feat(telemetry): record backing-binary versions on spans, captured at build time

pkg/modules/qpdf/version_test.go

@@ -0,0 +1,58 @@
+package qpdf
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/gotenberg/gotenberg/v8/pkg/gotenberg"
+)
+
+func TestQPdfDetectVersion(t *testing.T) {
+	t.Run("prefers the build-time version without executing qpdf", func(t *testing.T) {
+		dir := t.TempDir()
+		if err := os.WriteFile(filepath.Join(dir, "qpdf"), []byte("qpdf version 11.9.0\n"), 0o600); err != nil {
+			t.Fatalf("write version file: %v", err)
+		}
+		t.Setenv(gotenberg.BuildVersionsDirPathEnvVar, dir)
+
+		// A bogus binPath would error if executed, so a correct result proves
+		// the build-time file is used instead of running qpdf.
+		engine := &QPdf{binPath: "/nonexistent/qpdf"}
+		if got := engine.Debug()["version"]; got != "qpdf version 11.9.0" {
+			t.Errorf("Debug()[version] = %v, want the build-time value", got)
+		}
+	})
+
+	t.Run("falls back to executing qpdf when no build-time version", func(t *testing.T) {
+		t.Setenv(gotenberg.BuildVersionsDirPathEnvVar, "")
+
+		// With no build-time file and a bogus binPath, the exec fallback runs
+		// and records its error rather than a build-time value.
+		engine := &QPdf{binPath: "/nonexistent/qpdf"}
+		if got := engine.Debug()["version"]; got == "qpdf version 11.9.0" {
+			t.Errorf("Debug()[version] = %v, expected the exec fallback", got)
+		}
+	})
+
+	t.Run("exposes the version as a span attribute", func(t *testing.T) {
+		dir := t.TempDir()
+		if err := os.WriteFile(filepath.Join(dir, "qpdf"), []byte("qpdf version 12.2.0"), 0o600); err != nil {
+			t.Fatalf("write version file: %v", err)
+		}
+		t.Setenv(gotenberg.BuildVersionsDirPathEnvVar, dir)
+
+		// spanAttrs is what gets handed to trace.WithAttributes, so its output
+		// is exactly what a span carries.
+		engine := &QPdf{binPath: "/nonexistent/qpdf"}
+		var got string
+		for _, attr := range engine.spanAttrs() {
+			if attr.Key == "gotenberg.qpdf.version" {
+				got = attr.Value.AsString()
+			}
+		}
+		if got != "qpdf version 12.2.0" {
+			t.Errorf("span attribute gotenberg.qpdf.version = %q, want the build-time value", got)
+		}
+	})
+}