feat(api): add debug route

pkg/modules/pdftk/pdftk.go

@@ -1,11 +1,14 @@
 package pdftk
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
+	"syscall"
 
 	"go.uber.org/zap"
 
@@ -52,6 +55,29 @@ func (engine *PdfTk) Validate() error {
 	return nil
 }
 
+// Debug returns additional debug data.
+func (engine *PdfTk) Debug() map[string]interface{} {
+	debug := make(map[string]interface{})
+
+	cmd := exec.Command(engine.binPath, "--version") //nolint:gosec
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+
+	output, err := cmd.Output()
+	if err != nil {
+		debug["version"] = err.Error()
+		return debug
+	}
+
+	lines := bytes.SplitN(output, []byte("\n"), 2)
+	if len(lines) > 0 {
+		debug["version"] = string(lines[0])
+	} else {
+		debug["version"] = "Unable to determine PDFtk version"
+	}
+
+	return debug
+}
+
 // Split splits a given PDF file.
 func (engine *PdfTk) Split(ctx context.Context, logger *zap.Logger, mode gotenberg.SplitMode, inputPath, outputDirPath string) ([]string, error) {
 	var args []string
@@ -124,5 +150,6 @@ var (
 	_ gotenberg.Module      = (*PdfTk)(nil)
 	_ gotenberg.Provisioner = (*PdfTk)(nil)
 	_ gotenberg.Validator   = (*PdfTk)(nil)
+	_ gotenberg.Debuggable  = (*PdfTk)(nil)
 	_ gotenberg.PdfEngine   = (*PdfTk)(nil)
 )

pkg/modules/pdftk/pdftk_test.go

@@ -71,6 +71,50 @@ func TestPdfTk_Validate(t *testing.T) {
 	}
 }
 
+func TestPdfTk_Debug(t *testing.T) {
+	for _, tc := range []struct {
+		scenario    string
+		engine      *PdfTk
+		expect      map[string]interface{}
+		doNotExpect map[string]interface{}
+	}{
+		{
+			scenario: "cannot determine version",
+			engine: &PdfTk{
+				binPath: "foo",
+			},
+			expect: map[string]interface{}{
+				"version": `exec: "foo": executable file not found in $PATH`,
+			},
+		},
+		{
+			scenario: "success",
+			engine: &PdfTk{
+				binPath: "echo",
+			},
+			doNotExpect: map[string]interface{}{
+				"version": `exec: "echo": executable file not found in $PATH`,
+			},
+		},
+	} {
+		t.Run(tc.scenario, func(t *testing.T) {
+			d := tc.engine.Debug()
+
+			if tc.expect != nil {
+				if !reflect.DeepEqual(d, tc.expect) {
+					t.Errorf("expected '%v' but got '%v'", tc.expect, d)
+				}
+			}
+
+			if tc.doNotExpect != nil {
+				if reflect.DeepEqual(d, tc.doNotExpect) {
+					t.Errorf("did not expect '%v'", d)
+				}
+			}
+		})
+	}
+}
+
 func TestPdfTk_Merge(t *testing.T) {
 	for _, tc := range []struct {
 		scenario    string