Merge pull request #1273 from r2d4/logs

Add -f --folow option to minikube logs

cmd/minikube/cmd/logs.go

@@ -27,6 +27,10 @@ import (
 	"k8s.io/minikube/pkg/minikube/machine"
 )
 
+var (
+	follow bool
+)
+
 // logsCmd represents the logs command
 var logsCmd = &cobra.Command{
 	Use:   "logs",
@@ -39,7 +43,7 @@ var logsCmd = &cobra.Command{
 			os.Exit(1)
 		}
 		defer api.Close()
-		s, err := cluster.GetHostLogs(api)
+		s, err := cluster.GetHostLogs(api, follow)
 		if err != nil {
 			log.Println("Error getting machine logs:", err)
 			cmdUtil.MaybeReportErrorAndExit(err)
@@ -49,5 +53,6 @@ var logsCmd = &cobra.Command{
 }
 
 func init() {
+	logsCmd.Flags().BoolVarP(&follow, "follow", "f", false, "Show only the most recent journal entries, and continuously print new entries as they are appended to the journal.")
 	RootCmd.AddCommand(logsCmd)
 }

docs/bash-completion

@@ -706,6 +706,9 @@ _minikube_logs()
     flags_with_completion=()
     flags_completion=()
 
+    flags+=("--follow")
+    flags+=("-f")
+    local_nonpersistent_flags+=("--follow")
     flags+=("--alsologtostderr")
     flags+=("--log_backtrace_at=")
     flags+=("--log_dir=")

docs/minikube_logs.md

@@ -11,6 +11,12 @@ Gets the logs of the running localkube instance, used for debugging minikube, no
 minikube logs
 ```
 
+### Options
+
+```
+  -f, --follow   Show only the most recent journal entries, and continuously print new entries as they are appended to the journal.
+```
+
 ### Options inherited from parent commands
 
 ```

pkg/minikube/cluster/cluster.go

@@ -370,11 +370,27 @@ func GetHostDockerEnv(api libmachine.API) (map[string]string, error) {
 }
 
 // GetHostLogs gets the localkube logs of the host VM.
-func GetHostLogs(api libmachine.API) (string, error) {
+// If follow is specified, it will tail the logs
+func GetHostLogs(api libmachine.API, follow bool) (string, error) {
 	h, err := CheckIfApiExistsAndLoad(api)
 	if err != nil {
 		return "", errors.Wrap(err, "Error checking that api exists and loading it")
 	}
+	logsCommand, err := GetLogsCommand(follow)
+	if err != nil {
+		return "", errors.Wrap(err, "Error getting logs command")
+	}
+	if follow {
+		c, err := h.CreateSSHClient()
+		if err != nil {
+			return "", errors.Wrap(err, "Error creating ssh client")
+		}
+		err = c.Shell(logsCommand)
+		if err != nil {
+			return "", errors.Wrap(err, "error ssh shell")
+		}
+		return "", err
+	}
 	s, err := h.RunSSHCommand(logsCommand)
 	if err != nil {
 		return "", err

pkg/minikube/cluster/cluster_test.go

@@ -495,12 +495,34 @@ func TestHostGetLogs(t *testing.T) {
 	}
 	api.Hosts[constants.MachineName] = &host.Host{Driver: d}
 
-	if _, err := GetHostLogs(api); err != nil {
-		t.Fatalf("Error getting host logs: %s", err)
+	tests := []struct {
+		description string
+		follow      bool
+	}{
+		{
+			description: "logs",
+			follow:      false,
+		},
+		{
+			description: "logs -f",
+			follow:      true,
+		},
 	}
 
-	if _, ok := s.Commands[logsCommand]; !ok {
-		t.Fatalf("Expected command not run: %s", logsCommand)
+	for _, test := range tests {
+		t.Run(test.description, func(t *testing.T) {
+			t.Parallel()
+			cmd, err := GetLogsCommand(test.follow)
+			if err != nil {
+				t.Errorf("Error getting the logs command: %s", err)
+			}
+			if _, err = GetHostLogs(api, test.follow); err != nil {
+				t.Errorf("Error getting host logs: %s", err)
+			}
+			if _, ok := s.Commands[cmd]; !ok {
+				t.Errorf("Expected command to run but did not: %s", cmd)
+			}
+		})
 	}
 }
 

pkg/minikube/cluster/commands.go

@@ -180,13 +180,39 @@ func GenLocalkubeStartCmd(kubernetesConfig KubernetesConfig) (string, error) {
 	return buf.String(), nil
 }
 
-var logsCommand = fmt.Sprintf(`
+const logsTemplate = `
 if which systemctl 2>&1 1>/dev/null; then
-  sudo journalctl -u localkube
+  sudo journalctl {{.Flags}} -u localkube
 else
-  tail -n +1 %s %s
+  tail -n +1 {{.Flags}} {{.RemoteLocalkubeErrPath}} {{.RemoteLocalkubeOutPath}} %s
 fi
-`, constants.RemoteLocalKubeErrPath, constants.RemoteLocalKubeOutPath)
+`
+
+func GetLogsCommand(follow bool) (string, error) {
+	t, err := template.New("logsTemplate").Parse(logsTemplate)
+	if err != nil {
+		return "", err
+	}
+	var flags []string
+	if follow {
+		flags = append(flags, "-f")
+	}
+
+	buf := bytes.Buffer{}
+	data := struct {
+		RemoteLocalkubeErrPath string
+		RemoteLocalkubeOutPath string
+		Flags                  string
+	}{
+		RemoteLocalkubeErrPath: constants.RemoteLocalKubeErrPath,
+		RemoteLocalkubeOutPath: constants.RemoteLocalKubeOutPath,
+		Flags: strings.Join(flags, " "),
+	}
+	if err := t.Execute(&buf, data); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
 
 var localkubeStatusCommand = fmt.Sprintf(`
 if which systemctl 2>&1 1>/dev/null; then