How to manage multiple versions of the same library in one project?

Question

How can I run two functions within the same FastAPI application where one function requires transformers==4.32.8 and the other requires transformers==5.32.8 ?

Naimish Makwana · Answer

Running two different versions of the same library within a single FastAPI application can be tricky due to dependency conflicts. However you can achieve this by using separate virtual environments and subprocesses. Here’s a step-by-step guide: Create Virtual Environments : Set up two separate virtual environments each with the required version of the transformers library. Install Dependencies : # For transformers==4.32.8 python -m venv env1 source env1/bin/activate pip install transformers==4.32.8 deactivate # For transformers==5.32.8 python -m venv env2 source env2/bin/activate pip install transformers==5.32.8 deactivate Create Python Scripts : Write separate Python scripts for each function that uses the respective version of the transformers library. # script1.py (uses transformers==4.32.8) import transformers def function1(): # Your code here return Result from transformers 4.32.8 # script2.py (uses transformers==5.32.8) import transformers def function2(): # Your code here return Result from transformers 5.32.8 Use Subprocesses in FastAPI : In your FastAPI application use the subprocess module to call these scripts. from fastapi import FastAPI import subprocess app = FastAPI() @app.get(/function1) def run_function1(): result = subprocess.run([env1/bin/python script1.py] capture_output=True text=True) return {result: result.stdout} @app.get(/function2) def run_function2(): result = subprocess.run([env2/bin/python script2.py] capture_output=True text=True) return {result: result.stdout} Run the FastAPI Application : uvicorn main:app --reload This setup allows you to run each function in its own isolated environment avoiding dependency conflicts. Let me know if you need further assistance!