[SCB-1079]allow consumer-id to be empty when query instance

[liubao68]

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[coveralls]

Coverage decreased (-0.004%) to 86.696% when pulling a83f380 on liubao68:reg-instance into bd6a2c4 on apache:master.

[yhs0092]

Hi @liubao68
As far as I know, we treat service-id of the consumer as the consumer-id. So there seems no possibility that the consumer-id is null, as long as the consumer service instance is registered in service-center properly.
Or the service-id mechanism will also be changed?

[liubao68]

@yhs0092 consumer-id is null when the startup procedure is in progress (BEFORE_REGISTRY), the service-id is not registered to service-center or we have not quried service-id from service-center. This feature is for scenarios that users want to do some extra control before register himself. e.g. Registry before querie service center that some dependeded service exists.

[yhs0092]

@liubao68 OK, get it.