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thunderboltsidthunderboltsid
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feat(api): Add kubernetes version to coredns version mapping
Added script and makefile target to update coredns version mapping. `make coredns.sync` will fetch the list of releases from upstream release branches and create a mapping k8s releases to coredns versions.
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‎api/versions/coredns.go

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‎hack/tools/coredns-versions/main.go

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package main
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import (
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"bytes"
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"encoding/json"
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"errors"
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"flag"
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"fmt"
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"go/format"
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"io"
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"net/http"
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"os"
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"path"
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"regexp"
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"sort"
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"strings"
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"text/template"
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"golang.org/x/mod/semver"
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)
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var (
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// Command-line flags
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outputFile = flag.String("output", "api/versions/coredns.go", "Output file path")
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minKubernetesVersion = flag.String("min-kubernetes-version", "v1.22", "Minimum Kubernetes version to include (semver format)")
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)
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const (
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constantsURLTemplate = "https://raw.githubusercontent.com/kubernetes/kubernetes/%s/cmd/kubeadm/app/constants/constants.go"
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branchesAPIURL = "https://api.github.com/repos/kubernetes/kubernetes/branches?per_page=100&page=%d"
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)
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var goTemplate = `// Code generated by script; DO NOT EDIT. Run 'make coredns.sync' instead
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package versions
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// Kubernetes versions
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const (
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{{- range .KubernetesConstants }}
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{{ .Name }} = "{{ .Version }}"
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{{- end }}
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)
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// CoreDNS versions
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const (
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{{- range .CoreDNSConstants }}
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{{ .Name }} = "{{ .Version }}"
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{{- end }}
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)
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// KubernetesToCoreDNSVersion maps Kubernetes versions to CoreDNS versions.
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var KubernetesToCoreDNSVersion = map[string]string{
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{{- range .VersionMap }}
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{{ .KubernetesConst }}: {{ .CoreDNSConst }},
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{{- end }}
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}
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`
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func main() {
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flag.Parse()
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// Ensure minKubernetesVersion is in semver format (prefixed with 'v')
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if !strings.HasPrefix(*minKubernetesVersion, "v") {
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*minKubernetesVersion = "v" + *minKubernetesVersion
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}
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versions, err := fetchKubernetesVersions(*minKubernetesVersion)
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if err != nil {
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fmt.Fprintf(os.Stderr, "Error fetching Kubernetes versions: %v\n", err)
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os.Exit(1)
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}
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versionMap, err := fetchCoreDNSVersions(versions)
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if err != nil {
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fmt.Fprintf(os.Stderr, "Error fetching CoreDNS versions: %v\n", err)
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os.Exit(1)
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}
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if err := generateGoFile(versionMap, *outputFile); err != nil {
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fmt.Fprintf(os.Stderr, "Error generating Go file: %v\n", err)
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os.Exit(1)
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}
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fmt.Printf("Successfully generated %s\n", *outputFile)
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}
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// Fetch Kubernetes versions from GitHub branches
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func fetchKubernetesVersions(minVersion string) ([]string, error) {
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var versions []string
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page := 1
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for {
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url := fmt.Sprintf(branchesAPIURL, page)
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branchNames, err := fetchBranchNames(url)
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if err != nil {
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return nil, err
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}
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if len(branchNames) == 0 {
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break
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}
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for _, branch := range branchNames {
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if strings.HasPrefix(branch, "release-1.") {
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version := strings.TrimPrefix(branch, "release-")
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semverVersion := "v" + version
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if semver.Compare(semverVersion, minVersion) >= 0 {
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versions = append(versions, version)
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}
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}
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}
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page++
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}
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if len(versions) == 0 {
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return nil, errors.New("no Kubernetes versions found")
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}
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// Remove duplicates and sort
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versionSet := make(map[string]struct{})
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for _, v := range versions {
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versionSet[v] = struct{}{}
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}
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versions = nil
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for v := range versionSet {
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versions = append(versions, v)
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}
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sort.Slice(versions, func(i, j int) bool {
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return semver.Compare("v"+versions[i], "v"+versions[j]) < 0
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})
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return versions, nil
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}
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// Fetch branch names from GitHub API
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func fetchBranchNames(url string) ([]string, error) {
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resp, err := http.Get(url)
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if err != nil {
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return nil, fmt.Errorf("HTTP GET error: %w", err)
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return nil, fmt.Errorf("non-200 HTTP status: %d", resp.StatusCode)
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}
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var branches []struct {
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Name string `json:"name"`
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}
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if err := json.NewDecoder(resp.Body).Decode(&branches); err != nil {
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return nil, fmt.Errorf("decoding JSON error: %w", err)
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}
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var branchNames []string
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for _, branch := range branches {
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branchNames = append(branchNames, branch.Name)
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}
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return branchNames, nil
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}
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func fetchCoreDNSVersions(versions []string) (map[string]string, error) {
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versionMap := make(map[string]string)
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re := regexp.MustCompile(`CoreDNSVersion\s*=\s*"([^"]+)"`)
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for _, k8sVersion := range versions {
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branch := "release-" + k8sVersion
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url := fmt.Sprintf(constantsURLTemplate, branch)
