rabbitmqctl shovel_status: handle metrics

[dcorbacho]

The rabbitmqctl command got broken a while back when metrics were added to the status e3430aa
The command stopped reporting any status.

This PR addresses that, and as we have the metrics available, we just include them in the status.

I don't think e3430aa made it into any release, otherwise this PR needs backporting.

[ikavgo]

how it was discovered? there is status command suite and it was green IIRC...

yeah last commit in that PR was green - #13620

Point I'm making - looks like that SUITE was not enough, maybe worth adding test?

[dcorbacho]

Just using it. The command would never return anything.

The test suite is not an end to end test, it skips all the formatting part and that is where the issue is. A test which used rabbitmqctl shovel_status with any shovel would have detected it.

[michaelklishin]

The failures are not flakes:

shovel_status_command_SUITE > non_parallel_tests > output_starting
    #1. {error,
            {{badmatch,{stream,[]}},
             [{shovel_status_command_SUITE,output_starting,1,
                  [{file,"shovel_status_command_SUITE.erl"},{line,97}]},
              {test_server,ts_tc,3,[{file,"test_server.erl"},{line,1796}]},
              {test_server,run_test_case_eval1,6,
                  [{file,"test_server.erl"},{line,1305}]},
              {test_server,run_test_case_eval,9,
                  [{file,"test_server.erl"},{line,1237}]}]}}

shovel_status_command_SUITE > non_parallel_tests > output_running
    #1. {error,
            {{badmatch,{stream,[]}},
             [{shovel_status_command_SUITE,output_running,1,
                  [{file,"shovel_status_command_SUITE.erl"},{line,117}]},
              {test_server,ts_tc,3,[{file,"test_server.erl"},{line,1796}]},
              {test_server,run_test_case_eval1,6,
                  [{file,"test_server.erl"},{line,1305}]},
              {test_server,run_test_case_eval,9,
                  [{file,"test_server.erl"},{line,1237}]}]}}

[michaelklishin]

This PR will be backported for 4.1.4.