feat(thumb): generator settings and test button

pkg/thumb/tester.go

@@ -0,0 +1,74 @@
+package thumb
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+)
+
+var (
+	ErrUnknownGenerator = errors.New("unknown generator type")
+	ErrUnknownOutput    = errors.New("unknown output from generator")
+)
+
+// TestGenerator tests thumb generator by getting lib version
+func TestGenerator(ctx context.Context, name, executable string) (string, error) {
+	switch name {
+	case "vips":
+		return testVipsGenerator(ctx, executable)
+	case "ffmpeg":
+		return testFfmpegGenerator(ctx, executable)
+	case "libreOffice":
+		return testLibreOfficeGenerator(ctx, executable)
+	default:
+		return "", ErrUnknownGenerator
+	}
+}
+
+func testVipsGenerator(ctx context.Context, executable string) (string, error) {
+	cmd := exec.CommandContext(ctx, executable, "--version")
+	var output bytes.Buffer
+	cmd.Stdout = &output
+	if err := cmd.Run(); err != nil {
+		return "", fmt.Errorf("failed to invoke vips executable: %w", err)
+	}
+
+	if !strings.Contains(output.String(), "vips") {
+		return "", ErrUnknownOutput
+	}
+
+	return output.String(), nil
+}
+
+func testFfmpegGenerator(ctx context.Context, executable string) (string, error) {
+	cmd := exec.CommandContext(ctx, executable, "-version")
+	var output bytes.Buffer
+	cmd.Stdout = &output
+	if err := cmd.Run(); err != nil {
+		return "", fmt.Errorf("failed to invoke ffmpeg executable: %w", err)
+	}
+
+	if !strings.Contains(output.String(), "ffmpeg") {
+		return "", ErrUnknownOutput
+	}
+
+	return output.String(), nil
+}
+
+func testLibreOfficeGenerator(ctx context.Context, executable string) (string, error) {
+	cmd := exec.CommandContext(ctx, executable, "--version")
+	var output bytes.Buffer
+	cmd.Stdout = &output
+	if err := cmd.Run(); err != nil {
+		return "", fmt.Errorf("failed to invoke libreoffice executable: %w", err)
+	}
+
+	if !strings.Contains(output.String(), "LibreOffice") {
+		return "", ErrUnknownOutput
+	}
+
+	return output.String(), nil
+}