Flush on search custom command not working

[rleoneti]

I try to use flush on custom command and not working.

I used generatetext.py from searchcommands_app and put self.flush() and the search done with errors.

    def generate(self):
        text = self.text
        self.logger.debug("Generating %d events with text %s" % (self.count, self.text))
        for i in range(1, self.count + 1):
            yield {'_serial': i, '_time': time.time(), '_raw': six.text_type(i) + '. ' + text}
            self.flush()

Error:

02-20-2020 14:32:12.814 INFO  ReducePhaseExecutor - ReducePhaseExecutor=1 action=PREVIEW
02-20-2020 14:32:12.990 INFO  ReducePhaseExecutor - ReducePhaseExecutor=1 action=PREVIEW
02-20-2020 14:32:12.990 ERROR ChunkedExternProcessor - Failed to write buffer of size 17 to external process file descriptor (The pipe is being closed.)
02-20-2020 14:32:13.024 ERROR ChunkedExternProcessor - Failure writing result chunk, buffer full. External process possibly failed to read its stdin.
02-20-2020 14:32:13.024 ERROR ChunkedExternProcessor - Error in 'generatetext' command: Failed to send message to external search command, see search.log.
02-20-2020 14:32:13.024 INFO  ReducePhaseExecutor - Ending phase_1
02-20-2020 14:32:13.024 INFO  UserManager - Unwound user context: admin -> NULL
02-20-2020 14:32:13.024 ERROR SearchOrchestrator - Phase_1 failed due to : Error in 'generatetext' command: Failed to send message to external search command, see search.log.
02-20-2020 14:32:13.025 INFO  ReducePhaseExecutor - ReducePhaseExecutor=1 action=CANCEL
02-20-2020 14:32:13.025 INFO  DispatchExecutor - User applied action=CANCEL while status=0
02-20-2020 14:32:13.025 ERROR SearchStatusEnforcer - sid:1582219925.18 Error in 'generatetext' command: Failed to send message to external search command, see search.log.
02-20-2020 14:32:13.025 INFO  SearchStatusEnforcer - State changed to FAILED due to: Error in 'generatetext' command: Failed to send message to external search command, see search.log.
02-20-2020 14:32:13.090 INFO  UserManager - Unwound user context: admin -> NULL

Any Help ??