| For this ticket we'll need to add a new metric to the mq-metrics-registry found in command.cl_j. The metric will likely need to be updated in the do-enqueue-command func where it acquires a token from the _write-semaphore. Each command should inc this metric before attempting to acquire the token and dec the metric once the token is acquired. Acceptance criteria: * An added metric to the mq-metrics-registry which tracks the number of commands waiting to acquire a token from the write semaphore at any given time. * A test which shows that this metric increases and decreases as expected. Testing notes: It may be useful to override the concurrent-writes setting during the test and set it to one. Then using with-redefs or some other method to pause command processing in the do-enqueue-command func after an incoming command has acquired the one token from the write-semaphore we should be able to submit more commands which will block on the (.acquire write-semaphore) call. Once the system is in this state we can check that the metric was updated properly. We should also check that once all the commands are allowed to be processed the metric drops to a zero value. |
