Coverage for /pythoncovmergedfiles/medio/medio/src/airflow/build/lib/airflow/triggers/base.py: 55%

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16# under the License. 

17from __future__ import annotations 

18 

19import abc 

20from typing import Any, AsyncIterator 

21 

22from airflow.utils.log.logging_mixin import LoggingMixin 

23 

24 

25class BaseTrigger(abc.ABC, LoggingMixin): 

26 """ 

27 Base class for all triggers. 

28 

29 A trigger has two contexts it can exist in: 

30 

31 - Inside an Operator, when it's passed to TaskDeferred 

32 - Actively running in a trigger worker 

33 

34 We use the same class for both situations, and rely on all Trigger classes 

35 to be able to return the arguments (possible to encode with Airflow-JSON) that will 

36 let them be re-instantiated elsewhere. 

37 """ 

38 

39 def __init__(self, **kwargs): 

40 

41 # these values are set by triggerer when preparing to run the instance 

42 # when run, they are injected into logger record. 

43 self.task_instance = None 

44 self.trigger_id = None 

45 

46 def _set_context(self, context): 

47 """ 

48 This method, part of LoggingMixin, is used mainly for configuration of logging 

49 for tasks, but is not used for triggers. 

50 """ 

51 raise NotImplementedError 

52 

53 @abc.abstractmethod 

54 def serialize(self) -> tuple[str, dict[str, Any]]: 

55 """ 

56 Returns the information needed to reconstruct this Trigger. 

57 

58 :return: Tuple of (class path, keyword arguments needed to re-instantiate). 

59 """ 

60 raise NotImplementedError("Triggers must implement serialize()") 

61 

62 @abc.abstractmethod 

63 async def run(self) -> AsyncIterator[TriggerEvent]: 

64 """ 

65 Runs the trigger in an asynchronous context. 

66 

67 The trigger should yield an Event whenever it wants to fire off 

68 an event, and return None if it is finished. Single-event triggers 

69 should thus yield and then immediately return. 

70 

71 If it yields, it is likely that it will be resumed very quickly, 

72 but it may not be (e.g. if the workload is being moved to another 

73 triggerer process, or a multi-event trigger was being used for a 

74 single-event task defer). 

75 

76 In either case, Trigger classes should assume they will be persisted, 

77 and then rely on cleanup() being called when they are no longer needed. 

78 """ 

79 raise NotImplementedError("Triggers must implement run()") 

80 yield # To convince Mypy this is an async iterator. 

81 

82 async def cleanup(self) -> None: 

83 """ 

84 Cleanup the trigger. 

85 

86 Called when the trigger is no longer needed, and it's being removed 

87 from the active triggerer process. 

88 

89 This method follows the async/await pattern to allow to run the cleanup 

90 in triggerer main event loop. Exceptions raised by the cleanup method 

91 are ignored, so if you would like to be able to debug them and be notified 

92 that cleanup method failed, you should wrap your code with try/except block 

93 and handle it appropriately (in async-compatible way). 

94 """ 

95 

96 def __repr__(self) -> str: 

97 classpath, kwargs = self.serialize() 

98 kwargs_str = ", ".join(f"{k}={v}" for k, v in kwargs.items()) 

99 return f"<{classpath} {kwargs_str}>" 

100 

101 

102class TriggerEvent: 

103 """ 

104 Something that a trigger can fire when its conditions are met. 

105 

106 Events must have a uniquely identifying value that would be the same 

107 wherever the trigger is run; this is to ensure that if the same trigger 

108 is being run in two locations (for HA reasons) that we can deduplicate its 

109 events. 

110 """ 

111 

112 def __init__(self, payload: Any): 

113 self.payload = payload 

114 

115 def __repr__(self) -> str: 

116 return f"TriggerEvent<{self.payload!r}>" 

117 

118 def __eq__(self, other): 

119 if isinstance(other, TriggerEvent): 

120 return other.payload == self.payload 

121 return False