Control the Cloud C++ client library behavior with respect to polling on long running operations.
Some operations in Cloud services return agoogle.longrunning.Operationobject. As their name implies, these objects represent requests that may take a long time to complete, in some cases operations may take tens of seconds or even 30 minutes to complete.
The Cloud C++ client libraries models these long running operations as agoogle::cloud::future<StatusOr<T>>, whereTrepresents the final result of the operation. In the background, the library polls the service until the operation completes (or fails) and then satisfies the future.
This class defines the interface for policies that control the behavior of this polling loop.
This function is called at the beginning of the polling loop. Policies that are based on relative time should restart their timers when this function is called.
Returns
Type
Description
std::unique_ptr< PollingPolicy >
OnFailure(Status const &)
A callback to indicate that a polling attempt failed.
This is called when a polling request fails. Note that this callback is not invoked when the polling request succeeds with "operation not done".
Parameter
Name
Description
status
Status const &
Returns
Type
Description
bool
true if the failure should be treated as transient and the polling loop should continue.
WaitPeriod()
How long should the polling loop wait before trying again.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eThis page details the \u003ccode\u003ePollingPolicy\u003c/code\u003e class within the Google Cloud C++ client library, which controls how long-running operations are polled for completion.\u003c/p\u003e\n"],["\u003cp\u003eThe library models long-running operations using \u003ccode\u003egoogle::cloud::future<StatusOr<T>>\u003c/code\u003e, automatically polling the service in the background until the operation is finished.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003ePollingPolicy\u003c/code\u003e class offers methods such as \u003ccode\u003eclone()\u003c/code\u003e, \u003ccode\u003eOnFailure()\u003c/code\u003e, and \u003ccode\u003eWaitPeriod()\u003c/code\u003e to manage polling behavior, including copying the policy, handling failures, and setting the wait time between polling attempts.\u003c/p\u003e\n"],["\u003cp\u003eThe latest version of the documentated reference is 2.37.0-rc, with a full list of previous versions available for viewing.\u003c/p\u003e\n"],["\u003cp\u003eThe document is related to polling on long-running operations that may take a long period of time to complete, and the \u003ccode\u003ePollingPolicy\u003c/code\u003e class has been designed to help manage this.\u003c/p\u003e\n"]]],[],null,["# Class PollingPolicy (2.24.0)\n\nVersion 2.24.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.41.0](/cpp/docs/reference/common/2.41.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.40.0](/cpp/docs/reference/common/2.40.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.39.0](/cpp/docs/reference/common/2.39.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.38.0](/cpp/docs/reference/common/2.38.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.37.0](/cpp/docs/reference/common/2.37.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.36.0](/cpp/docs/reference/common/2.36.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.35.0](/cpp/docs/reference/common/2.35.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.34.0](/cpp/docs/reference/common/2.34.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.33.0](/cpp/docs/reference/common/2.33.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.32.0](/cpp/docs/reference/common/2.32.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.31.0](/cpp/docs/reference/common/2.31.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.30.0](/cpp/docs/reference/common/2.30.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.29.0](/cpp/docs/reference/common/2.29.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.28.0](/cpp/docs/reference/common/2.28.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.27.0](/cpp/docs/reference/common/2.27.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.26.0](/cpp/docs/reference/common/2.26.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.25.1](/cpp/docs/reference/common/2.25.1/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.24.0](/cpp/docs/reference/common/2.24.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.23.0](/cpp/docs/reference/common/2.23.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.22.1](/cpp/docs/reference/common/2.22.1/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.21.0](/cpp/docs/reference/common/2.21.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.20.0](/cpp/docs/reference/common/2.20.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.19.0](/cpp/docs/reference/common/2.19.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.18.0](/cpp/docs/reference/common/2.18.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.17.0](/cpp/docs/reference/common/2.17.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.16.0](/cpp/docs/reference/common/2.16.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.15.1](/cpp/docs/reference/common/2.15.1/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.14.0](/cpp/docs/reference/common/2.14.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.13.0](/cpp/docs/reference/common/2.13.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.12.0](/cpp/docs/reference/common/2.12.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.11.0](/cpp/docs/reference/common/2.11.0/classgoogle_1_1cloud_1_1PollingPolicy)\n- [2.10.1](/cpp/docs/reference/common/2.10.1/classgoogle_1_1cloud_1_1PollingPolicy) \nControl the Cloud C++ client library behavior with respect to polling on long running operations. \nSome operations in Cloud services return a `google.longrunning.Operation` object. As their name implies, these objects represent requests that may take a long time to complete, in some cases operations may take tens of seconds or even 30 minutes to complete.\n\nThe Cloud C++ client libraries models these long running operations as a [`google::cloud::future`](/cpp/docs/reference/common/2.24.0/classgoogle_1_1cloud_1_1future)`\u003c`[`StatusOr`](/cpp/docs/reference/common/2.24.0/classgoogle_1_1cloud_1_1StatusOr)`\u003cT\u003e\u003e`, where `T` represents the final result of the operation. In the background, the library polls the service until the operation completes (or fails) and then satisfies the future.\n\nThis class defines the interface for policies that control the behavior of this polling loop.\n\n###### See Also\n\n\u003chttps://aip.dev/151\u003e for more information on long running operations.\n\nFunctions\n---------\n\n### clone() const\n\nReturn a copy of the current policy. \nThis function is called at the beginning of the polling loop. Policies that are based on relative time should restart their timers when this function is called.\n\n### OnFailure(Status const \\&)\n\nA callback to indicate that a polling attempt failed. \nThis is called when a polling request fails. Note that this callback is not invoked when the polling request succeeds with \"operation not done\".\n\n### WaitPeriod()\n\nHow long should the polling loop wait before trying again."]]
