Stop user exception arguments aren’t logged

[ddennerline3]

The StopUser exception can be useful for raising when a user cannot authenticate - especially in the on_start() method. Right now the StopUser exception is not logged, so it’s difficult to determine why users are stopping.

@final
def run(self):
...
   try:
       # run the TaskSet on_start method, if it has one
       try:
           self.on_start()
       except Exception as e:
...
       self._taskset_instance.run()
   except (GreenletExit, StopUser) as e:
       # run the on_stop method, if it has one
+      if e.args:
+          logger.warning(str(e))
       self.on_stop()

Example code:

names = ["bill", "joe", "jane", "jill", "jack", "john", "jim", "jake", "josh", "james"]
names_index = 0

def post_login(user_name: str) -> tuple[bool, str]:
    if user_name == "jake":
        return False, "Your account has been locked"
    return True, ""

class QuickstartUser(FastHttpUser):
    wait_time = between(1, 2)

    def on_start(self):
        global names_index

        n = names[names_index]
        logger.info("User is starting: %s", n)
        names_index += 1
        if names_index >= len(names):
            names_index = 0
        result = post_login(n)
        if not result[0]:
            raise StopUser(f"Cannot login: name={n}, error={result[1]}")

[cyberw]

Users raising a StopUser exception is completely normal, so I don't think we can/should log it. If it is an actual error, maybe log something manually? Something like

import logging
logger = logging.getLogger(__name__)
...
           if not result[0]:
               logger.info(f"Cannot login: name={n}, error={result[1]}")
               raise StopUser()

[ddennerline3]

We currently have log statements at every raised (as you suggested) location. I am suggesting that if there's a message value, then log that message in one location instead of having a log statement at every location (duplicate code).