---
title: cache_policies
sidebarTitle: cache_policies
---

# `prefect.cache_policies`

## Classes

### `CachePolicy` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L46" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


Base class for all cache policies.


**Methods:**

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L99" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `configure` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L68" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
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.


#### `from_cache_key_fn` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L60" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Given a function generates a key policy.


### `CacheKeyFnPolicy` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L155" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


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:**

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L166" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L99" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `configure` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L68" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
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.


#### `from_cache_key_fn` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L60" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Given a function generates a key policy.


### `CompoundCachePolicy` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L178" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


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:**

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L205" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L99" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `configure` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L68" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
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.


#### `from_cache_key_fn` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L60" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Given a function generates a key policy.


### `TaskSource` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L278" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


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:**

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L285" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L99" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `configure` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L68" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
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.


#### `from_cache_key_fn` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L60" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Given a function generates a key policy.


### `FlowParameters` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L307" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


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


**Methods:**

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L312" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L99" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `configure` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L68" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
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.


#### `from_cache_key_fn` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L60" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Given a function generates a key policy.


### `RunId` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L325" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


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


**Methods:**

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L331" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L99" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `configure` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L68" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
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.


#### `from_cache_key_fn` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L60" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Given a function generates a key policy.


### `Inputs` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L347" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>


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


**Methods:**

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L354" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `compute_key` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L99" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

#### `configure` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L68" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

```python
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.


#### `from_cache_key_fn` <sup><a href="https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cache_policies.py#L60" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a></sup>

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

Given a function generates a key policy.

