99 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			99 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| """passbook policy engine"""
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| from multiprocessing import Pipe
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| from multiprocessing.connection import Connection
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| from typing import List, Optional, Tuple
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| 
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| from django.core.cache import cache
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| from django.http import HttpRequest
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| from structlog import get_logger
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| 
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| from passbook.core.models import Policy, User
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| from passbook.policies.process import PolicyProcess, cache_key
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| from passbook.policies.struct import PolicyRequest, PolicyResult
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| 
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| LOGGER = get_logger()
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| 
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| 
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| class PolicyProcessInfo:
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|     """Dataclass to hold all information and communication channels to a process"""
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| 
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|     process: PolicyProcess
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|     connection: Connection
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|     result: Optional[PolicyResult]
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|     policy: Policy
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| 
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|     def __init__(self, process: PolicyProcess, connection: Connection, policy: Policy):
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|         self.process = process
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|         self.connection = connection
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|         self.policy = policy
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|         self.result = None
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| 
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| 
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| class PolicyEngine:
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|     """Orchestrate policy checking, launch tasks and return result"""
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| 
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|     use_cache: bool = True
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|     policies: List[Policy] = []
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|     request: PolicyRequest
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| 
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|     __processes: List[PolicyProcessInfo] = []
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| 
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|     def __init__(self, policies, user: User, request: HttpRequest = None):
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|         self.policies = policies
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|         self.request = PolicyRequest(user)
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|         if request:
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|             self.request.http_request = request
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|         self.__processes = []
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| 
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|     def _select_subclasses(self) -> List[Policy]:
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|         """Make sure all Policies are their respective classes"""
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|         return (
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|             Policy.objects.filter(pk__in=[x.pk for x in self.policies])
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|             .select_subclasses()
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|             .order_by("order")
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|         )
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| 
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|     def build(self) -> "PolicyEngine":
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|         """Build task group"""
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|         cached_policies = []
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|         for policy in self._select_subclasses():
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|             cached_policy = cache.get(cache_key(policy, self.request.user), None)
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|             if cached_policy and self.use_cache:
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|                 LOGGER.debug("Taking result from cache", policy=policy)
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|                 cached_policies.append(cached_policy)
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|             else:
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|                 LOGGER.debug("Evaluating policy", policy=policy)
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|                 our_end, task_end = Pipe(False)
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|                 task = PolicyProcess(policy, self.request, task_end)
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|                 LOGGER.debug("Starting Process", policy=policy)
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|                 task.start()
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|                 self.__processes.append(
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|                     PolicyProcessInfo(process=task, connection=our_end, policy=policy)
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|                 )
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|         # If all policies are cached, we have an empty list here.
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|         for proc_info in self.__processes:
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|             proc_info.process.join(proc_info.policy.timeout)
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|             # Only call .recv() if no result is saved, otherwise we just deadlock here
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|             if not proc_info.result:
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|                 proc_info.result = proc_info.connection.recv()
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|         return self
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| 
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|     @property
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|     def result(self) -> Tuple[bool, List[str]]:
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|         """Get policy-checking result"""
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|         messages: List[str] = []
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|         for proc_info in self.__processes:
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|             LOGGER.debug(
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|                 "Result", policy=proc_info.policy, passing=proc_info.result.passing
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|             )
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|             if proc_info.result.messages:
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|                 messages += proc_info.result.messages
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|             if not proc_info.result.passing:
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|                 return False, messages
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|         return True, messages
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| 
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|     @property
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|     def passing(self) -> bool:
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|         """Only get true/false if user passes"""
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|         return self.result[0]
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