feat: add 7.x source code

pkg/modules/pdfengines/multi.go

@@ -0,0 +1,81 @@
+package pdfengines
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
+	"go.uber.org/multierr"
+	"go.uber.org/zap"
+)
+
+// multiPDFEngines implements the gotenberg.PDFEngine interface and gathers one
+// or more gotenberg.PDFEngine. It provides a sort of fallback mechanism: if an
+// engine's method returns an error, it calls the same method from another
+// engine.
+type multiPDFEngines struct {
+	engines []gotenberg.PDFEngine
+}
+
+// newMultiPDFEngines returns a multiPDFEngines. Arguments' order determines the
+// order of the engines called.
+func newMultiPDFEngines(engines ...gotenberg.PDFEngine) *multiPDFEngines {
+	return &multiPDFEngines{
+		engines: engines,
+	}
+}
+
+// Merge tries to merge the given PDFs into a unique PDF thanks to its
+// children. If the context is done, it stops and returns an error.
+func (multi multiPDFEngines) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
+	var err error
+	errChan := make(chan error, 1)
+
+	for _, engine := range multi.engines {
+		go func(engine gotenberg.PDFEngine) {
+			errChan <- engine.Merge(ctx, logger, inputPaths, outputPath)
+		}(engine)
+
+		select {
+		case mergeErr := <-errChan:
+			errored := multierr.AppendInto(&err, mergeErr)
+			if !errored {
+				return nil
+			}
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+
+	return fmt.Errorf("merge PDFs with multi PDF engines: %w", err)
+}
+
+// Convert converts the given PDF to a specific PDF format. thanks to its
+// children. If the context is done, it stops and returns an error.
+func (multi multiPDFEngines) Convert(ctx context.Context, logger *zap.Logger, format, inputPath, outputPath string) error {
+	var err error
+	errChan := make(chan error, 1)
+
+	for _, engine := range multi.engines {
+		go func(engine gotenberg.PDFEngine) {
+			errChan <- engine.Convert(ctx, logger, format, inputPath, outputPath)
+		}(engine)
+
+		select {
+		case mergeErr := <-errChan:
+			errored := multierr.AppendInto(&err, mergeErr)
+			if !errored {
+				return nil
+			}
+		case <-ctx.Done():
+			return ctx.Err()
+		}
+	}
+
+	return fmt.Errorf("convert PDF to '%s' with multi PDF engines: %w", format, err)
+}
+
+// Interface guards.
+var (
+	_ gotenberg.PDFEngine = (*multiPDFEngines)(nil)
+)