class DeferredList(Deferred[_DeferredListResultListT]): (source)
DeferredList
is a tool for collecting the results of several Deferreds.
This tracks a list of Deferred
s for their results, and makes a single callback when they have all completed. By default, the ultimate result is a list of (success, result) tuples, 'success' being a boolean. DeferredList
exposes the same API that Deferred
does, so callbacks and errbacks can be added to it in the same way.
DeferredList
is implemented by adding callbacks and errbacks to each Deferred
in the list passed to it. This means callbacks and errbacks added to the Deferreds before they are passed to DeferredList
will change the result that DeferredList
sees (i.e., DeferredList
is not special). Callbacks and errbacks can also be added to the Deferreds after they are passed to DeferredList
and DeferredList
may change the result that they see.
See the documentation for the __init__ arguments for more information.
Method | __init__ |
Initialize a DeferredList. |
Method | cancel |
Cancel this DeferredList . |
Instance Variable | consumeErrors |
Undocumented |
Instance Variable | finishedCount |
Undocumented |
Instance Variable | fireOnOneCallback |
Undocumented |
Instance Variable | fireOnOneErrback |
Undocumented |
Instance Variable | resultList |
No summary |
Method | _cbDeferred |
(internal) Callback for when one of my deferreds fires. |
Instance Variable | _deferredList |
The list of Deferred s to track. |
Parameters | |
deferredList:Iterable[ | The deferreds to track. |
fireOnOneCallback:bool | (keyword param) a flag indicating that this DeferredList will fire when the first Deferred in deferredList fires with a non-failure result without waiting for any of the other Deferreds. When this flag is set, the DeferredList will fire with a two-tuple: the first element is the result of the Deferred which fired; the second element is the index in deferredList of that Deferred. |
fireOnOneErrback:bool | (keyword param) a flag indicating that this DeferredList will fire when the first Deferred in deferredList fires with a failure result without waiting for any of the other Deferreds. When this flag is set, if a Deferred in the list errbacks, the DeferredList will errback with a FirstError failure wrapping the failure of that Deferred. |
consumeErrors:bool | (keyword param) a flag indicating that failures in any of the included Deferred s should not be propagated to errbacks added to the individual Deferred s after this DeferredList is constructed. After constructing the DeferredList , any errors in the individual Deferred s will be converted to a callback result of None . This is useful to prevent spurious 'Unhandled error in Deferred' messages from being logged. This does not prevent fireOnOneErrback from working. |
Cancel this DeferredList
.
If the DeferredList
hasn't fired yet, cancel every Deferred
in the list.
If the DeferredList
has fired, including the case where the fireOnOneCallback/fireOnOneErrback flag is set and the DeferredList
fires because one Deferred
in the list fires with a non-failure/failure result, do nothing in the cancel method.
Deferred
at the same position in _deferredList
. It will be None
if the Deferred
did not complete yet, or a (success, result) pair if it did.Parameters | |
result:_DeferredResultT | Undocumented |
index:int | Undocumented |
succeeded:bool | Undocumented |
Returns | |
Optional[ | Undocumented |