s stream perform name, to get a ChatGPT-like expertise within the chat interface. We then wrap the asynchronous methodology with StreamingResponse class and return it.
- The third endpoint is the ingestion endpoint. It is also a POST methodology that takes in your complete file as bytes as enter. We retailer this file within the native listing after which ingest it utilizing the create_and_add_embeddings methodology of Ingestion class.
Lastly, we run the app utilizing uvicorn package deal, utilizing host and port. To check the app, merely run the applying utilizing the next command:
python app.py

Use a API testing IDE like Postman, Insomnia or Bruno for testing the applying. You too can use Thunder Shopper extension to do the identical.
Testing the Ingestion endpoint:

Testing the question endpoint:

Designing the Entrance-Finish with Reflex
We’ve got efficiently created a FastAPI app for the backend of our RAG software. It’s time to construct our front-end. You possibly can selected any front-end library for this, however for this specific article we are going to construct the front-end utilizing Reflex. Reflex is a python-only front-end library, created to construct net purposes, purely utilizing python. It proves us with templates for widespread purposes like calculator, picture era and chatbot. We’ll use the chatbot software template as a begin for our consumer interface. Our closing app may have the next construction, so let’s have it right here for reference.
Frontend Listing
We may have a frontend listing for this:
frontend
├── belongings
│ └── favicon.ico
├── docs
│ └── demo.gif
├── chat
│ ├── elements
│ │ ├── chat.py
│ │ ├── file_upload.py
│ │ ├── __init__.py
│ │ ├── loading_icon.py
│ │ ├── modal.py
│ │ └── navbar.py
│ ├── __init__.py
│ ├── chat.py
│ └── state.py
├── necessities.txt
├── rxconfig.py
└── uploaded_files
Steps for Remaining App
Comply with the steps to organize the grounding for the ultimate app.
Step1: Clone the chat template repository within the frontend listing
git clone https://github.com/reflex-dev/reflex-chat.git .
Step2: Run the next command to initialize the listing as a reflex app
reflex init

This can setup the reflex app and can be able to run and develop.
Step3: Check the app, use the next command from contained in the frontend listing
reflex run

