Stop vassal spawning if a certain condition is not fufilled

nairajin123

Hi All,
I am using uWSGI emperor mode and spawning vassals dynamically and wanted to check a condition before a vassal is spawned.
I tried different hooks, the pre-app hook and vassals-start-hook primarily.
pre-app: hook is fatal and when returned non-zero terminates the whole instance including the emperor.
vassals-start-hook : Runs at the start of each vassal but doesn't stop the vassal from spawning.

Any advice/suggestions on how to check certain condition before spawning a dynamic vassal.

sean

nairajin123 According to the uWSGI docs hook-as-emperor-before-vassal sounds like what you need:

"run the specified hook before the new vassal is spawned"

nairajin123

Thanks appreciate that. But not sure what I am missing here , I upgraded to latest uwsgi stable version uwsgi-2.0.22 but i can't find hook-as-emperor-before-vassal option.
When i run --help I don't find it also when I add it to my emperor config file I get
[strict-mode] unknown config directive: hook-as-emperor-before-vassal
Documentation says its part of core.
I built uwsgi using:
python uwsgiconfig.py --build
Any advice.

sean

nairajin123 hmm that's weird, github shows the option was added 9 years ago but you're right - it doesn't appear in in the help options.

I do see the following:

  --hook-as-vassal                        run the specified hook before exec()ing the vassal

Maybe that's what you need?