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prefect.cache_policies

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Classes

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CachePolicy

Base class for all cache policies.

Methods:

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from_cache_key_fn

from_cache_key_fn(cls, cache_key_fn: Callable[['TaskRunContext', Dict[str, Any]], Optional[str]]) -> 'CacheKeyFnPolicy'

Given a function generates a key policy.

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configure

configure(self, key_storage: Union['WritableFileSystem', str, Path, None] = None, lock_manager: Optional['LockManager'] = None, isolation_level: Union[Literal['READ_COMMITTED', 'SERIALIZABLE'], 'IsolationLevel', None] = None) -> Self

Configure the cache policy with the given key storage, lock manager, and isolation level.

Args:

  • key_storage: The storage to use for cache keys. If not provided, the current key storage will be used.
  • lock_manager: The lock manager to use for the cache policy. If not provided, the current lock manager will be used.
  • isolation_level: The isolation level to use for the cache policy. If not provided, the current isolation level will be used.

Returns:

  • A new cache policy with the given key storage, lock manager, and isolation level.

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compute_key

compute_key(self, task_ctx: TaskRunContext, inputs: dict[str, Any], flow_parameters: dict[str, Any], **kwargs: Any) -> Optional[str]

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CacheKeyFnPolicy

This policy accepts a custom function with signature f(task_run_context, task_parameters, flow_parameters) -> str and uses it to compute a task run cache key.

Methods:

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compute_key

compute_key(self, task_ctx: TaskRunContext, inputs: dict[str, Any], flow_parameters: dict[str, Any], **kwargs: Any) -> Optional[str]

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CompoundCachePolicy

This policy is constructed from two or more other cache policies and works by computing the keys for each policy individually, and then hashing a sorted tuple of all computed keys.

Any keys that return None will be ignored.

Methods:

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compute_key

compute_key(self, task_ctx: TaskRunContext, inputs: dict[str, Any], flow_parameters: dict[str, Any], **kwargs: Any) -> Optional[str]

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TaskSource

Policy for computing a cache key based on the source code of the task.

This policy only considers raw lines of code in the task, and not the source code of nested tasks.

Methods:

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compute_key

compute_key(self, task_ctx: TaskRunContext, inputs: Optional[dict[str, Any]], flow_parameters: Optional[dict[str, Any]], **kwargs: Any) -> Optional[str]

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FlowParameters

Policy that computes the cache key based on a hash of the flow parameters.

Methods:

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compute_key

compute_key(self, task_ctx: TaskRunContext, inputs: dict[str, Any], flow_parameters: dict[str, Any], **kwargs: Any) -> Optional[str]

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RunId

Returns either the prevailing flow run ID, or if not found, the prevailing task run ID.

Methods:

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compute_key

compute_key(self, task_ctx: TaskRunContext, inputs: dict[str, Any], flow_parameters: dict[str, Any], **kwargs: Any) -> Optional[str]

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Inputs

Policy that computes a cache key based on a hash of the runtime inputs provided to the task..

Methods:

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compute_key

compute_key(self, task_ctx: TaskRunContext, inputs: dict[str, Any], flow_parameters: dict[str, Any], **kwargs: Any) -> Optional[str]