Adds CreateNetworkStatuses for CNI results with multiple pod interfaces

[dougbtv]

Essentially, the gist is that the current singular CreateNetworkStatus method isn't aware of CNI results that have multiple pod interfaces returned.

This approach adds a new method (to not break current implementations, as it needs to return a list instead of a single Network Status)

With the existing method, this is somewhat buggy. If multiple pod interfaces are present, it returns the last one -- and groups all of the IP addresses to that address.

This method returns a list, still limited to interface results that have the sandbox present, and it maps the IPs to the interface using the ips.interface index property in the CNI result.

From the spec (in ADD Success):

sandbox (string): The isolation domain reference (e.g. path to network namespace) for the interface, or empty if on the host. For interfaces created inside the container, this should be the value passed via CNI_NETNS.

For replication of the error yourself, and to see the fix in action, see this gist: https://gist.github.com/dougbtv/1eb8ac2d61d494b56d65a6b236a86e61

For the related suggested update to the NPWG net-attach-def specification, see this proposal @ https://docs.google.com/document/d/1DUTV-o6E6zlRTKZkxeDhAeyGrmq03qPgPbU580Rm7-g/edit

[maiqueb]

Just some minor nits.

Thanks for the unit tests; they are very readable.

[maiqueb]

maybe name this defaultRoutes ?

[dougbtv]

thanks, cool, I like it, I'm going with useDefaultRoute as I'm setting it to be used in the loop following it (instead of calculating it there)

[maiqueb]

I don't understand the reasoning :)

Sorry. But again, this is just a nit you can ignore.

[dougbtv]

I guess I'm thinking it's because you "use" the same default route across interfaces in these CNI results, they apply to all the interfaces in the result, so you wind up re-using them. So, I'm going with the half/half, half of what I started with, half what you suggested haha

[maiqueb]

nit: let's be consistent and use camel case everywhere

Suggested change

	for _, ipconfig := range result.IPs {
	for _, ipConfig := range result.IPs {

[maiqueb]

we must rename this variable. I have no clue what is it supposed to track.

Is it supposed to track the number of interfaces on the pod ? (i.e. the ones w/ sandbox defined)

[dougbtv]

Yeah, good suggestion -- this is the trickiest bit of code, I renamed it to indexOfFoundPodInterface because it's this thing where we have to map the interfaces that we keep (pod interfaces) to the index as in the CNI result

[dougbtv]

Review super appreciated! New commit up, thanks

[maiqueb]

Thank you.