process load balancing: broken but in progress

internal/pkg/print/office.go

@@ -0,0 +1,109 @@
+package print
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/thecodingmachine/gotenberg/internal/pkg/process"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/xerror"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/xexec"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/xlog"
+	"github.com/thecodingmachine/gotenberg/internal/pkg/xrand"
+)
+
+type officePrint struct {
+	logger xlog.Logger
+	fpaths []string
+	opts   OfficePrintOptions
+}
+
+// OfficePrintOptions helps customizing the
+// LibreOffice Print result.
+type OfficePrintOptions struct {
+	Landscape bool
+}
+
+// DefaultOfficePrinterOptions returns the default
+// LibreOffice Print options.
+func DefaultOfficePrinterOptions() OfficePrintOptions {
+	return OfficePrintOptions{
+		Landscape: false,
+	}
+}
+
+// NewOfficePrint returns a Print for
+// converting Office documents to PDF.
+func NewOfficePrint(logger xlog.Logger, fpaths []string, opts OfficePrintOptions) Print {
+	return officePrint{
+		logger: logger,
+		fpaths: fpaths,
+		opts:   opts,
+	}
+}
+
+func (p officePrint) Print(ctx context.Context, dest string, proc process.Process) error {
+	const op string = "print.officePrint.Print"
+	resolver := func() error {
+		fpaths := make([]string, len(p.fpaths))
+		dirPath := filepath.Dir(dest)
+		for i, fpath := range p.fpaths {
+			baseFilename := xrand.Get()
+			tmpDest := fmt.Sprintf("%s/%d%s.pdf", dirPath, i, baseFilename)
+			p.logger.DebugfOp(op, "converting '%s' to PDF...", fpath)
+			if err := unoconv(ctx, p.logger, fpath, tmpDest, p.opts); err != nil {
+				return err
+			}
+			p.logger.DebugfOp(op, "'%s.pdf' created", baseFilename)
+			fpaths[i] = tmpDest
+		}
+		if len(fpaths) == 1 {
+			p.logger.DebugOp(op, "only one PDF created, nothing to merge")
+			if err := os.Rename(fpaths[0], dest); err != nil {
+				return err
+			}
+			return nil
+		}
+		merger := NewMergePrint(p.logger, fpaths)
+		return merger.Print(ctx, dest, nil)
+	}
+	if err := resolver(); err != nil {
+		return xerror.New(op, err)
+	}
+	return nil
+}
+
+func unoconv(ctx context.Context, logger xlog.Logger, fpath, dest string, opts OfficePrintOptions) error {
+	const op string = "print.unoconv"
+	resolver := func() error {
+		args := []string{
+			"--format",
+			"pdf",
+		}
+		if opts.Landscape {
+			args = append(args, "--printer", "PaperOrientation=landscape")
+		}
+		args = append(args, "--output", dest, fpath)
+		cmd, err := xexec.CommandContext(
+			ctx,
+			logger,
+			"unoconv",
+			args...,
+		)
+		if err != nil {
+			return err
+		}
+		xexec.LogBeforeExecute(logger, cmd)
+		return cmd.Run()
+	}
+	if err := resolver(); err != nil {
+		return xerror.New(op, err)
+	}
+	return nil
+}
+
+// Compile-time checks to ensure type implements desired interfaces.
+var (
+	_ = Print(new(officePrint))
+)