[WIP] Initial version

checklib.py

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+import sys
+import traceback
+import argparse
+from enums import Enum
+
+"""
+CheckLib: a simple wrapper around Icinga checks dealing with common
+code like correct error codes and output formatting
+
+The main class is `Check`, other classes are just helpers.
+"""
+
+class Result(Enum):
+	"""
+	Enumeration of possible check results.
+
+	The values are related return codes.
+	"""
+	OK = 0
+	WARNING = 1
+	CRITICAL = 2
+	UNKNOWN = 3
+
+class Check:
+	"""
+	The class representing the check.
+
+	Expected usage is by invoking the `run` classmethod, which overtakes
+	the control, performs the check and returns the correct return
+	value.
+
+	The sequence is following:
+		1. run: Runs the check:
+			1. __init__: initialization
+				- Creation of default values in the instance
+				- Preparation of argument parser (TODO: Do we want this here?)
+			1. prepare_argparse: Optionally tweaks argparse's
+			   ArgumentParser, e.g. adding more parameters
+			1. self.args = argparse.parse_args(sys.argv)
+			1. check(): the function to check state and populate
+			   self.result, self.short_message and so on.
+			1. sys.exit with the relevant exit code according to
+			   self.result
+			- If anything fails, e.g. by raising an exception,
+			the run method returns the UNKNOWN result and
+			uses the traceback as message.
+	
+	Instead of using self.check, the default implementation invokes
+	measure method and compares its value to thresholds given either
+	by semi-standard arguments, or defaults defined in the class.
+	(If neither method is defined, the check fails. In other words,
+	you need to either implement measure, or override check.)
+
+	FIXME: It is currently not documented, which attributes of the instance
+	are used.
+	"""
+
+	@classmethod
+	def run(cls, *args, **kwargs):
+		"""
+		This method implements the checking start-to-end.
+
+		The arguments, if any, are passed to the __init__ of the class.
+		"""
+
+		try:
+			

example.py

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+from checklib import Check, Result
+
+class MyCheck(Check):
+	def check(self):
+		self.result.state = Result.UNKNOWN
+		self.result.short_message = 'I don\'t know :-)'
+	
+	def add_arguments(self):
+		pass
+
+	# Collect argparse arguments at self.arguments
+
+	# If defining __init__, call super().__init__ first -- it populates
+	# self.result, self.argumentparser and so on.