Feature/exec streaming output

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
     - name: Install Go
       uses: actions/setup-go@v2
       with:
-        go-version: '^1.20.0'
+        go-version: '^1.21.0'
     - name: Run make check
       run: |
         export PATH=${PATH}:`go env GOPATH`/bin

VERSION

@@ -1 +1 @@
-v0.8.0
+v0.8.1

go.mod

@@ -36,6 +36,7 @@ require (
 	github.com/Masterminds/semver v1.5.0
 	github.com/becheran/wildmatch-go v1.0.0
 	github.com/gardener/gardener-extension-provider-openstack v1.24.2
+	github.com/go-cmd/cmd v1.4.2
 	github.com/google/addlicense v1.0.0
 	github.com/onsi/ginkgo/v2 v2.1.3
 	github.com/rancher/norman v0.0.0-20220621173721-cba80063e705

go.sum

@@ -377,6 +377,8 @@ github.com/ghodss/yaml v1.0.0/go.mod h1:4dBDuWmgqj2HViK6kFavaiC9ZROes6MMH2rRYeME
 github.com/gliderlabs/ssh v0.2.2/go.mod h1:U7qILu1NlMHj9FlMhZLlkCdDnU1DBEAqr0aevW3Awn0=
 github.com/globalsign/mgo v0.0.0-20180905125535-1ca0a4f7cbcb/go.mod h1:xkRDCp4j0OGD1HRkm4kmhM+pmpv3AKq5SU7GMg4oO/Q=
 github.com/globalsign/mgo v0.0.0-20181015135952-eeefdecb41b8/go.mod h1:xkRDCp4j0OGD1HRkm4kmhM+pmpv3AKq5SU7GMg4oO/Q=
+github.com/go-cmd/cmd v1.4.2 h1:pnX38iIJHh4huzBSqfkAZkfXrVwM/5EccAJmrVqMnbg=
+github.com/go-cmd/cmd v1.4.2/go.mod h1:u3hxg/ry+D5kwh8WvUkHLAMe2zQCaXd00t35WfQaOFk=
 github.com/go-errors/errors v1.0.1/go.mod h1:f4zRHt4oKfwPJE5k8C9vpYG+aDHdBFUsgrm6/TyX73Q=
 github.com/go-git/gcfg v1.5.0/go.mod h1:5m20vg6GwYabIxaOonVkTdrILxQMpEShl1xiMF4ua+E=
 github.com/go-git/go-billy/v5 v5.2.0/go.mod h1:pmpqyWchKfYfrkb/UVH4otLvyi/5gJlGI4Hb3ZqZ3W0=
@@ -460,7 +462,7 @@ github.com/go-openapi/validate v0.19.8/go.mod h1:8DJv2CVJQ6kGNpFW6eV9N3JviE1C85n
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-task/slim-sprig v0.0.0-20210107165309-348f09dbbbc0 h1:p104kn46Q8WdvHunIJ9dAyjPVtrBPhSr3KT2yUst43I=
 github.com/go-task/slim-sprig v0.0.0-20210107165309-348f09dbbbc0/go.mod h1:fyg7847qk6SyHyPtNmDHnmrv/HOrqktSC+C9fM+CJOE=
-github.com/go-test/deep v1.0.2 h1:onZX1rnHT3Wv6cqNgYyFOOlgVKJrksuCMCRvJStbMYw=
+github.com/go-test/deep v1.1.0 h1:WOcxcdHcvdgThNXjw0t76K42FXTU7HpNQWHpA2HHNlg=
 github.com/gobuffalo/envy v1.7.0/go.mod h1:n7DRkBerg/aorDM8kbduw5dN3oXGswK5liaSCx4T5NI=
 github.com/gobuffalo/flect v0.1.5/go.mod h1:W3K3X9ksuZfir8f/LrfVtWmCDQFfayuylOJ7sz/Fj80=
 github.com/gobuffalo/flect v0.2.0/go.mod h1:W3K3X9ksuZfir8f/LrfVtWmCDQFfayuylOJ7sz/Fj80=

pkg/subcommands/exec/exec.go

@@ -17,7 +17,8 @@ package exec
 import (
 	"fmt"
 	"os"
-	"os/exec"
+
+	"github.com/go-cmd/cmd"
 
 	"github.com/danielfoehrkn/kubeswitch/pkg/store"
 	list_contexts "github.com/danielfoehrkn/kubeswitch/pkg/subcommands/list-contexts"
@@ -37,26 +38,52 @@ func ExecuteCommand(pattern string, command []string, stores []store.KubeconfigS
 			return err
 		}
 		fmt.Printf("=== START Executing on %s ===\n", context)
-		cmd := exec.Command(command[0], command[1:]...)
+
+		// Disable output buffering, enable streaming
+		cmdOptions := cmd.Options{
+			Buffered:  false,
+			Streaming: true,
+		}
+
+		// Create Cmd with options
+		envCmd := cmd.NewCmdOptions(cmdOptions, command[0], command[1:]...)
 
 		// Set environment variables for the command
-		cmd.Env = os.Environ()
+		envCmd.Env = os.Environ()
 
 		kubeconfigEnvVar := fmt.Sprintf("KUBECONFIG=%s", *tmpKubeconfigFile)
-		cmd.Env = append(cmd.Env, kubeconfigEnvVar)
+		envCmd.Env = append(envCmd.Env, kubeconfigEnvVar)
 
-		// Redirect the command's output to the current process's output
-		cmd.Stdout = os.Stdout
-		cmd.Stderr = os.Stderr
+		// Print STDOUT and STDERR lines streaming from Cmd
+		doneChan := make(chan struct{})
+		go func() {
+			defer close(doneChan)
+			// Done when both channels have been closed
+			// https://dave.cheney.net/2013/04/30/curious-channels
+			for envCmd.Stdout != nil || envCmd.Stderr != nil {
+				select {
+				case line, open := <-envCmd.Stdout:
+					if !open {
+						envCmd.Stdout = nil
+						continue
+					}
+					fmt.Println(line)
+				case line, open := <-envCmd.Stderr:
+					if !open {
+						envCmd.Stderr = nil
+						continue
+					}
+					fmt.Fprintln(os.Stderr, line)
+				}
+			}
+		}()
 
-		cmd.Environ()
+		// Run and wait for Cmd to return, discard Status
+		<-envCmd.Start()
+
+		// Wait for goroutine to print everything
+		<-doneChan
 
-		// Run the command
-		err = cmd.Run()
-		if err != nil {
-			fmt.Printf("Command execution failed: %v\n", err)
-			return err
-		}
 		fmt.Printf("=== END Executing on %s ===\n", context)
 	}
 	return nil