main.py

import os
import glob
import shutil
import subprocess
import asyncio


from typing import Any, Dict, List

from fastapi import FastAPI, HTTPException, UploadFile, WebSocket, WebSocketDisconnect
from fastapi.staticfiles import StaticFiles

from pydantic import BaseModel

# import torch
from langchain.chains import RetrievalQA
from langchain.embeddings import HuggingFaceInstructEmbeddings
from langchain.prompts import PromptTemplate
from langchain.memory import ConversationBufferMemory
from langchain.callbacks.base import BaseCallbackHandler
from langchain.schema import LLMResult

# from langchain.embeddings import HuggingFaceEmbeddings
from load_models import load_model

# from langchain.callbacks.streaming_stdout import StreamingStdOutCallbackHandler
from langchain.vectorstores import Chroma

from constants import CHROMA_SETTINGS, EMBEDDING_MODEL_NAME, PERSIST_DIRECTORY, MODEL_ID, MODEL_BASENAME, PATH_NAME_SOURCE_DIRECTORY

class Predict(BaseModel):
    prompt: str

class Delete(BaseModel):
    filename: str

# if torch.backends.mps.is_available():
#     DEVICE_TYPE = "mps"
# elif torch.cuda.is_available():
#     DEVICE_TYPE = "cuda"
# else:
#     DEVICE_TYPE = "cpu"

DEVICE_TYPE = "cuda"
SHOW_SOURCES = True

EMBEDDINGS = HuggingFaceInstructEmbeddings(model_name=EMBEDDING_MODEL_NAME, model_kwargs={"device": DEVICE_TYPE})

# load the vectorstore
DB = Chroma(
    persist_directory=PERSIST_DIRECTORY,
    embedding_function=EMBEDDINGS,
    client_settings=CHROMA_SETTINGS,
)

RETRIEVER = DB.as_retriever()

class MyCustomSyncHandler(BaseCallbackHandler):
    def __init__(self):
        self.end = False
        self.callback = None

    def on_llm_start(
        self, serialized: Dict[str, Any], prompts: List[str], **kwargs: Any
    ) -> None:
        self.end = False
        self.callback = None

    def on_llm_end(self, response: LLMResult, **kwargs: Any) -> None:
        self.end = True

    def on_llm_new_token(self, token: str, **kwargs) -> Any:
        if self.callback :
            self.callback(token)

        print(token)

# Create State
handlerToken = MyCustomSyncHandler()

LLM = load_model(device_type=DEVICE_TYPE, model_id=MODEL_ID, model_basename=MODEL_BASENAME, stream=True, callbacks=[handlerToken])

template = """You are a helpful, respectful and honest assistant.
Always answer in the most helpful and safe way possible without trying to make up an answer, if you don't know the answer just say "I don't know" and don't share false information or topics that were not provided in your training. Use a maximum of 15 sentences. Your answer should be as concise and clear as possible. Always say "thank you for asking!" at the end of your answer.
Context: {context}
Question: {question}
"""

memory = ConversationBufferMemory(input_key="question", memory_key="history")

QA_CHAIN_PROMPT = PromptTemplate(input_variables=["context", "question"], template=template)

QA = RetrievalQA.from_chain_type(
    llm=LLM,
    chain_type="stuff",
    retriever=RETRIEVER,
    return_source_documents=SHOW_SOURCES,
    chain_type_kwargs={
        "prompt": QA_CHAIN_PROMPT,
    },
)

app = FastAPI(title="homepage-app")
api_app = FastAPI(title="api app")

app.mount("/api", api_app, name="api")
app.mount("/", StaticFiles(directory="static",html = True), name="static")

@api_app.get("/training")
def run_ingest_route():
    global DB
    global RETRIEVER
    global QA

    try:
        if os.path.exists(PERSIST_DIRECTORY):
            try:
                shutil.rmtree(PERSIST_DIRECTORY)
            except OSError as e:
                raise HTTPException(status_code=500, detail=f"Error: {e.filename} - {e.strerror}.")
        else:
            raise HTTPException(status_code=500, detail="The directory does not exist")

        run_langest_commands = ["python", "ingest.py"]

        if DEVICE_TYPE == "cpu":
            run_langest_commands.append("--device_type")
            run_langest_commands.append(DEVICE_TYPE)

        result = subprocess.run(run_langest_commands, capture_output=True)

        if result.returncode != 0:
            raise HTTPException(status_code=400, detail="Script execution failed: {}")

