fix(kubernetes): include structured key/value context in client-go logs (#8490)

plugin/kubernetes/logger_test.go

@@ -0,0 +1,136 @@
+package kubernetes
+
+import (
+	"bytes"
+	"errors"
+	golog "log"
+	"strings"
+	"testing"
+
+	clog "github.com/coredns/coredns/plugin/pkg/log"
+)
+
+func newTestLoggerAdapter(buf *bytes.Buffer) *loggerAdapter {
+	golog.SetOutput(buf)
+	return &loggerAdapter{P: clog.NewWithPlugin("kubernetes")}
+}
+
+func TestLoggerAdapterErrorIncludesKeysAndValues(t *testing.T) {
+	var buf bytes.Buffer
+	l := newTestLoggerAdapter(&buf)
+	defer clog.Discard()
+
+	err := errors.New(`Get "https://10.96.0.1:443/api/v1/services": i/o timeout`)
+	l.Error(err, "Failed to watch", "reflector", "reflector-x", "type", "*v1.Service")
+
+	got := buf.String()
+	for _, want := range []string{
+		"Failed to watch",
+		`Get "https://10.96.0.1:443/api/v1/services": i/o timeout`,
+		`reflector="reflector-x"`,
+		`type="*v1.Service"`,
+	} {
+		if !strings.Contains(got, want) {
+			t.Errorf("log output missing %q, got: %q", want, got)
+		}
+	}
+}
+
+func TestLoggerAdapterErrorNilError(t *testing.T) {
+	var buf bytes.Buffer
+	l := newTestLoggerAdapter(&buf)
+	defer clog.Discard()
+
+	l.Error(nil, "Unexpected watch event object", "reflector", "reflector-x")
+
+	got := buf.String()
+	if strings.Contains(got, "<nil>") {
+		t.Errorf("log output contains formatting artifact for nil error: %q", got)
+	}
+	for _, want := range []string{"Unexpected watch event object", `reflector="reflector-x"`} {
+		if !strings.Contains(got, want) {
+			t.Errorf("log output missing %q, got: %q", want, got)
+		}
+	}
+}
+
+func TestLoggerAdapterInfoIncludesKeysAndValues(t *testing.T) {
+	var buf bytes.Buffer
+	l := newTestLoggerAdapter(&buf)
+	defer clog.Discard()
+
+	err := errors.New("very short watch")
+	l.Info(0, "Warning: watch ended with error", "reflector", "reflector-x", "err", err)
+
+	got := buf.String()
+	for _, want := range []string{
+		"Warning: watch ended with error",
+		`reflector="reflector-x"`,
+		`err="very short watch"`,
+	} {
+		if !strings.Contains(got, want) {
+			t.Errorf("log output missing %q, got: %q", want, got)
+		}
+	}
+}
+
+func TestLoggerAdapterWithValues(t *testing.T) {
+	var buf bytes.Buffer
+	l := newTestLoggerAdapter(&buf)
+	defer clog.Discard()
+
+	sink := l.WithValues("reflector", "reflector-x")
+	sink.Error(errors.New("boom"), "Failed to watch")
+
+	got := buf.String()
+	for _, want := range []string{"Failed to watch", "boom", `reflector="reflector-x"`} {
+		if !strings.Contains(got, want) {
+			t.Errorf("log output missing %q, got: %q", want, got)
+		}
+	}
+
+	// WithValues must not mutate the parent sink.
+	buf.Reset()
+	l.Error(errors.New("boom"), "Failed to watch")
+	if strings.Contains(buf.String(), "reflector-x") {
+		t.Errorf("parent sink polluted by WithValues: %q", buf.String())
+	}
+}
+
+func TestLoggerAdapterWithValuesOddLength(t *testing.T) {
+	var buf bytes.Buffer
+	l := newTestLoggerAdapter(&buf)
+	defer clog.Discard()
+
+	// An odd-length WithValues list must be padded so that later
+	// key/value pairs stay aligned, matching klog behaviour.
+	sink := l.WithValues("base-key")
+	sink.Info(0, "msg", "call-key", "call-value")
+
+	got := buf.String()
+	if want := `base-key="(MISSING)" call-key="call-value"`; !strings.Contains(got, want) {
+		t.Errorf("log output missing %q, got: %q", want, got)
+	}
+	if strings.Contains(got, `base-key="call-key"`) {
+		t.Errorf("key/value pairs misaligned: %q", got)
+	}
+}
+
+func TestLoggerAdapterDuplicateKeysLastWins(t *testing.T) {
+	var buf bytes.Buffer
+	l := newTestLoggerAdapter(&buf)
+	defer clog.Discard()
+
+	sink := l.WithValues("reflector", "old", "type", "*v1.Service")
+	sink.Error(nil, "msg", "reflector", "new")
+
+	got := buf.String()
+	if strings.Count(got, "reflector=") != 1 {
+		t.Errorf("expected a single reflector key, got: %q", got)
+	}
+	for _, want := range []string{`reflector="new"`, `type="*v1.Service"`} {
+		if !strings.Contains(got, want) {
+			t.Errorf("log output missing %q, got: %q", want, got)
+		}
+	}
+}