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https://github.com/kubernetes-sigs/external-dns.git
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5d54849699
* Endpoint.Target is now Endpoint.Targets. This is its own type representing mutliple targets for a single DNS name while adding some convenience for sorting and comparing * Made everything compile and tests run through with the new Endpoint.Targets * The ingress source can now properly handle multiple target ips per host * Added custom conflict resolver, to better understand how conflict resolution has to work for me * My custom conflict resolver behaves a bit different than the PerResource resolver, therefore I needed to modify the expected test result Removed unnecessary FIXME * The ingress source now creates CNAME endpoints with multiple targets to let the DNS provider decide how to handle multiple CNAME targets. This could be interesting for weighted targets etc. * Adopted the expected results to the new way we create endpoints for CNAMEs * Removed Add method from Targets since manipulating the slice through here is unnecessary complicated and doesn't deliver enough convenience * Reverted ConflictResolver to the original one. There is some discussing to do what the best way is to handle conflicts * Added missing documenting comment to IsLess of Targets * Added documenting comments to Targets,Targets.Same and NewTargets to clarify their intention and usage * Service source now also generates endpoints with multiple targets * Service and Ingress source now sort all Targets for every Endpoint to make order of Targets predictable * Endpoints generated by the Google Cloud DNS provider now also have sorted Targets to make order of Targets predictable * Modified provider dyn to be able to compile with multi target changes * Fixed small nitpicks, so my code is acceptable * Fixed merge method after updating to new Targets. Replacing '!=' with .Same of course needs a boolean negation * Tests for dyn provider now also use the new Targets instead of Target * Simplified extractServiceIps as implied by linki to make it more readable * ref: change service ClusterIP retrieval again * Added entry to CHANGELOG.md describing the new features contained in this PR
71 lines
2.6 KiB
Go
71 lines
2.6 KiB
Go
/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package plan
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import (
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"sort"
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"github.com/kubernetes-incubator/external-dns/endpoint"
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)
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// ConflictResolver is used to make a decision in case of two or more different kubernetes resources
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// are trying to acquire same DNS name
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type ConflictResolver interface {
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ResolveCreate(candidates []*endpoint.Endpoint) *endpoint.Endpoint
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ResolveUpdate(current *endpoint.Endpoint, candidates []*endpoint.Endpoint) *endpoint.Endpoint
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}
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// PerResource allows only one resource to own a given dns name
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type PerResource struct{}
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// ResolveCreate is invoked when dns name is not owned by any resource
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// ResolveCreate takes "minimal" (string comparison of Target) endpoint to acquire the DNS record
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func (s PerResource) ResolveCreate(candidates []*endpoint.Endpoint) *endpoint.Endpoint {
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var min *endpoint.Endpoint
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for _, ep := range candidates {
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if min == nil || s.less(ep, min) {
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min = ep
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}
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}
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return min
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}
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// ResolveUpdate is invoked when dns name is already owned by "current" endpoint
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// ResolveUpdate uses "current" record as base and updates it accordingly with new version of same resource
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// if it doesn't exist then pick min
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func (s PerResource) ResolveUpdate(current *endpoint.Endpoint, candidates []*endpoint.Endpoint) *endpoint.Endpoint {
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currentResource := current.Labels[endpoint.ResourceLabelKey] // resource which has already acquired the DNS
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// TODO: sort candidates only needed because we can still have two endpoints from same resource here. We sort for consistency
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// TODO: remove once single endpoint can have multiple targets
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sort.SliceStable(candidates, func(i, j int) bool {
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return s.less(candidates[i], candidates[j])
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})
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for _, ep := range candidates {
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if ep.Labels[endpoint.ResourceLabelKey] == currentResource {
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return ep
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}
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}
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return s.ResolveCreate(candidates)
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}
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// less returns true if endpoint x is less than y
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func (s PerResource) less(x, y *endpoint.Endpoint) bool {
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return x.Targets.IsLess(y.Targets)
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}
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// TODO: with cross-resource/cross-cluster setup alternative variations of ConflictResolver can be used
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