Simplify kubeconfig retrieval by using k0s kubeconfig command (#720)

* Simplify kubeconfig retrieval by using k0s kubeconfig command

Signed-off-by: Kimmo Lehto <[email protected]>

* Restore --kubeconfig-api-address functionality

Signed-off-by: Kimmo Lehto <[email protected]>

---------

Signed-off-by: Kimmo Lehto <[email protected]>

Author: kke

phase/get_kubeconfig.go

@@ -4,10 +4,9 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/k0sproject/dig"
-	"github.com/k0sproject/k0sctl/pkg/apis/k0sctl.k0sproject.io/v1beta1/cluster"
+	"github.com/k0sproject/rig/exec"
+	log "github.com/sirupsen/logrus"
 	"gopkg.in/yaml.v2"
-	"k8s.io/client-go/tools/clientcmd"
 )
 
 // GetKubeconfig is a phase to get and dump the admin kubeconfig
@@ -16,108 +15,51 @@ type GetKubeconfig struct {
 	APIAddress string
 }
 
+type kubeconfig struct {
+	Clusters []struct {
+		Cluster struct {
+			Server string `yaml:"server"`
+		} `yaml:"cluster"`
+	} `yaml:"clusters"`
+}
+
 // Title for the phase
 func (p *GetKubeconfig) Title() string {
 	return "Get admin kubeconfig"
 }
 
-var readKubeconfig = func(h *cluster.Host) (string, error) {
-	return h.Configurer.ReadFile(h, h.Configurer.KubeconfigPath(h, h.K0sDataDir()))
-}
-
-var k0sConfig = func(h *cluster.Host) (dig.Mapping, error) {
-	cfgContent, err := h.Configurer.ReadFile(h, h.Configurer.K0sConfigPath())
-	if err != nil {
-		return nil, fmt.Errorf("read k0s config from host: %w", err)
-	}
-
-	var cfg dig.Mapping
-	if err := yaml.Unmarshal([]byte(cfgContent), &cfg); err != nil {
-		return nil, fmt.Errorf("unmarshal k0s config: %w", err)
-	}
-
-	if err != nil {
-		return nil, fmt.Errorf("parse k0s config: %w", err)
-	}
-
-	return cfg, nil
-}
-
 func (p *GetKubeconfig) DryRun() error {
 	p.DryMsg(p.Config.Spec.Hosts.Controllers()[0], "get admin kubeconfig")
 	return nil
 }
 
 // Run the phase
 func (p *GetKubeconfig) Run() error {
-	h := p.Config.Spec.Hosts.Controllers()[0]
-
-	cfg, err := k0sConfig(h)
-	if err != nil {
-		return err
-	}
+	h := p.Config.Spec.K0sLeader()
 
-	output, err := readKubeconfig(h)
+	output, err := h.ExecOutput(h.Configurer.K0sCmdf("kubeconfig admin"), exec.Sudo(h))
 	if err != nil {
 		return fmt.Errorf("read kubeconfig from host: %w", err)
 	}
 
-	if p.APIAddress == "" {
-		// the controller admin.conf is aways pointing to localhost, thus we need to change the address
-		// something usable from outside
-		address := h.Address()
-		if a, ok := cfg.Dig("spec", "api", "externalAddress").(string); ok && a != "" {
-			address = a
+	if p.APIAddress != "" {
+		log.Debugf("%s: replacing api address with %v", h, p.APIAddress)
+		kubeconf := kubeconfig{}
+		if err := yaml.Unmarshal([]byte(output), &kubeconf); err != nil {
+			return fmt.Errorf("unmarshal kubeconfig: %w", err)
 		}
-
-		port := 6443
-		if p, ok := cfg.Dig("spec", "api", "port").(int); ok && p != 0 {
-			port = p
+		if len(kubeconf.Clusters) == 0 {
+			return fmt.Errorf("no clusters found in kubeconfig")
 		}
-
-		if strings.Contains(address, ":") {
-			p.APIAddress = fmt.Sprintf("https://[%s]:%d", address, port)
-		} else {
-			p.APIAddress = fmt.Sprintf("https://%s:%d", address, port)
+		server := kubeconf.Clusters[0].Cluster.Server
+		if server == "" {
+			return fmt.Errorf("no server found in kubeconfig")
 		}
+		log.Debugf("%s: replacing %v with %v", h, server, p.APIAddress)
+		output = strings.ReplaceAll(output, server, p.APIAddress)
 	}
 
-	cfgString, err := kubeConfig(output, p.Config.Metadata.Name, p.APIAddress)
-	if err != nil {
-		return err
-	}
-
-	p.Config.Metadata.Kubeconfig = cfgString
+	p.Config.Metadata.Kubeconfig = output
 
 	return nil
 }
-
-// kubeConfig reads in the raw kubeconfig and changes the given address
-// and cluster name into it
-func kubeConfig(raw string, name string, address string) (string, error) {
-	cfg, err := clientcmd.Load([]byte(raw))
-	if err != nil {
-		return "", err
-	}
-
-	cfg.Clusters[name] = cfg.Clusters["local"]
-	delete(cfg.Clusters, "local")
-	cfg.Clusters[name].Server = address
-
-	cfg.Contexts[name] = cfg.Contexts["Default"]
-	delete(cfg.Contexts, "Default")
-	cfg.Contexts[name].Cluster = name
-	cfg.Contexts[name].AuthInfo = "admin"
-
-	cfg.CurrentContext = name
-
-	cfg.AuthInfos["admin"] = cfg.AuthInfos["user"]
-	delete(cfg.AuthInfos, "user")
-
-	out, err := clientcmd.Write(*cfg)
-	if err != nil {
-		return "", err
-	}
-
-	return string(out), nil
-}