Locust: See what request generated a failure

[gkristjansson]

It would be very to nice to able to see what http request generated a failure. It also would be useful to include the payload that was sent with the request.

[Jahaja]

Indeed, this has been on the todo list for a while. If time allows, I'll see if I can get this sorted once and for all.

[heyman]

I agree. We just have to make sure to use sampling of data, so that we don't end up using up all bandwidth when running Locust distributed with a lot of slaves.

[gkristjansson]

About the number of samples, one of the issues that I have found is that the app I am load testing uses lot of unique urls, which makes the web interface heavy to load, or even impossible

[Jahaja]

You can name your requests using the name parameter to .get(), .post() etc.

l.get("/profile/%d" % user_id, name="/profile/[user-id]")

[Alerion]

You can use Event hooks, like:

from locust.events import request_failure

def on_failure(request_type, name, response_time, exception, **kwargs):
    print exception.request.url
    print exception.response.status_code
    print exception.response.content

request_failure += on_failure

[ghost]

The above is an excellent debugging tip.

[BenjamenMeyer]

perhaps something like https://github.com/BenjamenMeyer/locust/tree/enhancement_track_responses would be good? It's more specific to an API that I'm developing, but it could probably be generalized by making the 'transaction-id' header field name a configuration variable.

[cyberw]

If it isnt already in there, we should add @Alerion ’s suggestion to the documentation. Closing this.

[rokcarl]

Now in master it doesn't work, probably the API is changed and the API docs are not yet up-to-date. I get:

TypeError: unsupported operand type(s) for +=: 'EventHook' and 'function'

[heyman]

The docs are up to date here: https://docs.locust.io/en/latest/api.html#event-hooks
(you linked to the latest stable docs).

[rokcarl]

Ah, my bad, thank you!

[Anu35]

Hi All

I got "TypeError: unsupported operand type(s) for +=: 'EventHook' and 'function'" I solved it by adding locust.events to requests.

Then now I am getting new error
Traceback (most recent call last):
File "C:UsersxxxxxxAppDataLocalProgramsPythonPython38Librunpy.py", line 193, in _run_module_as_main
return _run_code(code, main_globals, None,
File "C:UsersxxxxxxAppDataLocalProgramsPythonPython38Librunpy.py", line 86, in _run_code
exec(code, run_globals)
File "C:UsersxxxxxxxxxxxvenvScriptslocust.exe__main__.py", line 7, in
File "c:usersxxxxxxxxxxxvenvlibsite-packageslocustmain.py",
line 133, in main
options = parse_options()
File "c:usersxxxxxxxxxvenvlibsite-packageslocustargument_parser.py", line 442, in parse_options
parser = get_parser()
File "c:usersxxxxxxxxxxxvenvlibsite-packageslocustargument_parser.py", line 437, in get_parser
locust.events.init_command_line_parser.fire(parser=parser)
AttributeError: module 'locust.events' has no attribute 'init_command_line_parser'

I am using all latest version python --3.8
PIP -20.0.2
Locust --1.2.3

Can you please help fix this error what eactly is reason for this error and what package needs to be updated.

[ajorgeg21]

I have the same error, how can I solve it?