Simple Python script to invoke ChatGPT API.

chat.py

#!/usr/bin/env python3
#
# Takes a chat transcript (for ChatGPT) on stdin, calls the OpenAI
# ChatGPT API, and prints the response on stdout.
#
# Your OpenAI API key must be set in the environment variable
# OPENAI_API_KEY.
#
# Logs are written to ~/chat.log.

import sys
import os
import re
import openai
import datetime
import logging

# All input/output to the API is logged here.
# Expand filename to full path.
LOG_FILE = os.path.expanduser('~/chat.log')

# Read stdin and save into a string.
def read_stdin():
    return sys.stdin.read()

def set_openai_key():
  # Read key from env var OPENAI_API_KEY.
  openai.api_key = os.getenv("OPENAI_API_KEY")

def parse_input(input):
  logging.debug(input)
  # Split input into lines and iterate over them.
  s = ''
  cur_role = ''
  messages = []
  for line in input.splitlines():
    # Check if line matches a regex like '%user%.
    r = re.match(r"^%(.+)%", line)
    if r:
      messages.append({"role": cur_role, "content": s})
      s = ''
      cur_role = r.group(1)
    else:
      s += line
  messages.append({"role": cur_role, "content": s})
  return messages[1:]
  
def get_response(messages):
  completion = openai.ChatCompletion.create(
    model="gpt-3.5-turbo",
    messages=messages,
  )
  logging.debug(completion)
  reply = completion["choices"][0]["message"]["content"]
  role = completion["choices"][0]["message"]["role"]
  logging.debug('==== OUTPUT⇟\n')
  logging.debug(reply)
  logging.debug(role)
  return reply

def main():
  # Send logging messages to a file.
  logging.basicConfig(filename=LOG_FILE, level=logging.DEBUG)

  # Get date and time in standard format.
  logging.debug(str(datetime.datetime.now()))

  messages = parse_input(read_stdin())
  logging.debug('==== INPUT⇟\n')
  logging.debug(messages)
  set_openai_key()
  reply = get_response(messages)
  print(reply)
  
if __name__ == '__main__':
    main()