UPSTREAM: 96120: kubelet: Expose a simple Get-WinEvent shim on the ku…

…belet logs endpoint

Provide an administrator a streaming view of event logs on Windows
machines without them having to implement a client side reader.

The kubelet API for querying the Linux journal is re-used for invoking
the Get-WinEvent cmdlet in a PowerShell.
Parameters that have no functional equivalence in Get-WinEvent are
ignored when assembling the command.

Only available to cluster admins.

openshift-rebase(v1.24):source=6a457760045

pkg/kubelet/kubelet_server_journal.go

@@ -112,36 +112,6 @@ func newJournalArgsFromURL(query url.Values) (*journalArgs, error) {
 	}, nil
 }
 
-// Args returns the journalctl arguments for the given args.
-func (a *journalArgs) Args() []string {
-	args := []string{
-		"--utc",
-		"--no-pager",
-	}
-	if len(a.Since) > 0 {
-		args = append(args, "--since="+a.Since)
-	}
-	if len(a.Until) > 0 {
-		args = append(args, "--until="+a.Until)
-	}
-	if a.Tail > 0 {
-		args = append(args, "--pager-end", fmt.Sprintf("--lines=%d", a.Tail))
-	}
-	if len(a.Format) > 0 {
-		args = append(args, "--output="+a.Format)
-	}
-	for _, unit := range a.Units {
-		if len(unit) > 0 {
-			args = append(args, "--unit="+unit)
-		}
-	}
-	if len(a.Pattern) > 0 {
-		args = append(args, "--grep="+a.Pattern)
-		args = append(args, fmt.Sprintf("--case-sensitive=%t", a.CaseSensitive))
-	}
-	return args
-}
-
 // Copy streams the contents of the journalctl command executed with the current
 // args to the provided writer, timing out at a.Timeout. If an error occurs a line
 // is written to the output.
@@ -166,9 +136,8 @@ func (a *journalArgs) copyForBoot(ctx context.Context, w io.Writer, previousBoot
 		return
 	}
 
-	args := a.Args()
-	args = append(args, "--boot", fmt.Sprintf("%d", previousBoot))
-	cmd := exec.Command("journalctl", args...)
+	cmdStr, args := getLoggingCmd(a, previousBoot)
+	cmd := exec.Command(cmdStr, args...)
 	cmd.Stdout = w
 	cmd.Stderr = w
 

pkg/kubelet/kubelet_server_journal_linux.go

@@ -0,0 +1,40 @@
+// +build linux
+
+package kubelet
+
+import (
+	"fmt"
+)
+
+// getLoggingCmd returns the journalctl cmd and arguments for the given journalArgs and boot
+func getLoggingCmd(a *journalArgs, boot int) (string, []string) {
+	args := []string{
+		"--utc",
+		"--no-pager",
+	}
+	if len(a.Since) > 0 {
+		args = append(args, "--since="+a.Since)
+	}
+	if len(a.Until) > 0 {
+		args = append(args, "--until="+a.Until)
+	}
+	if a.Tail > 0 {
+		args = append(args, "--pager-end", fmt.Sprintf("--lines=%d", a.Tail))
+	}
+	if len(a.Format) > 0 {
+		args = append(args, "--output="+a.Format)
+	}
+	for _, unit := range a.Units {
+		if len(unit) > 0 {
+			args = append(args, "--unit="+unit)
+		}
+	}
+	if len(a.Pattern) > 0 {
+		args = append(args, "--grep="+a.Pattern)
+		args = append(args, fmt.Sprintf("--case-sensitive=%t", a.CaseSensitive))
+	}
+
+	args = append(args, "--boot", fmt.Sprintf("%d", boot))
+
+	return "journalctl", args
+}

pkg/kubelet/kubelet_server_journal_others.go

@@ -0,0 +1,8 @@
+// +build !linux,!windows
+
+package kubelet
+
+// getLoggingCmd on unsupported operating systems returns the echo command and a warning message (as strings)
+func getLoggingCmd(a *journalArgs, boot int) (string, []string) {
+	return "echo", []string{"Operating System Not Supported"}
+}

