add hidden 'get join-command' command for embedded-cluster (#5280)

* add hidden 'get join-command' command for embedded-cluster

* update unit test code

check error codes, test error code handling in both requests

Author: laverya

cmd/kots/cli/get-joincommand.go

@@ -0,0 +1,192 @@
+package cli
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/replicatedhq/kots/pkg/api/handlers/types"
+	"github.com/replicatedhq/kots/pkg/auth"
+	"github.com/replicatedhq/kots/pkg/k8sutil"
+	"github.com/spf13/cobra"
+	"github.com/spf13/viper"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+)
+
+func GetJoinCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:           "join-command",
+		Short:         "Get embedded cluster join command",
+		Long:          "",
+		SilenceUsage:  false,
+		SilenceErrors: false,
+		Hidden:        true,
+		PreRun: func(cmd *cobra.Command, args []string) {
+			viper.BindPFlags(cmd.Flags())
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			v := viper.GetViper()
+
+			clientset, err := k8sutil.GetClientset()
+			if err != nil {
+				return fmt.Errorf("failed to get clientset: %w", err)
+			}
+
+			namespace, err := getNamespaceOrDefault(v.GetString("namespace"))
+			if err != nil {
+				return fmt.Errorf("failed to get namespace: %w", err)
+			}
+
+			joinCmd, err := getJoinCommandCmd(cmd.Context(), clientset, namespace)
+			if err != nil {
+				return err
+			}
+
+			format := v.GetString("output")
+			if format == "string" || format == "" {
+				fmt.Println(strings.Join(joinCmd, " "))
+				return nil
+			} else if format == "json" {
+				type joinCommandResponse struct {
+					Command []string `json:"command"`
+				}
+				joinCmdResponse := joinCommandResponse{
+					Command: joinCmd,
+				}
+				b, err := json.Marshal(joinCmdResponse)
+				if err != nil {
+					return fmt.Errorf("failed to marshal join command: %w", err)
+				}
+				fmt.Println(string(b))
+				return nil
+			}
+
+			return fmt.Errorf("invalid output format: %s", format)
+		},
+	}
+	cmd.Flags().StringP("output", "o", "", "output format (currently supported: json)")
+
+	return cmd
+}
+
+func getJoinCommandCmd(ctx context.Context, clientset kubernetes.Interface, namespace string) ([]string, error) {
+	// determine the IP address and port of the kotsadm service
+	// this only runs inside an embedded cluster and so we don't need to setup port forwarding
+	svc, err := clientset.CoreV1().Services(namespace).Get(ctx, "kotsadm", metav1.GetOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("unable to get kotsadm service: %w", err)
+	}
+	kotsadmIP := svc.Spec.ClusterIP
+	if kotsadmIP == "" {
+		return nil, fmt.Errorf("kotsadm service ip was empty")
+	}
+
+	if len(svc.Spec.Ports) == 0 {
+		return nil, fmt.Errorf("kotsadm service ports were empty")
+	}
+	kotsadmPort := svc.Spec.Ports[0].Port
+
+	authSlug, err := auth.GetOrCreateAuthSlug(clientset, namespace)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get kotsadm auth slug: %w", err)
+	}
+
+	url := fmt.Sprintf("http://%s:%d/api/v1/embedded-cluster/roles", kotsadmIP, kotsadmPort)
+	roles, err := getRoles(url, authSlug)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get roles: %w", err)
+	}
+
+	controllerRole := roles.ControllerRoleName
+	if controllerRole == "" && len(roles.Roles) > 0 {
+		controllerRole = roles.Roles[0]
+	}
+	if controllerRole == "" {
+		return nil, fmt.Errorf("unable to determine controller role name")
+	}
+
+	// get a join command with the controller role with a post to /api/v1/embedded-cluster/generate-node-join-command
+	url = fmt.Sprintf("http://%s:%d/api/v1/embedded-cluster/generate-node-join-command", kotsadmIP, kotsadmPort)
+	joinCommand, err := getJoinCommand(url, authSlug, []string{controllerRole})
+	if err != nil {
+		return nil, fmt.Errorf("failed to get join command: %w", err)
+	}
+
+	return joinCommand.Command, nil
+}
+
+// determine the embedded cluster roles list from /api/v1/embedded-cluster/roles
+func getRoles(url string, authSlug string) (*types.GetEmbeddedClusterRolesResponse, error) {
+	newReq, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+	newReq.Header.Add("Content-Type", "application/json")
+	newReq.Header.Add("Authorization", authSlug)
+
+	resp, err := http.DefaultClient.Do(newReq)
+	if err != nil {
+		return nil, fmt.Errorf("failed to execute request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
+	}
+
+	b, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response body: %w", err)
+	}
+
+	roles := &types.GetEmbeddedClusterRolesResponse{}
+	if err := json.Unmarshal(b, roles); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal roles: %w", err)
+	}
+
+	return roles, nil
+}
+
+func getJoinCommand(url string, authSlug string, roles []string) (*types.GenerateEmbeddedClusterNodeJoinCommandResponse, error) {
+	payload := types.GenerateEmbeddedClusterNodeJoinCommandRequest{
+		Roles: roles,
+	}
+	b, err := json.Marshal(payload)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal roles: %w", err)
+	}
+
+	newReq, err := http.NewRequest("POST", url, bytes.NewBuffer(b))
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+	newReq.Header.Add("Content-Type", "application/json")
+	newReq.Header.Add("Authorization", authSlug)
+
+	resp, err := http.DefaultClient.Do(newReq)
+	if err != nil {
+		return nil, fmt.Errorf("failed to execute request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
+	}
+
+	fullResponse, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read response body: %w", err)
+	}
+
+	joinCommand := &types.GenerateEmbeddedClusterNodeJoinCommandResponse{}
+	if err := json.Unmarshal(fullResponse, joinCommand); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal roles: %w", err)
+	}
+
+	return joinCommand, nil
+}