Auto-populated protocol-specific tagged addresses do not respect default tags

[freddygv]

We currently populate the tagged addresses for ipv4 and ipv6 from the service address if the service address is ipv4/6 and there is no existing address tagged as wan_ipv4/6.

That means that if someone adds a plain wan tagged address, the wan_ipv4/6 will be inherited from the service address and not the user-provided wan address.

Repro steps:

0. consul agent -dev
1. consul connect envoy -gateway=mesh -register -wan-address 192.168.0.4:8080 -address '{{ GetInterfaceIP "en0" }}'
2. curl http://127.0.0.1:8500/v1/agent/services

Notice that the wan and wan_ipv4 addresses differ.

One potential solution here is to revert the tagged address defaulting in addServiceInternal that was added in #6640. This way only addresses specified by the user are present in the TaggedAddresses map. Modifying a provided service registration has been surprising to some users.

[freddygv]

@pierresouchay do you have any thoughts about this?

[pierresouchay]

@ShimmerGlass Any opinion on this?

[ShimmerGlass]

This looks like an oversight in the original PR. Reverting the change would indeed solve the issue, but would be a step back for dual-stack support in Consul which is needed in our shop. Additionally, the wan_ipv{4,6} fields are pretty new and I would be surprised if many people use them already.

I see two ways to fix that :

• Store the source for each tagged address, if a more specific one comes along, override it as needed. Eg: first populate wan_ipv4 from address, if wan_address is specified wan_ipv4 get overridden.
• Apply the addresses in more-specific to less specific order: wan_address is applied first and populates wan_ipv4, address is applied but doesn't change wan_ipv4 because it is already set.

[andrewoelfing]

Hello @pierresouchay, hello @ShimmerGlass, could this commit be a possible solution? At least it fixes the problem with the incorrect/differing WAN IP

[ShimmerGlass]

@andrewoelfing It might, do you handle the case where the WAN address is a domain, not an IP?

[andrewoelfing]

Hello @ShimmerGlass, the documentation says the parameter only takes ip and port (or go-sockaddr templates).
Consul-Connect#wan-address

[freddygv]

Hi @andrewoelfing, thank you for the reference commit. After taking a look at this I think it's preferable to address this bug in the agent code rather than in the connect sub-command because it affects all service registrations (as well as the lan tag, which I missed when I created this issue).

I pushed a PR to address this issue.