/
coredns.go
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/
coredns.go
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/*
* Tencent is pleased to support the open source community by making TKEStack available.
*
* Copyright (C) 2012-2020 Tencent. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use
* this file except in compliance with the License. You may obtain a copy of the
* License at
*
* https://opensource.org/licenses/Apache-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OF ANY KIND, either express or implied. See the License for the
* specific language governing permissions and limitations under the License.
*/
package util
import (
"context"
"encoding/json"
"sync"
"tkestack.io/tke/pkg/util/apiclient"
"tkestack.io/tke/pkg/util/log"
"github.com/caddyserver/caddy/caddyfile"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes"
)
const (
DNS = ".:53"
REWRITE = "rewrite"
NAME = "name"
CoreFileKey = "Corefile"
KubeSystem = "kube-system"
ConfigMapName = "coredns"
TargetSVC = "tke-registry-api.tke.svc.cluster.local"
)
type CoreFileBlock struct {
Body [][]string `json:"body"`
Keys []string `json:"keys"`
}
type CoreFile []*CoreFileBlock
type CoreFileHosts [][]string
type CoreDNS struct {
sync.Mutex
configMap *corev1.ConfigMap
kubeClient *kubernetes.Clientset
}
func NewCoreDNS() (*CoreDNS, error) {
kubeClient, err := apiclient.BuildKubeClient()
if err != nil {
return nil, err
}
return &CoreDNS{
kubeClient: kubeClient,
}, nil
}
func (c *CoreDNS) LoadCoreFile() []byte {
coreDNSConfigMap, err := c.kubeClient.CoreV1().ConfigMaps(KubeSystem).Get(context.Background(),
ConfigMapName, metav1.GetOptions{})
if err != nil {
log.Error("get coredns's configmap failed", log.Err(err))
return nil
}
c.configMap = coreDNSConfigMap
return []byte(coreDNSConfigMap.Data[CoreFileKey])
}
func (c *CoreDNS) StoreCoreFile(content []byte) {
c.configMap.Data[CoreFileKey] = string(content)
_, err := c.kubeClient.CoreV1().ConfigMaps(KubeSystem).Update(context.Background(), c.configMap, metav1.UpdateOptions{})
if err != nil {
log.Error("update coredns's configmap failed", log.Err(err))
}
}
func (c *CoreDNS) ParseCoreFile(item string) {
c.Lock()
defer c.Unlock()
content := c.LoadCoreFile()
if content == nil {
return
}
coreFileBody, _ := caddyfile.ToJSON(content)
coreFileObj := new(CoreFile)
_ = json.Unmarshal(coreFileBody, coreFileObj)
for _, block := range *coreFileObj {
if c.ParseBlockDNS(block, item) {
break
}
}
coreFileBody, _ = json.Marshal(coreFileObj)
content, _ = caddyfile.FromJSON(coreFileBody)
c.StoreCoreFile(content)
}
func (c *CoreDNS) ParseBlockDNS(block *CoreFileBlock, item string) bool {
if block.Keys == nil || len(block.Keys) == 0 || block.Keys[0] != DNS {
return false
}
findItem := false
for _, s := range block.Body {
if c.ParseSectionRewrite(s, item) {
findItem = true
break
}
}
if !findItem {
block.Body = append(block.Body, []string{REWRITE, NAME, item, TargetSVC})
}
return true
}
func (c *CoreDNS) ParseSectionRewrite(section []string, item string) bool {
if section == nil || len(section) != 4 || section[0] != REWRITE {
return false
}
if section[2] == item {
section[3] = TargetSVC
return true
}
return false
}