promo_v4.py

import pandas as pd
import requests

error_list = []

df = pd.read_csv('promos.csv')

for i, row in df.iterrows():
    
    if i % 100 == 0:
        print(f'Working on row {i}')
    
    user_id = row['user_id']
    
    url = f'http://internal.services.com/promotions?user_id={user_id}'
    r = requests.post(url)
    
    if r.status_code != 200:
        error_list.append(user_id)
        
error_df = pd.DataFrame(error_list, columns=['user_id'])
error_df.to_csv('error_user_ids.csv', index=False)