This document describes the current stable version of Kombu (5.0). For development docs, go here.
Functional-style Utilities - kombu.utils.functional
¶
Functional Utilities.
-
class
kombu.utils.functional.
LRUCache
(limit=None)[source]¶ LRU Cache implementation using a doubly linked list to track access.
- Parameters
limit (int) – The maximum number of keys to keep in the cache. When a new key is inserted and the limit has been exceeded, the Least Recently Used key will be discarded from the cache.
-
iteritems
()¶
-
iterkeys
()¶
-
itervalues
()¶
-
popitem
() → (k, v), remove and return some (key, value) pair[source]¶ as a 2-tuple; but raise KeyError if D is empty.
-
kombu.utils.functional.
dictfilter
(d=None, **kw)[source]¶ Remove all keys from dict
d
whose value isNone
.
-
kombu.utils.functional.
is_list
(obj, scalars=(<class 'collections.abc.Mapping'>, <class 'str'>), iters=(<class 'collections.abc.Iterable'>, ))[source]¶ Return true if the object is iterable.
Note
Returns false if object is a mapping or string.
-
class
kombu.utils.functional.
lazy
(fun, *args, **kwargs)[source]¶ Holds lazy evaluation.
Evaluated when called or if the
evaluate()
method is called. The function is re-evaluated on every call.- Overloaded operations that will evaluate the promise:
__str__()
,__repr__()
,__cmp__()
.
-
kombu.utils.functional.
maybe_evaluate
(value)[source]¶ Evaluate value only if value is a
lazy
instance.
-
kombu.utils.functional.
maybe_list
(obj, scalars=(<class 'collections.abc.Mapping'>, <class 'str'>))[source]¶ Return list of one element if
l
is a scalar.
-
kombu.utils.functional.
memoize
(maxsize=None, keyfun=None, Cache=<class 'kombu.utils.functional.LRUCache'>)[source]¶ Decorator to cache function return value.
-
kombu.utils.functional.
retry_over_time
(fun, catch, args=None, kwargs=None, errback=None, max_retries=None, interval_start=2, interval_step=2, interval_max=30, callback=None, timeout=None)[source]¶ Retry the function over and over until max retries is exceeded.
For each retry we sleep a for a while before we try again, this interval is increased for every retry until the max seconds is reached.
- Parameters
fun (Callable) – The function to try
catch (Tuple[BaseException]) – Exceptions to catch, can be either tuple or a single exception class.
- Keyword Arguments
args (Tuple) – Positional arguments passed on to the function.
kwargs (Dict) – Keyword arguments passed on to the function.
errback (Callable) – Callback for when an exception in
catch
is raised. The callback must take three arguments:exc
,interval_range
andretries
, whereexc
is the exception instance,interval_range
is an iterator which return the time in seconds to sleep next, andretries
is the number of previous retries.max_retries (int) – Maximum number of retries before we give up. If neither of this and timeout is set, we will retry forever. If one of this and timeout is reached, stop.
interval_start (float) – How long (in seconds) we start sleeping between retries.
interval_step (float) – By how much the interval is increased for each retry.
interval_max (float) – Maximum number of seconds to sleep between retries.
timeout (int) – Maximum seconds waiting before we give up.