from prometheus_client import start_http_server, Summary
 import random
 import time

 # Create a metric to track time spent and requests made.
 REQUEST_TIME = Summary('request_processing_seconds', 'Time spent processing request')

 # Decorate function with metric.
 @REQUEST_TIME.time()
 def process_request(t):
     """A dummy function that takes some time."""
     time.sleep(t)

 if __name__ == '__main__':
     # Start up the server to expose the metrics.
     start_http_server(8000)
     # Generate some requests.
     while True:
         process_request(random.random())