fix(slr): address family and familypolicy isn't correct

[SkalaNetworks]

Pull Request

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What type of this PR

Bug fix on the SwitchLBRules.

The ipFamilies and ipFamilyPolicy aren't honored for the VIP. Because the clusterIP isn't set, K8S determines the family using its defaults.

So if the cluster was installed with a ServiceCIDR that contains the IPv4 range first and the IPv6 second, the family will be set to IPv4 by default. This works in nearly every case.

But if the ServiceCIDR contains the IPv6 range first and the IPv4 range second, the Service is created with ipFamily IPv6, eventhough the VIP might be an IPv4. This breaks the SLR and no endpoint is generated for the service.

The VIP might contain IPv4/IPv6 or a mix of the two. Depending on the content of the VIP, we detect if the Service should be created with ipFamilies IPv4, IPv6 or both. We also compute the ipFamilyPolicy to SingleStack or Dual depending on the number of ipFamilies.

[gemini-code-assist]

Summary of Changes

Hello @SkalaNetworks, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request fixes a bug in the SwitchLBRule controller where the generated Kubernetes Service was not correctly configured with the appropriate IP families and family policy based on the specified VIP. This could lead to the Service being created with the wrong address family in dual-stack clusters, preventing endpoints from being generated. The changes introduce logic to dynamically determine the correct IP families and policy by inspecting the VIP string and apply these settings to the Service, ensuring compatibility with the provided VIP addresses.

Highlights

• Bug Fix: SwitchLBRule IP Families: I've addressed a bug where the ipFamilies and ipFamilyPolicy for the Service created by a SwitchLBRule were not being correctly determined based on the VIP, potentially causing issues in dual-stack environments depending on the ServiceCIDR order.
• Dynamic IP Family Detection: Introduced a new helper function getIPFamilies that inspects the provided VIP string (which can contain comma-separated IPs) to determine if it includes IPv4, IPv6, or both, and sets the appropriate IPFamilies slice and IPFamilyPolicy (SingleStack or PreferDualStack).
• Service Update Logic: Modified the generateHeadlessService function to call the new getIPFamilies helper and apply the determined families and policy to the Service spec, both when creating a new Service and updating an existing one.
• IP Protocol Helper: Added a utility function GetIPAddressProtocol in pkg/util/address_family.go to reliably determine if a given IP string is IPv4 or IPv6 using the standard net package.
• Unit Tests: Added unit tests for the new getIPFamilies function to cover single-stack (IPv4, IPv6) and dual-stack (IPv6 then IPv4, IPv4 then IPv6) scenarios.

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[gemini-code-assist]

Code Review

The pull request fixes an issue where the IP family and family policy for SwitchLBRule services were not being set accurately. The core change involves a new utility function getIPFamilies to determine the appropriate settings based on the VIP's IP addresses, and applying these to the generated Kubernetes Service. A critical issue was identified in the new helper function util.GetIPAddressProtocol which could lead to a panic with invalid IP inputs, and a fix is suggested. Additionally, enhancing the test coverage for getIPFamilies with edge cases for VIP strings would improve robustness. A minor typo in a test error message was also noted.

[coveralls]

Pull Request Test Coverage Report for Build 15605457341

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 14 of 24 (58.33%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 21.755%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/controller/switch_lb_rule.go	14	24	58.33%

Totals
Change from base Build 15605224454:	0.02%
Covered Lines:	10441
Relevant Lines:	47993

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💛 - Coveralls