        # load the vectorstore
        DB = Chroma(
            persist_directory=PERSIST_DIRECTORY,
            embedding_function=EMBEDDINGS,
            client_settings=CHROMA_SETTINGS,
        )

        RETRIEVER = DB.as_retriever()

        QA = RetrievalQA.from_chain_type(
            llm=LLM,
            chain_type="stuff",
            retriever=RETRIEVER,
            return_source_documents=SHOW_SOURCES,
            chain_type_kwargs={
                "prompt": QA_CHAIN_PROMPT,
                "memory": memory
            },
        )


        return {"response": "The training was successfully completed"}
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Error occurred: {str(e)}")

@api_app.get("/api/files")
def get_files():
    upload_dir = os.path.join(os.getcwd(), PATH_NAME_SOURCE_DIRECTORY)
    files = glob.glob(os.path.join(upload_dir, '*'))

    return {"directory": upload_dir, "files": files}

@api_app.delete("/api/delete_document")
def delete_source_route(data: Delete):
    filename = data.filename
    path_source_documents = os.path.join(os.getcwd(), PATH_NAME_SOURCE_DIRECTORY)
    file_to_delete = f"{path_source_documents}/{filename}"

    if os.path.exists(file_to_delete):
        try:
            os.remove(file_to_delete)
            print(f"{file_to_delete} has been deleted.")

            return {"message": f"{file_to_delete} has been deleted."}
        except OSError as e:
            raise HTTPException(status_code=400, detail=print(f"error: {e}."))
    else:
         raise HTTPException(status_code=400, detail=print(f"The file {file_to_delete} does not exist."))

@api_app.post('/predict')
async def predict(data: Predict):
    global QA
    user_prompt = data.prompt
    if user_prompt:
        res = QA(user_prompt)

        answer, docs = res["result"], res["source_documents"]

        prompt_response_dict = {
            "Prompt": user_prompt,
            "Answer": answer,
        }

        prompt_response_dict["Sources"] = []
        for document in docs:
            prompt_response_dict["Sources"].append(
                (os.path.basename(str(document.metadata["source"])), str(document.page_content))
            )

        return {"response": prompt_response_dict}
    else:
        raise HTTPException(status_code=400, detail="Prompt Incorrect")

@api_app.post("/save_document/")
async def create_upload_file(file: UploadFile):
    # Get the file size (in bytes)
    file.file.seek(0, 2)
    file_size = file.file.tell()

    # move the cursor back to the beginning
    await file.seek(0)

    if file_size > 10 * 1024 * 1024:
        # more than 10 MB
        raise HTTPException(status_code=400, detail="File too large")

    content_type = file.content_type

    if content_type not in [
        "text/plain",
        "text/markdown",
        "text/x-markdown",
        "text/csv",
        "application/msword",
        "application/pdf",
        "application/vnd.ms-excel",
        "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
        "text/x-python",
        "application/x-python-code"]:
        raise HTTPException(status_code=400, detail="Invalid file type")

    upload_dir = os.path.join(os.getcwd(), PATH_NAME_SOURCE_DIRECTORY)
    if not os.path.exists(upload_dir):
        os.makedirs(upload_dir)

    dest = os.path.join(upload_dir, file.filename)

    with open(dest, "wb") as buffer:
        shutil.copyfileobj(file.file, buffer)

    return {"filename": file.filename}

@api_app.websocket("/ws/{client_id}")
async def websocket_endpoint(websocket: WebSocket,  client_id: int):
    global QA

    await websocket.accept()

    oldReceiveText = ''

    try:
        while True:
            prompt = await websocket.receive_text()

            if (oldReceiveText != prompt):
                handlerToken.callback = websocket.send_text
                oldReceiveText = prompt
                await QA(prompt)

    except WebSocketDisconnect:
        print('disconnect')
    except RuntimeError as error:
        print(error)