Add a barrier constraining execution order for notifications. #22
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Update the batch call test to verify that the reply to a batch containing a notification correctly omits the notification.
This test exercises the problem described in #20, where notification handlers can issue out of order relative to their receipt. At this commit the test fails.
When issuing a batch of requests, keep track of the number that are valid notifications, and do not issue to any handler for the batch until all notifications received in previous batches have completed. This ensures a sensible partial order on notifications. Multiple notifications in a single batch can still be executed in parallel, but notifications across batches are no longer concurrent.
When the channel to the client closes, the server discards any calls that are pending in the queue, but retains notifications. The logic for pruning the queue was incorrect, and would handle items in the wrong order.
The server fully transmits a response to the client before updating metrics. In the unit test, this means the client can observe the request to complete before the metrics are actually updated. This causes occasional spurious test failures in the check for metrics being updated: Spurious, because the metric DOES get updated, just not immediately. Avert this issue by fully shutting down the server before doing any of the metric checks. No functional changes.
Add a section to the main doc page about order of execution. Clarify that concurrency does not constrain issue.
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An attempt to address #20.
When issuing a batch of requests, keep track of the number that are valid notifications, and do not issue to any handler for the batch until all notifications received in previous batches have completed.
This ensures a sensible partial order on notifications. Multiple notifications in a single batch can still be executed in parallel, but notifications across batches are no longer concurrent.
Before merging: