Merge pull request #66 from andyz-dev/bash

[Feature] Add Bash shell support

cli/cluster.go

@@ -1,8 +1,10 @@
 package run
 
 import (
+	"bytes"
 	"context"
 	"fmt"
+	"io/ioutil"
 	"log"
 	"os"
 	"path"
@@ -85,6 +87,94 @@ func getClusterDir(name string) (string, error) {
 	return path.Join(homeDir, ".config", "k3d", name), nil
 }
 
+func getClusterKubeConfigPath(cluster string) (string, error) {
+	clusterDir, err := getClusterDir(cluster)
+	return path.Join(clusterDir, "kubeconfig.yaml"), err
+}
+
+func createKubeConfigFile(cluster string) error {
+	ctx := context.Background()
+	docker, err := client.NewEnvClient()
+	if err != nil {
+		return err
+	}
+
+	filters := filters.NewArgs()
+	filters.Add("label", "app=k3d")
+	filters.Add("label", fmt.Sprintf("cluster=%s", cluster))
+	filters.Add("label", "component=server")
+	server, err := docker.ContainerList(ctx, types.ContainerListOptions{
+		Filters: filters,
+	})
+
+	if err != nil {
+		return fmt.Errorf("Failed to get server container for cluster %s\n%+v", cluster, err)
+	}
+
+	if len(server) == 0 {
+		return fmt.Errorf("No server container for cluster %s", cluster)
+	}
+
+	// get kubeconfig file from container and read contents
+	reader, _, err := docker.CopyFromContainer(ctx, server[0].ID, "/output/kubeconfig.yaml")
+	if err != nil {
+		return fmt.Errorf("ERROR: couldn't copy kubeconfig.yaml from server container %s\n%+v", server[0].ID, err)
+	}
+	defer reader.Close()
+
+	readBytes, err := ioutil.ReadAll(reader)
+	if err != nil {
+		return fmt.Errorf("ERROR: couldn't read kubeconfig from container\n%+v", err)
+	}
+
+	// create destination kubeconfig file
+	destPath, err := getClusterKubeConfigPath(cluster)
+	if err != nil {
+		return err
+	}
+
+	kubeconfigfile, err := os.Create(destPath)
+	if err != nil {
+		return fmt.Errorf("ERROR: couldn't create kubeconfig file %s\n%+v", destPath, err)
+	}
+	defer kubeconfigfile.Close()
+
+	// write to file, skipping the first 512 bytes which contain file metadata and trimming any NULL characters
+	_, err = kubeconfigfile.Write(bytes.Trim(readBytes[512:], "\x00"))
+	if err != nil {
+		return fmt.Errorf("ERROR: couldn't write to kubeconfig.yaml\n%+v", err)
+	}
+
+	return nil
+}
+
+func getKubeConfig(cluster string) (string, error) {
+	kubeConfigPath, err := getClusterKubeConfigPath(cluster)
+	if err != nil {
+		return "", err
+	}
+
+	if clusters, err := getClusters(false, cluster); err != nil || len(clusters) != 1 {
+		if err != nil {
+			return "", err
+		}
+		return "", fmt.Errorf("Cluster %s does not exist", cluster)
+	}
+
+	// If kubeconfi.yaml has not been created, generate it now
+	if _, err := os.Stat(kubeConfigPath); err != nil {
+		if os.IsNotExist(err) {
+			if err = createKubeConfigFile(cluster); err != nil {
+				return "", err
+			}
+		} else {
+			return "", err
+		}
+	}
+
+	return kubeConfigPath, nil
+}
+
 // printClusters prints the names of existing clusters
 func printClusters() {
 	clusters, err := getClusters(true, "")

cli/commands.go

@@ -9,15 +9,12 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"strconv"
 	"strings"
 	"time"
 
-	"github.com/docker/docker/api/types/filters"
-
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/client"
 	"github.com/urfave/cli"
@@ -346,61 +343,21 @@ func ListClusters(c *cli.Context) error {
 
