Refactor this logic so that it can be more easily tested and expanded
without cluttering the pod.go file. Additionally, add some safe guards
around the pod cast to ensure that we're working with pods before we
pass them.
Previously, kube-router would do a full sync on a new pod whether or not
the pod was in an actionable state. This led to needless syncs as many
pods were missing PodIP addresses or other items necessary to apply
policy.
If a pod is missing these items it is better to wait for the next
message that comes via the UpdateFunc below so that we know that the pod
has all of the necessary items to apply policy to it.
With the previous logic, if a pod changed from having HostNetwork =
False to HostNetwork = True, NPC would not trigger a refresh to clear
out the rules that once applied. Now this check has been moved lower in
the fullPolicySync() logic so that it accounts for these pods naturally.
Check if the Pod is actionable before taking NetworkPolicy actions which
includes both adding KUBE-POD-FW and KUBE-NWPLCY chains for it.
Checks have now been consolidated to a single isNetPolActionable()
function which checks for pod phases that we don't want NetworkPolicy
for like: Failed, Completed, and Succeeded, missing pod IP addresses,
and pods with HostNetwork enabled.
fixes#1056