pkg/kubelet/kubelet_server_journal_test.go

@@ -3,6 +3,7 @@ package kubelet
 import (
 	"net/url"
 	"reflect"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -11,16 +12,35 @@ import (
 
 func Test_journalArgs_Args(t *testing.T) {
 	tests := []struct {
-		name string
-		args journalArgs
-		want []string
+		name        string
+		args        journalArgs
+		wantLinux   []string
+		wantWindows []string
+		wantOtherOS []string
 	}{
-		{args: journalArgs{}, want: []string{"--utc", "--no-pager"}},
+		{
+			args:        journalArgs{},
+			wantLinux:   []string{"--utc", "--no-pager", "--boot", "0"},
+			wantWindows: []string{"-NonInteractive", "-ExecutionPolicy", "Bypass", "-Command", "Get-WinEvent -FilterHashtable @{LogName='Application'} | Sort-Object TimeCreated | Format-Table -AutoSize -Wrap"},
+			wantOtherOS: []string{"Operating System Not Supported"},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := tt.args.Args(); !reflect.DeepEqual(got, tt.want) {
-				t.Errorf("journalArgs.Args() = %v, want %v", got, tt.want)
+			_, got := getLoggingCmd(&tt.args, 0)
+			switch os := runtime.GOOS; os {
+			case "linux":
+				if !reflect.DeepEqual(got, tt.wantLinux) {
+					t.Errorf("getLoggingCmd(journalArgs{}, 0) = %v, want %v", got, tt.wantLinux)
+				}
+			case "windows":
+				if !reflect.DeepEqual(got, tt.wantWindows) {
+					t.Errorf("getLoggingCmd(journalArgs{}, 0) = %v, want %v", got, tt.wantWindows)
+				}
+			default:
+				if !reflect.DeepEqual(got, tt.wantOtherOS) {
+					t.Errorf("getLoggingCmd(journalArgs{}, 0) = %v, want %v", got, tt.wantWindows)
+				}
 			}
 		})
 	}

pkg/kubelet/kubelet_server_journal_windows.go

@@ -0,0 +1,53 @@
+// +build windows
+
+package kubelet
+
+import (
+	"fmt"
+	"strings"
+)
+
+// getLoggingCmd returns the powershell cmd and arguments for the given journalArgs and boot
+func getLoggingCmd(a *journalArgs, boot int) (string, []string) {
+	// The WinEvent log does not support querying by boot
+	// Set the cmd to return true on windows in case boot is not 0
+	if boot != 0 {
+		return "cd.", []string{}
+	}
+
+	args := []string{
+		"-NonInteractive",
+		"-ExecutionPolicy", "Bypass",
+		"-Command",
+	}
+
+	psCmd := "Get-WinEvent -FilterHashtable @{LogName='Application'"
+	if len(a.Since) > 0 {
+		psCmd += fmt.Sprintf("; StartTime='%s'", a.Since)
+	}
+	if len(a.Until) > 0 {
+		psCmd += fmt.Sprintf("; EndTime='%s'", a.Until)
+	}
+	var units []string
+	for _, unit := range a.Units {
+		if len(unit) > 0 {
+			units = append(units, "'"+unit+"'")
+		}
+	}
+	if len(units) > 0 {
+		psCmd += fmt.Sprintf("; ProviderName=%s", strings.Join(units, ","))
+	}
+	psCmd += "}"
+	if a.Tail > 0 {
+		psCmd += fmt.Sprintf(" -MaxEvents %d", a.Tail)
+	}
+	psCmd += " | Sort-Object TimeCreated"
+	if len(a.Pattern) > 0 {
+		psCmd += fmt.Sprintf(" | Where-Object -Property Message -Match %s", a.Pattern)
+	}
+	psCmd += " | Format-Table -AutoSize -Wrap"
+
+	args = append(args, psCmd)
+
+	return "PowerShell.exe", args
+}