[GitHub] [pulsar-client-cpp] zbentley opened a new issue, #86: Attempting to connect a consumer to a very recently created topic/subscription sometimes fails with UnknownError on the client

[GitBox <gi...@apache.org>]

zbentley opened a new issue, #86:
URL: https://github.com/apache/pulsar-client-cpp/issues/86

   **Describe the bug**
   If I create a topic/subscription via the management API and then immediately attempt to connect a consumer to that subscription via the C++ client, the `subscribe` call *sometimes* (rarely; less than half of the time) fails with `UnknownError`. 
   
   This error does not coincide with any obvious issues in the broker or proxy log; sorry for the light detail on this bug.
   
   
   **To Reproduce**
   Run reproduction plan for https://github.com/apache/pulsar/issues/12551; sometimes no error will occur, sometimes  the error described in that issue or others will occur, and sometimes this error will occur during the last step (connecting a consumer).
   
   **Expected behavior**
   1. Consumer connection either succeeds or fails with an informative error indicating what action is needed to correct this condition.
   2. This is probably more important: interactions with Pulsar (e.g. creating consumers) that happen a very short time after the entities being interacted with (topics/subscriptions in this case) should succeed; . This bug and the other similar ones I filed (see github links below) all seem to arise from CRUD operations with the management API being asynchronous: i.e. when I create/delete a tenant/topic/namespace, the actual side effects of that creation or deletion (e.g. adding/removing ledgers in BookKeeper, updating metadata in ZK) occur later, not during the API post. Not only is that bound to cause bugs like this, but it's also not what users expect; I would be happy to wait seconds or minutes for management API operations to complete in exchange for knowing that when they successfully complete that the thing I requested has actually been done.
   
   **Client logs**
   ```
   [persistent://blt6/chariot_ns_test/chariot_topic_test-partition-1, blt, 1] Failed to create consumer: UnknownError
   Closing the consumer failed for partition - 1
   Unable to create Consumer for partition - 1 Error - UnknownError
   Closing the consumer failed for partition - 0
   [persistent://blt6/chariot_ns_test/chariot_topic_test-partition-3, blt, 3] Failed to close consumer: ConnectError
   ```
   
   This error is surfaced in Python (client version 2.8.1, on EKS amazon linux) as `UnknownError`.


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