 // GetKubeConfig grabs the kubeconfig from the running cluster and prints the path to stdout
 func GetKubeConfig(c *cli.Context) error {
-	ctx := context.Background()
-	docker, err := client.NewEnvClient()
-	if err != nil {
-		return err
-	}
-
-	filters := filters.NewArgs()
-	filters.Add("label", "app=k3d")
-	filters.Add("label", fmt.Sprintf("cluster=%s", c.String("name")))
-	filters.Add("label", "component=server")
-	server, err := docker.ContainerList(ctx, types.ContainerListOptions{
-		Filters: filters,
-	})
-
-	if err != nil {
-		return fmt.Errorf("Failed to get server container for cluster %s\n%+v", c.String("name"), err)
-	}
-
-	if len(server) == 0 {
-		return fmt.Errorf("No server container for cluster %s", c.String("name"))
-	}
-
-	// get kubeconfig file from container and read contents
-	reader, _, err := docker.CopyFromContainer(ctx, server[0].ID, "/output/kubeconfig.yaml")
-	if err != nil {
-		return fmt.Errorf("ERROR: couldn't copy kubeconfig.yaml from server container %s\n%+v", server[0].ID, err)
-	}
-	defer reader.Close()
-
-	readBytes, err := ioutil.ReadAll(reader)
-	if err != nil {
-		return fmt.Errorf("ERROR: couldn't read kubeconfig from container\n%+v", err)
-	}
-
-	// create destination kubeconfig file
-	clusterDir, err := getClusterDir(c.String("name"))
-	destPath := fmt.Sprintf("%s/kubeconfig.yaml", clusterDir)
+	cluster := c.String("name")
+	kubeConfigPath, err := getKubeConfig(cluster)
 	if err != nil {
 		return err
 	}
 
-	kubeconfigfile, err := os.Create(destPath)
-	if err != nil {
-		return fmt.Errorf("ERROR: couldn't create kubeconfig.yaml in %s\n%+v", clusterDir, err)
-	}
-	defer kubeconfigfile.Close()
+	// output kubeconfig file path to stdout
+	fmt.Println(kubeConfigPath)
+	return nil
+}
 
-	// write to file, skipping the first 512 bytes which contain file metadata and trimming any NULL characters
-	_, err = kubeconfigfile.Write(bytes.Trim(readBytes[512:], "\x00"))
-	if err != nil {
-		return fmt.Errorf("ERROR: couldn't write to kubeconfig.yaml\n%+v", err)
+func Shell(c *cli.Context) error {
+	if c.String("shell") != "bash" {
+		return fmt.Errorf("%s is not supported. Only bash is supported", c.String("shell"))
 	}
 
-	// output kubeconfig file path to stdout
-	fmt.Println(destPath)
-
-	return nil
+	return bashShell(c.String("name"), c.String("command"))
 }

cli/shell.go

@@ -0,0 +1,51 @@
+package run
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+)
+
+func bashShell(cluster string, command string) error {
+	kubeConfigPath, err := getKubeConfig(cluster)
+	if err != nil {
+		return err
+	}
+
+	subShell := os.ExpandEnv("$__K3D_CLUSTER__")
+	if len(subShell) > 0 {
+		return fmt.Errorf("Error: Already in subshell of cluster %s", subShell)
+	}
+
+	bashPath, err := exec.LookPath("bash")
+	if err != nil {
+		return err
+	}
+
+	cmd := exec.Command(bashPath, "--noprofile", "--norc")
+
+	if len(command) > 0 {
+		cmd.Args = append(cmd.Args, "-c", command)
+
+	}
+
+	// Set up stdio
+	cmd.Stdout = os.Stdout
+	cmd.Stdin = os.Stdin
+	cmd.Stderr = os.Stderr
+
+	// Set up Promot
+	setPS1 := fmt.Sprintf("PS1=[%s}%s", cluster, os.Getenv("PS1"))
+
+	// Set up KUBECONFIG
+	setKube := fmt.Sprintf("KUBECONFIG=%s", kubeConfigPath)
+
+	// Declare subshell
+	subShell = fmt.Sprintf("__K3D_CLUSTER__=%s", cluster)
+
+	newEnv := append(os.Environ(), setPS1, setKube, subShell)
+
+	cmd.Env = newEnv
+
+	return cmd.Run()
+}

main.go

@@ -45,6 +45,28 @@ func main() {
 			Usage:   "Check if docker is running",
 			Action:  run.CheckTools,
 		},
+		{
+			// shell starts a shell in the context of a running cluster
+			Name:  "shell",
+			Usage: "Start a subshell for a cluster",
+			Flags: []cli.Flag{
+				cli.StringFlag{
+					Name:  "name, n",
+					Value: defaultK3sClusterName,
+					Usage: "Set a name for the cluster",
+				},
+				cli.StringFlag{
+					Name:  "command, c",
+					Usage: "Run a shell command in the context of the cluster",
+				},
+				cli.StringFlag{
+					Name:  "shell, s",
+					Value: "bash",
+					Usage: "Sub shell type. Only bash is supported. (default bash)",
+				},
+			},
+			Action: run.Shell,
+		},
 		{
 			// create creates a new k3s cluster in docker containers
 			Name:    "create",