Caching utilities

class commons.caching.TimedCache(*, global_ttl: timedelta | None = None, lazy_eviction: bool = True, ttl_from_last_access: bool = False)

__init__(*, global_ttl: timedelta | None = None, lazy_eviction: bool = True, ttl_from_last_access: bool = False)

Parameters:

• global_ttl (Optional[timedelta]) – A default TTL for any added entries.

• lazy_eviction (bool) –

  Whether this cache should perform lazy eviction or not.

  Defaults to True

• ttl_from_last_access (bool) –

  Whether the TTL of an object is dictated by the last access or time of insertion.

  This requires a global TTL to be set.

  Defaults to True, time of insertion.

add_entry(key: KT, value: VT, *, ttl: timedelta | None = None, override: bool = False) → None

Add an entry to the cache.

Parameters:

• key – The key to store this under.

• value – The item you want to store in the cache

• ttl (Optional[timedelta]) – An optional period of time to expire this entry after.

• override (bool) – Whether or not to override an existing value

Raises:

ExistingEntry – You are trying to insert a duplicate key

Notes

ttl passed to this method will take precendence over the global ttl.

delete_entry(key: KT) → None

Delete a key from the cache

Parameters:

key – The key to delete

force_clean() → None

Clear out all outdated cache items.

get_entry(key: KT) → VT

Fetch a value from the cache

Parameters:

key – The key you wish to retrieve a value for

Returns:

The provided value

Return type:

VT

Raises:

NonExistentEntry – No value exists in the cache for the provided key.

class commons.caching.Entry(value: Any, expiry_time: datetime.datetime | None = None)

class commons.caching.NonExistentEntry

No entry found in the cache with this key.

class commons.caching.ExistingEntry

An entry was already found in the cache with this key.