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coreDNSVersion, err := extractCoreDNSVersion(url, re)
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if err != nil {
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fmt.Fprintf(os.Stderr, "Warning: Failed for Kubernetes %s: %v\n", k8sVersion, err)
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continue
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}
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versionMap[k8sVersion] = coreDNSVersion
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}
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if len(versionMap) == 0 {
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return nil, errors.New("no CoreDNS versions found")
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}
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return versionMap, nil
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}
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func extractCoreDNSVersion(url string, re *regexp.Regexp) (string, error) {
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resp, err := http.Get(url)
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if err != nil {
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return "", fmt.Errorf("HTTP GET error: %w", err)
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return "", fmt.Errorf("non-200 HTTP status: %d", resp.StatusCode)
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}
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bodyBytes, err := io.ReadAll(resp.Body)
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if err != nil {
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return "", fmt.Errorf("reading body error: %w", err)
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}
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matches := re.FindStringSubmatch(string(bodyBytes))
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if len(matches) != 2 {
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return "", errors.New("CoreDNSVersion not found")
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}
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return matches[1], nil
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}
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func generateGoFile(versionMap map[string]string, outputPath string) error {
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data := prepareTemplateData(versionMap)
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tmpl, err := template.New("versionMapping").Parse(goTemplate)
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if err != nil {
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return fmt.Errorf("parsing template error: %w", err)
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}
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var buf bytes.Buffer
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if err := tmpl.Execute(&buf, data); err != nil {
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return fmt.Errorf("executing template error: %w", err)
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}
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formattedSrc, err := format.Source(buf.Bytes())
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if err != nil {
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return fmt.Errorf("formatting source code error: %w", err)
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}
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if err := os.MkdirAll(path.Dir(outputPath), os.ModePerm); err != nil {
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return fmt.Errorf("creating directories error: %w", err)
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}
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if err := os.WriteFile(outputPath, formattedSrc, 0644); err != nil {
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return fmt.Errorf("writing file error: %w", err)
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}
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return nil
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}
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func prepareTemplateData(versionMap map[string]string) map[string]interface{} {
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type Const struct {
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Name string
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Version string
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}
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var k8sConstants []Const
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var coreDNSConstants []Const
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type versionMapEntry struct {
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KubernetesVersion string
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KubernetesConst string
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CoreDNSConst string
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}
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var versionMapList []versionMapEntry
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// Maps for deduplication
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k8sConstMap := make(map[string]string)
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coreDNSConstMap := make(map[string]string)
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// Collect unique CoreDNS versions
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uniqueCoreDNSVersions := make(map[string]struct{})
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for _, coreDNSVersion := range versionMap {
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uniqueCoreDNSVersions[coreDNSVersion] = struct{}{}
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}
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// Generate constants for Kubernetes versions
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for k8sVersion := range versionMap {
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constName := versionToConst("Kubernetes", k8sVersion)
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k8sConstMap[k8sVersion] = constName
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}
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// Generate constants for CoreDNS versions
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for coreDNSVersion := range uniqueCoreDNSVersions {
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constName := versionToConst("CoreDNS", coreDNSVersion)
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coreDNSConstMap[coreDNSVersion] = constName
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}
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// Prepare constants slices
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for k8sVersion, constName := range k8sConstMap {
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k8sConstants = append(k8sConstants, Const{Name: constName, Version: k8sVersion})
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}
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for coreDNSVersion, constName := range coreDNSConstMap {
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coreDNSConstants = append(coreDNSConstants, Const{Name: constName, Version: coreDNSVersion})
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}
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// Sort constants
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sort.Slice(k8sConstants, func(i, j int) bool {
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return semver.Compare("v"+k8sConstants[i].Version, "v"+k8sConstants[j].Version) < 0
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})
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sort.Slice(coreDNSConstants, func(i, j int) bool {
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return semver.Compare(coreDNSConstants[i].Version, coreDNSConstants[j].Version) < 0
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})
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// Map Kubernetes constants to CoreDNS constants
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for k8sVersion, coreDNSVersion := range versionMap {
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versionMapList = append(versionMapList, versionMapEntry{
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KubernetesVersion: k8sVersion,
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KubernetesConst: k8sConstMap[k8sVersion],
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CoreDNSConst: coreDNSConstMap[coreDNSVersion],
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})
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}
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// Sort version map
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sort.Slice(versionMapList, func(i, j int) bool {
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return semver.Compare("v"+versionMapList[i].KubernetesVersion, "v"+versionMapList[j].KubernetesVersion) < 0
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})
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data := map[string]interface{}{
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"KubernetesConstants": k8sConstants,
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"CoreDNSConstants": coreDNSConstants,
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"VersionMap": versionMapList,
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}
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return data
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}
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func versionToConst(prefix, version string) string {
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// Remove 'v' prefix if present
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version = strings.TrimPrefix(version, "v")
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// Replace dots with underscores
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version = strings.ReplaceAll(version, ".", "_")
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// Prepend the prefix and 'V'
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return prefix + "_V" + version
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}

‎make/apis.mk

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@@ -55,3 +55,8 @@ api.sync.%: ; $(info $(M) syncing external API: $(PROVIDER_MODULE_$*)/$(PROVIDER
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$(PROVIDER_API_DIR)
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find $(PROVIDER_API_DIR) -type d -exec chmod 0755 {} \;
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find $(PROVIDER_API_DIR) -type f -exec chmod 0644 {} \;
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.PHONY: coredns.sync
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coredns.sync: ## Syncs the Kubernetes version to CoreDNS version mapping used in the cluster upgrade
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coredns.sync: ; $(info $(M) syncing CoreDNS version mapping)
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go run hack/tools/coredns-versions/main.go

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