fix: initialize prometheus text parsers

Author: kongfei605

inputs/node_exporter/collector/textfile.go

@@ -28,6 +28,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	dto "github.com/prometheus/client_model/go"
 	"github.com/prometheus/common/expfmt"
+	"github.com/prometheus/common/model"
 )
 
 var (
@@ -273,7 +274,7 @@ func (c *textFileCollector) processFile(dir, name string, ch chan<- prometheus.M
 	}
 	defer f.Close()
 
-	var parser expfmt.TextParser
+	parser := expfmt.NewTextParser(model.UTF8Validation)
 	families, err := parser.TextToMetricFamilies(f)
 	if err != nil {
 		return nil, nil, fmt.Errorf("failed to parse textfile data from %q: %w", path, err)

pkg/metrics/metrics.go

@@ -14,6 +14,7 @@ import (
 	"github.com/matttproud/golang_protobuf_extensions/pbutil"
 	dto "github.com/prometheus/client_model/go"
 	"github.com/prometheus/common/expfmt"
+	"github.com/prometheus/common/model"
 
 	"flashcat.cloud/categraf/pkg/prom"
 	"flashcat.cloud/categraf/types"
@@ -125,7 +126,7 @@ func Parse(buf []byte, header http.Header) (map[string]*dto.MetricFamily, error)
 }
 
 func ParseReader(r io.Reader, header http.Header) (map[string]*dto.MetricFamily, error) {
-	var parser expfmt.TextParser
+	parser := expfmt.NewTextParser(model.UTF8Validation)
 
 	reader := bufio.NewReader(r)
 

pkg/metrics/metrics_test.go

@@ -0,0 +1,28 @@
+package metrics
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+)
+
+func TestParseReaderTextFormatUsesValidationScheme(t *testing.T) {
+	input := strings.NewReader("# HELP sample_metric sample metric\n# TYPE sample_metric gauge\nsample_metric 1\n")
+
+	families, err := ParseReader(input, http.Header{})
+	if err != nil {
+		t.Fatalf("ParseReader returned error: %v", err)
+	}
+
+	if _, ok := families["sample_metric"]; !ok {
+		t.Fatalf("expected sample_metric family, got %v", families)
+	}
+}
+
+func TestParseReaderTextFormatRejectsInvalidUTF8MetricName(t *testing.T) {
+	input := strings.NewReader("sample_metric\xff 1\n")
+
+	if _, err := ParseReader(input, http.Header{}); err == nil {
+		t.Fatal("expected invalid UTF-8 metric name error")
+	}
+}