Hi Hussein, for your information, today we added a description of task and operator lifecycles to the documentation: https://ci.apache.org/projects/flink/flink-docs-release-1.3/internals/task_lifecycle.html <https://ci.apache.org/projects/flink/flink-docs-release-1.3/internals/task_lifecycle.html> .
Best, Stefan > Am 03.03.2017 um 15:30 schrieb Tzu-Li (Gordon) Tai <tzuli...@apache.org>: > > Hi Hussein! > > Your approach seems reasonable to me. The open() method will be called only > once for the UDF every time the job has started (and when the job is restored > from failures also). > > Cheers, > Gordon > > On March 3, 2017 at 7:03:22 PM, Hussein Baghdadi (hussein.baghd...@zalando.de > <mailto:hussein.baghd...@zalando.de>) wrote: > >> Hello, >> >> In our Sink, we are dealing with a system that uses OAuth 2.0. So the in the >> open() method of the Sink we are getting the token and then we initialise >> the client that we can use in order to write from Flink to that API. >> >> Is there a better approach to handle that? >> >> open() is a lifecycle method which I assume it will be called only once when >> creating a Sink, correct? Are there any conditions that might trigger open() >> to be called not upon creations? >> >> Thanks a lot for your help and time.