Don't ask for sorted results from RabbitMQ

[binarin]

E.g. for 10000 queues performing the sort using the default sorting
order costs ~0.3 second on my machine.

Now that rabbitmq/rabbitmq-management#369 is
merged we can avoid this cost. This change is backward compatible, for older versions of RabbitMQ adding empty sort parameter will result in using the default sort order(vhost, name)

[kbudde]

Hi,

very nice addition and I like it. Unfortunately it is not backward compatible. The empty sort paramater fails in rabbitmq 3.5 and earlier. See the error message below.

Adding a space to the sort will work with 3.4+.
config.RabbitURL+"/api/"+endpoint+"?sort=%20"

Can you say/verify that this will disabling sort in the latest rabbitmq version? Perhaps we are lucky and the parameter is trimmed.
I do not want to break with 3.4 and 3.5 for the moment.

{ error: "Internal Server Error", reason: "{error,{error,function_clause, [{rabbit_mgmt_util,get_dotted_value0, [[], [{name,<<"amq.direct">>}, {vhost,<<"/">>}, {type,direct}, {durable,true}, {auto_delete,false}, {internal,false}, {arguments,{struct,[]}}, {policy,<<"ha-2">>}]], []}, {rabbit_mgmt_util,sort_key,2,[]}, {rabbit_mgmt_util,'-sort_list/4-lc$^1/1-1-',2,[]}, {rabbit_mgmt_util,sort_list,4,[]}, {rabbit_mgmt_util,reply_list,4,[]}, {webmachine_resource,resource_call,3,[]}, {webmachine_resource,do,3,[]}, {webmachine_decision_core,resource_call,1,[]}]}} " }

[binarin]

Yeah, I've forgot about cowboy switch in 3.6, so currently this is only compatible with 3.6 and 3.7.

I'll add a config option for explicitly enabling new behavior

[binarin]

I've updated my code, now this no-sort functionality should be explicitly enabled.

The reason for using map to track the supported capabilities (instead of simple bool) is that I'm going to add at least one other optional feature - rabbitmq/rabbitmq-management#367

[kbudde]

Hi,

I've merged it into the develop branch. Docker image was created (tag: develop).
I will do some more tests and merge it aferwards.

LGTM