Plugin Debugging¶
Debugging plugins can sometimes be complicated since there are so many classes, which are tied together in an implicit way. I have collected some frequent questions about debugging.
An uncaught exception makes the plugin return UNKNOWN. Where is the cause?¶
When your plugin raises an exception, you may get very little output. Example:
$ check_users.py
USERS UNKNOWN: RuntimeError: error
Set the verbose parameter of main()
to some value greater than zero and you will get the full traceback:
$ check_users.py -v
USERS UNKNOWN: RuntimeError: error
Traceback (most recent call last):
File "src/nagiosplugin/runtime.py", line 38, in wrapper
return func(*args, **kwds)
File "src/nagiosplugin/examples/check_users.py", line 104, in main
check.main(args.verbose, args.timeout)
File "src/nagiosplugin/check.py", line 110, in main
runtime.execute(self, verbose, timeout)
File "src/nagiosplugin/runtime.py", line 118, in execute
with_timeout(self.timeout, self.run, check)
File "src/nagiosplugin/platform/posix.py", line 19, in with_timeout
func(*args, **kwargs)
File "src/nagiosplugin/runtime.py", line 107, in run
check()
File "src/nagiosplugin/check.py", line 95, in __call__
self._evaluate_resource(resource)
File "src/nagiosplugin/check.py", line 73, in _evaluate_resource
metrics = resource.probe()
File "src/nagiosplugin/examples/check_users.py", line 57, in probe
self.users = self.list_users()
File "src/nagiosplugin/examples/check_users.py", line 34, in list_users
raise RuntimeError('error')
RuntimeError: error
A Check constructor dies with “cannot add type <...>”¶
When you see the following exception raised from
Check() (or Check.add()):
UNKNOWN: TypeError: ("cannot add type <class '__main__.Users'> to check", <__main__.Users object at 0x7f0c64f73f90>)
chances are high that you are trying to add an object that is not an instance
from Resource, Context, Summary, or Results or its subclasses. A common
error is to base a resource class on object instead of
Resource.