Files
gotenberg/pkg/modules/qpdf/qpdf.go

118 lines
2.8 KiB
Go

package qpdf
import (
"context"
"errors"
"fmt"
"os"
"sync"
"github.com/gotenberg/gotenberg/v7/pkg/gotenberg"
"go.uber.org/zap"
)
func init() {
gotenberg.MustRegisterModule(QPDF{})
}
// QPDF abstracts the CLI tool QPDF and implements the gotenberg.PDFEngine
// interface.
type QPDF struct {
binPath string
}
// Descriptor returns a QPDF's module descriptor.
func (QPDF) Descriptor() gotenberg.ModuleDescriptor {
return gotenberg.ModuleDescriptor{
ID: "qpdf",
New: func() gotenberg.Module { return new(QPDF) },
}
}
// Provision sets the modules properties. It returns an error if the
// environment variable QPDF_BIN_PATH is not set.
func (engine *QPDF) Provision(_ *gotenberg.Context) error {
binPath, ok := os.LookupEnv("QPDF_BIN_PATH")
if !ok {
return errors.New("QPDF_BIN_PATH environment variable is not set")
}
engine.binPath = binPath
return nil
}
// Validate validates the module properties.
func (engine QPDF) Validate() error {
_, err := os.Stat(engine.binPath)
if os.IsNotExist(err) {
return fmt.Errorf("QPDF binary path does not exist: %w", err)
}
return nil
}
// Metrics returns the metrics.
func (engine QPDF) Metrics() ([]gotenberg.Metric, error) {
return []gotenberg.Metric{
{
Name: "qpdf_active_instances_count",
Description: "Current number of active QPDF instances.",
Read: func() float64 {
activeInstancesCountMu.RLock()
defer activeInstancesCountMu.RUnlock()
return activeInstancesCount
},
},
}, nil
}
// Merge merges the given PDFs into a unique PDF.
func (engine QPDF) Merge(ctx context.Context, logger *zap.Logger, inputPaths []string, outputPath string) error {
var args []string
args = append(args, "--empty")
args = append(args, "--pages")
args = append(args, inputPaths...)
args = append(args, "--", outputPath)
cmd, err := gotenberg.CommandContext(ctx, logger, engine.binPath, args...)
if err != nil {
return fmt.Errorf("create command: %w", err)
}
activeInstancesCountMu.Lock()
activeInstancesCount += 1
activeInstancesCountMu.Unlock()
_, err = cmd.Exec()
activeInstancesCountMu.Lock()
activeInstancesCount -= 1
activeInstancesCountMu.Unlock()
if err == nil {
return nil
}
return fmt.Errorf("merge PDFs with QPDF: %w", err)
}
// Convert is not available for this PDF engine.
func (engine QPDF) Convert(_ context.Context, _ *zap.Logger, format, _, _ string) error {
return fmt.Errorf("convert PDF to '%s' with QPDF: %w", format, gotenberg.ErrPDFEngineMethodNotAvailable)
}
var (
activeInstancesCount float64
activeInstancesCountMu sync.RWMutex
)
var (
_ gotenberg.Module = (*QPDF)(nil)
_ gotenberg.Provisioner = (*QPDF)(nil)
_ gotenberg.Validator = (*QPDF)(nil)
_ gotenberg.MetricsProvider = (*QPDF)(nil)
_ gotenberg.PDFEngine = (*QPDF)(nil)
)