Let’s begin modifying the elements. First let’s modify the chat.py file.
Beneath is the code for a similar:
import reflex as rx
from reflex_demo.elements import loading_icon
from reflex_demo.state import QA, State
message_style = dict(
show="inline-block",
padding="0 10px",
border_radius="8px",
max_width=["30em", "30em", "50em", "50em", "50em", "50em"],
)
def message(qa: QA) -> rx.Element:
"""A single query/reply message.
Args:
qa: The query/reply pair.
Returns:
A part displaying the query/reply pair.
"""
return rx.field(
rx.field(
rx.markdown(
qa.query,
background_color=rx.shade("mauve", 4),
shade=rx.shade("mauve", 12),
**message_style,
),
text_align="proper",
margin_top="1em",
),
rx.field(
rx.markdown(
qa.reply,
background_color=rx.shade("accent", 4),
shade=rx.shade("accent", 12),
**message_style,
),
text_align="left",
padding_top="1em",
),
width="100%",
)
def chat() -> rx.Element:
"""Listing all of the messages in a single dialog."""
return rx.vstack(
rx.field(rx.foreach(State.chats[State.current_chat], message), width="100%"),
py="8",
flex="1",
width="100%",
max_width="50em",
padding_x="4px",
align_self="middle",
overflow="hidden",
padding_bottom="5em",
)
def action_bar() -> rx.Element:
"""The motion bar to ship a brand new message."""
return rx.middle(
rx.vstack(
rx.chakra.type(
rx.chakra.form_control(
rx.hstack(
rx.enter(
rx.enter.slot(
rx.tooltip(
rx.icon("information", measurement=18),
content material="Enter a query to get a response.",
)
),
placeholder="Kind one thing...",
id="query",
width=["15em", "20em", "45em", "50em", "50em", "50em"],
),
rx.button(
rx.cond(
State.processing,
loading_icon(top="1em"),
rx.textual content("Ship", font_family="Ubuntu"),
),
kind="submit",
),
align_items="middle",
),
is_disabled=State.processing,
),
on_submit=State.process_question,
reset_on_submit=True,
),
rx.textual content(
"ReflexGPT could return factually incorrect or deceptive responses. Use discretion.",
text_align="middle",
font_size=".75em",
shade=rx.shade("mauve", 10),
font_family="Ubuntu",
),
rx.brand(margin_top="-1em", margin_bottom="-1em"),
align_items="middle",
),
place="sticky",
backside="0",
left="0",
padding_y="16px",
backdrop_filter="auto",
backdrop_blur="lg",
border_top=f"1px strong {rx.shade('mauve', 3)}",
background_color=rx.shade("mauve", 2),
align_items="stretch",
width="100%",
)
The modifications are minimal from the one current natively within the template.
Subsequent, we are going to edit the chat.py app. That is the primary chat part.
Code for Primary Chat Element
Beneath is the code for it:
import reflex as rx
from reflex_demo.elements import chat, navbar, upload_form
from reflex_demo.state import State
@rx.web page(route="/chat", title="RAG Chatbot")
def chat_interface() -> rx.Element:
return rx.chakra.vstack(
navbar(),
chat.chat(),
chat.action_bar(),
background_color=rx.shade("mauve", 1),
shade=rx.shade("mauve", 12),
min_height="100vh",
align_items="stretch",
spacing="0",
)
@rx.web page(route="https://www.analyticsvidhya.com/", title="RAG Chatbot")
def index() -> rx.Element:
return rx.chakra.vstack(
navbar(),
upload_form(),
background_color=rx.shade("mauve", 1),
shade=rx.shade("mauve", 12),
min_height="100vh",
align_items="stretch",
spacing="0",
)
# Add state and web page to the app.
app = rx.App(
theme=rx.theme(
look="darkish",
accent_color="jade",
),
stylesheets=["https://fonts.googleapis.com/css2?family=Ubuntu&display=swap"],
type={
"font_family": "Ubuntu",
},
)
app.add_page(index)
app.add_page(chat_interface)
That is the code for the chat interface. We’ve got solely added the Font household to the app config, the remainder of the code is identical.
Subsequent let’s edit the state.py file. That is the place the frontend will make name to the API endpoints for response.
Enhancing state.py File
import requests
import reflex as rx
class QA(rx.Base):
query: str
reply: str
DEFAULT_CHATS = {
"Intros": [],
}
class State(rx.State):
chats: dict[str, list[QA]] = DEFAULT_CHATS
current_chat = "Intros"
url: str = "http://localhost:8089/question"
query: str
processing: bool = False
new_chat_name: str = ""
def create_chat(self):
"""Create a brand new chat."""
# Add the brand new chat to the record of chats.
self.current_chat = self.new_chat_name
self.chats[self.new_chat_name] = []
def delete_chat(self):
"""Delete the present chat."""
del self.chats[self.current_chat]
if len(self.chats) == 0:
self.chats = DEFAULT_CHATS
self.current_chat = record(self.chats.keys())[0]
def set_chat(self, chat_name: str):
"""Set the title of the present chat.
Args:
chat_name: The title of the chat.
"""
self.current_chat = chat_name
@rx.var
def chat_titles(self) -> record[str]:
"""Get the record of chat titles.
Returns:
The record of chat names.
"""
return record(self.chats.keys())
async def process_question(self, form_data: dict[str, str]):
# Get the query from the shape
query = form_data["question"]
# Verify if the query is empty
if query == "":
return
mannequin = self.openai_process_question
async for worth in mannequin(query):
yield worth
async def openai_process_question(self, query: str):
"""Get the response from the API.
Args:
form_data: A dict with the present query.
"""
# Add the query to the record of questions.
qa = QA(query=query, reply="")
self.chats[self.current_chat].append(qa)
payload = {"query": query}
# Clear the enter and begin the processing.
self.processing = True
yield
response = requests.put up(self.url, json=payload, stream=True)
# Stream the outcomes, yielding after each phrase.
for answer_text in response.iter_content(chunk_size=512):
# Guarantee answer_text is just not None earlier than concatenation
answer_text = answer_text.decode()
if answer_text is just not None:
self.chats[self.current_chat][-1].reply += answer_text
else:
answer_text = ""
self.chats[self.current_chat][-1].reply += answer_text
self.chats = self.chats
yield
# Toggle the processing flag.
self.processing = False
On this file, we’ve outlined the URL for the question endpoint. We’ve got additionally modified the openai_process_question methodology to ship a POST request to the question endpoint and get the streaming
response, which can be displayed within the chat interface.
Writing Contents of the file_upload.py File
Lastly, let’s write the contents of the file_upload.py file. This part can be displayed at first which is able to enable us to add the file for ingestion.
import reflex as rx
import os
import time
import requests
class UploadExample(rx.State):
importing: bool = False
ingesting: bool = False
progress: int = 0
total_bytes: int = 0
ingestion_url = "http://127.0.0.1:8089/ingest"
async def handle_upload(self, recordsdata: record[rx.UploadFile]):
self.ingesting = True
yield
for file in recordsdata:
file_bytes = await file.learn()
file_name = file.filename
recordsdata = {
"file": (os.path.basename(file_name), file_bytes, "multipart/form-data")
}
response = requests.put up(self.ingestion_url, recordsdata=recordsdata)
self.ingesting = False
yield
if response.status_code == 200:
# yield rx.redirect("/chat")
self.show_redirect_popup()
def handle_upload_progress(self, progress: dict):
self.importing = True
self.progress = spherical(progress["progress"] * 100)
if self.progress >= 100:
self.importing = False
def cancel_upload(self):
self.importing = False
return rx.cancel_upload("upload3")
def upload_form():
return rx.vstack(
rx.add(
rx.flex(
rx.textual content(
"Drag and drop file right here or click on to pick out file",
font_family="Ubuntu",
),
rx.icon("add", measurement=30),
course="column",
align="middle",
),
id="upload3",
border="1px strong rgb(233, 233,233, 0.4)",
margin="5em 0 10px 0",
background_color="rgb(107,99,246)",
border_radius="8px",
padding="1em",
),
rx.vstack(rx.foreach(rx.selected_files("upload3"), rx.textual content)),
rx.cond(
~UploadExample.ingesting,
rx.button(
"Add",
on_click=UploadExample.handle_upload(
rx.upload_files(
upload_id="upload3",
on_upload_progress=UploadExample.handle_upload_progress,
),
),
),
rx.flex(
rx.spinner(measurement="3", loading=UploadExample.ingesting),
rx.button(
"Cancel",
on_click=UploadExample.cancel_upload,
),
align="middle",
spacing="3",
),
),
rx.alert_dialog.root(
rx.alert_dialog.set off(
rx.button("Proceed to Chat", color_scheme="inexperienced"),
),
rx.alert_dialog.content material(
rx.alert_dialog.title("Redirect to Chat Interface?"),
rx.alert_dialog.description(
"You'll be redirected to the Chat Interface.",
measurement="2",
),
rx.flex(
rx.alert_dialog.cancel(
rx.button(
"Cancel",
variant="gentle",
color_scheme="grey",
),
),
rx.alert_dialog.motion(
rx.button(
"Proceed",
color_scheme="inexperienced",
variant="strong",
on_click=rx.redirect("/chat"),
),
),
spacing="3",
margin_top="16px",
justify="finish",
),
type={"max_width": 450},
),
),
align="middle",
)
This part will enable us to add a file and ingest it into the vector retailer. It makes use of the ingest endpoint of our FastAPI app to add and ingest the file. After ingestion, the consumer can merely transfer
to the chat interface for asking queries.
With this we’ve accomplished constructing the front-end for our software. Now we might want to check the applying utilizing some doc.
Testing and Deployment
Now let’s check the applying on some manuals or paperwork. To make use of the applying, we have to run each the back-end app and the reflex app individually. Run the back-end app from it’s listing utilizing the
following command:
python app.py
Anticipate the FastAPI to start out operating. Then in one other terminal occasion run the front-end app utilizing the next command:
reflex run
One the apps are up and operating, bought to the following URL to entry the reflex app. Initially we might be within the File Add web page. Add a file and press the add button.

