mirror of https://github.com/k3s-io/k3s
81 lines
2.7 KiB
Go
81 lines
2.7 KiB
Go
/*
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Copyright 2019 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 proxy
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import (
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v1 "k8s.io/api/core/v1"
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)
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// FilterTopologyEndpoint returns the appropriate endpoints based on the cluster
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// topology.
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// This uses the current node's labels, which contain topology information, and
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// the required topologyKeys to find appropriate endpoints. If both the endpoint's
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// topology and the current node have matching values for topologyKeys[0], the
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// endpoint will be chosen. If no endpoints are chosen, toplogyKeys[1] will be
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// considered, and so on. If either the node or the endpoint do not have values
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// for a key, it is considered to not match.
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//
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// If topologyKeys is specified, but no endpoints are chosen for any key, the
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// the service has no viable endpoints for clients on this node, and connections
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// should fail.
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//
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// The special key "*" may be used as the last entry in topologyKeys to indicate
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// "any endpoint" is acceptable.
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//
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// If topologyKeys is not specified or empty, no topology constraints will be
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// applied and this will return all endpoints.
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func FilterTopologyEndpoint(nodeLabels map[string]string, topologyKeys []string, endpoints []Endpoint) []Endpoint {
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// Do not filter endpoints if service has no topology keys.
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if len(topologyKeys) == 0 {
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return endpoints
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}
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filteredEndpoint := []Endpoint{}
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if len(nodeLabels) == 0 {
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if topologyKeys[len(topologyKeys)-1] == v1.TopologyKeyAny {
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// edge case: include all endpoints if topology key "Any" specified
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// when we cannot determine current node's topology.
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return endpoints
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}
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// edge case: do not include any endpoints if topology key "Any" is
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// not specified when we cannot determine current node's topology.
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return filteredEndpoint
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}
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for _, key := range topologyKeys {
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if key == v1.TopologyKeyAny {
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return endpoints
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}
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topologyValue, found := nodeLabels[key]
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if !found {
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continue
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}
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for _, ep := range endpoints {
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topology := ep.GetTopology()
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if value, found := topology[key]; found && value == topologyValue {
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filteredEndpoint = append(filteredEndpoint, ep)
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}
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}
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if len(filteredEndpoint) > 0 {
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return filteredEndpoint
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}
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}
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return filteredEndpoint
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}
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