Add experimental ready feature

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

cmd/ready.go

@@ -0,0 +1,104 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"time"
+
+	execute "github.com/alexellis/go-execute/pkg/v1"
+	"github.com/alexellis/k3sup/pkg"
+	"github.com/spf13/cobra"
+)
+
+func MakeReady() *cobra.Command {
+	var command = &cobra.Command{
+		Use:   "ready",
+		Short: "Check if a cluster is ready using kubectl.",
+		Long: `Check if the K3s cluster is ready using kubectl to query the nodes.
+
+` + pkg.SupportMessageShort + `
+`,
+		Example: `  # Check from a local file, with the context "default"
+  k3sup ready \
+    --context default \
+    --kubeconfig ./kubeconfig
+
+  # Check a merged kubeconfig with a custom context
+  k3sup ready \
+    --context e2e \
+    --kubeconfig $HOME/.kube/config
+`,
+		SilenceUsage: true,
+	}
+
+	command.Flags().Int("attempts", 25, "Number of attempts to check for readiness")
+	command.Flags().Duration("pause", time.Second*2, "Pause between checking cluster for readiness")
+	command.Flags().String("kubeconfig", "$HOME/.kube/config", "Path to the kubeconfig file")
+	command.Flags().String("context", "default", "Name of the kubeconfig context to use")
+
+	command.RunE = func(cmd *cobra.Command, args []string) error {
+
+		attempts, _ := cmd.Flags().GetInt("attempts")
+		pause, _ := cmd.Flags().GetDuration("pause")
+		kubeconfig, _ := cmd.Flags().GetString("kubeconfig")
+		contextName, _ := cmd.Flags().GetString("context")
+
+		if len(kubeconfig) == 0 {
+			return fmt.Errorf("kubeconfig cannot be empty")
+		}
+
+		if len(contextName) == 0 {
+			return fmt.Errorf("context cannot be empty")
+		}
+
+		kubeconfig = os.ExpandEnv(kubeconfig)
+
+		// Inspired by Kind: https://github.com/kubernetes-sigs/kind/blob/master/pkg/cluster/internal/create/actions/waitforready/waitforready.go
+		for i := 0; i < attempts; i++ {
+			fmt.Printf("Checking cluster status: %d/%d \n", i+1, attempts)
+			task := execute.ExecTask{
+				Command: "kubectl",
+				Args: []string{
+					"get",
+					"nodes",
+					"--kubeconfig=" + kubeconfig,
+					"--context=" + contextName,
+					"-o=jsonpath='{.items..status.conditions[-1:].status}'",
+				},
+				StreamStdio: false,
+			}
+			res, err := task.Execute()
+			if err != nil {
+				return err
+			}
+			// fmt.Println(res.Stdout, res.Stderr, res.ExitCode)
+
+			if res.ExitCode == 0 {
+				fmt.Printf("Cluster is ready\n")
+				return nil
+			}
+
+			if strings.Contains(res.Stderr, "context was not found") {
+				return fmt.Errorf("context %s not found in %s", contextName, kubeconfig)
+			}
+
+			parts := strings.Split(res.Stdout, " ")
+			ready := true
+			for _, part := range parts {
+				trimmed := strings.TrimSpace(part)
+				if len(trimmed) > 0 && trimmed != "True" {
+					ready = false
+				}
+			}
+
+			if ready {
+				break
+			}
+			time.Sleep(pause)
+		}
+
+		return nil
+	}
+	return command
+}

main.go

@@ -14,6 +14,7 @@ func main() {
 	cmdVersion := cmd.MakeVersion()
 	cmdJoin := cmd.MakeJoin()
 	cmdUpdate := cmd.MakeUpdate()
+	cmdReady := cmd.MakeReady()
 
 	printk3supASCIIArt := cmd.PrintK3supASCIIArt
 
@@ -52,6 +53,7 @@ func main() {
 	rootCmd.AddCommand(cmdVersion)
 	rootCmd.AddCommand(cmdJoin)
 	rootCmd.AddCommand(cmdUpdate)
+	rootCmd.AddCommand(cmdReady)
 
 	if err := rootCmd.Execute(); err != nil {
 		os.Exit(1)