The file can be uploaded and ingested. This can take some time relying on the doc measurement and
the gadget specs. As soon as it’s carried out, click on on the ‘Proceed to Chat’ button to maneuver to the chat interface. Write your question and press Ship.
Conclusion
On this two half collection, you’ve now constructed a whole and useful RAG software on a Raspberry Pi, from creating the core pipeline to wrapping it with a FastAPI back-end and growing a Reflex-based front-end. With these instruments, your RAG pipeline is accessible and interactive, offering real-time question processing by a user-friendly net interface. By mastering these steps, you’ve gained invaluable expertise in constructing and deploying end-to-end purposes on a compact, environment friendly platform. This setup opens the door to numerous prospects for deploying AI-driven purposes on resource-constrained units just like the Raspberry Pi, making cutting-edge know-how extra accessible and sensible for on a regular basis use.
Key Takeaways
- An in depth information is supplied on organising the event surroundings, together with putting in obligatory dependencies and fashions utilizing Ollama, guaranteeing the applying is prepared for the ultimate construct.
- The article explains the right way to wrap the RAG pipeline in a FastAPI software, together with organising endpoints for querying the mannequin and ingesting paperwork, making the pipeline accessible through an online API.
- The front-end of the RAG software is constructed utilizing Reflex, a Python-only front-end library. The article demonstrates the right way to modify the chat software template to create a user-friendly interface for interacting with the RAG pipeline.
- The article guides on integrating the FastAPI backend with the Reflex front-end and deploying the entire software on a Raspberry Pi, guaranteeing seamless operation and consumer accessibility.
- Sensible steps are supplied for testing each the ingestion and question endpoints utilizing instruments like Postman or Thunder Shopper, together with operating and testing the Reflex front-end to make sure your complete software capabilities as anticipated.
Steadily Requested Query
A. There’s a platform named Tailscale that enables your units to be related to a personal safe community, accessible solely to you. You possibly can add your Raspberry Pi and different units to Tailscale units and hook up with the VPN to entry your apps, from anyplace throughout the world.
A. That’s the constraint as a consequence of low {hardware} specs of Raspberry Pi. The article is only a head up tutorial on the right way to begin constructing RAG app utilizing Raspberry Pi and Ollama.
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