Add support for creating a reusable PS session.

powershell/powershell_test.go

@@ -114,3 +114,25 @@ func TestFile(t *testing.T) {
 		}
 	}
 }
+
+func TestNewSession(t *testing.T) {
+	ps, err := NewSession()
+	if err != nil {
+		t.Fatalf("NewSession() failed: %v", err)
+	}
+	if err := ps.Close(); err != nil {
+		t.Fatalf("Close() failed: %v", err)
+	}
+}
+
+func TestExecute(t *testing.T) {
+	ps, err := NewSession()
+	if err != nil {
+		t.Fatalf("NewSession() failed: %v", err)
+	}
+	defer ps.Close()
+	_, err = ps.Execute("ipconfig")
+	if err != nil {
+		t.Fatalf("Execute() failed: %v", err)
+	}
+}

powershell/powershell_windows.go

@@ -18,11 +18,15 @@
 package powershell
 
 import (
+	"bufio"
 	"encoding/json"
 	"fmt"
+	"io"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
+	"sync"
 )
 
 var (
@@ -106,3 +110,69 @@ func Version() (VersionTable, error) {
 	err = json.Unmarshal(o, &psv)
 	return psv, err
 }
+
+// Session manages a persistent PowerShell process.
+type Session struct {
+	cmd    *exec.Cmd
+	stdin  io.WriteCloser
+	stdout *bufio.Reader
+	mu     sync.Mutex
+}
+
+// NewSession creates and starts a new PowerShell session.
+func NewSession() (*Session, error) {
+	cmd := exec.Command(powerShellExe, "-NoExit", "-NoProfile", "-Command", "-")
+	stdin, err := cmd.StdinPipe()
+	if err != nil {
+		return nil, fmt.Errorf("failed to open stdin pipe: %w", err)
+	}
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return nil, fmt.Errorf("failed to open stdout pipe: %w", err)
+	}
+	cmd.Stderr = cmd.Stdout
+
+	if err := cmd.Start(); err != nil {
+		return nil, fmt.Errorf("failed to start PowerShell session: %w", err)
+	}
+	return &Session{
+		cmd:    cmd,
+		stdin:  stdin,
+		stdout: bufio.NewReader(stdout),
+	}, nil
+}
+
+// Execute runs a command in the PowerShell session and returns its output.
+func (ps *Session) Execute(command string) (string, error) {
+	ps.mu.Lock()
+	defer ps.mu.Unlock()
+
+	// This is annoying but we need some way of identifying the end of the command's output.
+	const endMarker = "----------END-OF-COMMAND-OUTPUT----------"
+	fullCommand := fmt.Sprintf("%s; Write-Host '%s'\n", command, endMarker)
+	if _, err := ps.stdin.Write([]byte(fullCommand)); err != nil {
+		return "", fmt.Errorf("failed to write to stdin: %w", err)
+	}
+
+	var output strings.Builder
+	for {
+		line, err := ps.stdout.ReadString('\n')
+		if err != nil {
+			return "", fmt.Errorf("failed to read from stdout: %w", err)
+		}
+		if strings.TrimSpace(line) == endMarker {
+			break
+		}
+		output.WriteString(line)
+	}
+	return strings.TrimSpace(output.String()), nil
+}
+
+// Close terminates the PowerShell session.
+func (ps *Session) Close() error {
+	// Attempt to close the stdin pipe first.
+	if err := ps.stdin.Close(); err != nil {
+		return fmt.Errorf("failed to close stdin: %w", err)
+	}
+	return ps.cmd.Process.Kill()
+}