retry, client: support to log after execing some times (#7895)

ref #7894

Signed-off-by: Cabinfever_B <cabinfeveroier@gmail.com>

Co-authored-by: ti-chi-bot[bot] <108142056+ti-chi-bot[bot]@users.noreply.github.com>

client/retry/backoff.go

@@ -16,15 +16,31 @@ package retry
 
 import (
 	"context"
+	"reflect"
+	"runtime"
+	"strings"
 	"time"
 
 	"github.com/pingcap/errors"
 	"github.com/pingcap/failpoint"
+	"github.com/pingcap/log"
 	"go.uber.org/multierr"
+	"go.uber.org/zap"
 )
 
 const maxRecordErrorCount = 20
 
+// Option is used to customize the backoffer.
+type Option func(*Backoffer)
+
+// withMinLogInterval sets the minimum log interval for retrying.
+// Because the retry interval may be not the factor of log interval, so this is the minimum interval.
+func withMinLogInterval(interval time.Duration) Option {
+	return func(bo *Backoffer) {
+		bo.logInterval = interval
+	}
+}
+
 // Backoffer is a backoff policy for retrying operations.
 type Backoffer struct {
 	// base defines the initial time interval to wait before each retry.
@@ -36,6 +52,10 @@ type Backoffer struct {
 	// retryableChecker is used to check if the error is retryable.
 	// By default, all errors are retryable.
 	retryableChecker func(err error) bool
+	// logInterval defines the log interval for retrying.
+	logInterval time.Duration
+	// nextLogTime is used to record the next log time.
+	nextLogTime time.Duration
 
 	attempt      int
 	next         time.Duration
@@ -50,10 +70,12 @@ func (bo *Backoffer) Exec(
 	defer bo.resetBackoff()
 	var (
 		allErrors error
+		err       error
 		after     *time.Timer
 	)
+	fnName := getFunctionName(fn)
 	for {
-		err := fn()
+		err = fn()
 		bo.attempt++
 		if bo.attempt < maxRecordErrorCount {
 			// multierr.Append will ignore nil error.
@@ -63,6 +85,13 @@ func (bo *Backoffer) Exec(
 			break
 		}
 		currentInterval := bo.nextInterval()
+		bo.nextLogTime += currentInterval
+		if err != nil {
+			if bo.logInterval > 0 && bo.nextLogTime >= bo.logInterval {
+				bo.nextLogTime %= bo.logInterval
+				log.Warn("call PD API failed and retrying", zap.String("api", fnName), zap.Int("retry-time", bo.attempt), zap.Error(err))
+			}
+		}
 		if after == nil {
 			after = time.NewTimer(currentInterval)
 		} else {
@@ -93,7 +122,7 @@ func (bo *Backoffer) Exec(
 //   - `base` defines the initial time interval to wait before each retry.
 //   - `max` defines the max time interval to wait before each retry.
 //   - `total` defines the max total time duration cost in retrying. If it's 0, it means infinite retry until success.
-func InitialBackoffer(base, max, total time.Duration) *Backoffer {
+func InitialBackoffer(base, max, total time.Duration, opts ...Option) *Backoffer {
 	// Make sure the base is less than or equal to the max.
 	if base > max {
 		base = max
@@ -102,7 +131,7 @@ func InitialBackoffer(base, max, total time.Duration) *Backoffer {
 	if total > 0 && total < base {
 		total = base
 	}
-	return &Backoffer{
+	bo := &Backoffer{
 		base:  base,
 		max:   max,
 		total: total,
@@ -113,6 +142,10 @@ func InitialBackoffer(base, max, total time.Duration) *Backoffer {
 		currentTotal: 0,
 		attempt:      0,
 	}
+	for _, opt := range opts {
+		opt(bo)
+	}
+	return bo
 }
 
 // SetRetryableChecker sets the retryable checker.
@@ -152,6 +185,7 @@ func (bo *Backoffer) resetBackoff() {
 	bo.next = bo.base
 	bo.currentTotal = 0
 	bo.attempt = 0
+	bo.nextLogTime = 0
 }
 
 // Only used for test.
@@ -161,3 +195,8 @@ var testBackOffExecuteFlag = false
 func TestBackOffExecute() bool {
 	return testBackOffExecuteFlag
 }
+
+func getFunctionName(f any) string {
+	strs := strings.Split(runtime.FuncForPC(reflect.ValueOf(f).Pointer()).Name(), ".")
+	return strings.Split(strs[len(strs)-1], "-")[0]
+}

client/retry/backoff_test.go

@@ -15,12 +15,15 @@
 package retry
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"testing"
 	"time"
 
+	"github.com/pingcap/log"
 	"github.com/stretchr/testify/require"
+	"go.uber.org/zap"
 )
 
 func TestBackoffer(t *testing.T) {
@@ -107,3 +110,95 @@ func TestBackoffer(t *testing.T) {
 func isBackofferReset(bo *Backoffer) bool {
 	return bo.next == bo.base && bo.currentTotal == 0
 }
+
+func TestBackofferWithLog(t *testing.T) {
+	re := require.New(t)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	conf := &log.Config{Level: "debug", File: log.FileLogConfig{}, DisableTimestamp: true}
+	lg := newZapTestLogger(conf)
+	log.ReplaceGlobals(lg.Logger, nil)
+
+	bo := InitialBackoffer(time.Millisecond*10, time.Millisecond*100, time.Millisecond*1000, withMinLogInterval(time.Millisecond*100))
+	err := bo.Exec(ctx, testFn)
+	re.ErrorIs(err, errTest)
+
+	ms := lg.Messages()
+	len1 := len(ms)
+	// 10 + 20 + 40 + 80(log) + 100(log) * 9 >= 1000, so log ten times.
+	re.Len(ms, 10)
+	// 10 + 20 + 40 + 80 + 100 * 9, 13 times retry.
+	rfc := `["call PD API failed and retrying"] [api=testFn] [retry-time=13] [error=test]`
+	re.Contains(ms[len(ms)-1], rfc)
+	// 10 + 20 + 40 + 80(log), 4 times retry.
+	rfc = `["call PD API failed and retrying"] [api=testFn] [retry-time=4] [error=test]`
+	re.Contains(ms[0], rfc)
+
+	bo.resetBackoff()
+	err = bo.Exec(ctx, testFn)
+	re.ErrorIs(err, errTest)
+
+	ms = lg.Messages()
+	re.Len(ms, 20)
+	rfc = `["call PD API failed and retrying"] [api=testFn] [retry-time=13] [error=test]`
+	re.Contains(ms[len(ms)-1], rfc)
+	rfc = `["call PD API failed and retrying"] [api=testFn] [retry-time=4] [error=test]`
+	re.Contains(ms[len1], rfc)
+}
+
+var errTest = errors.New("test")
+
+func testFn() error {
+	return errTest
+}
+
+// testingWriter is a WriteSyncer that writes the the messages.
+type testingWriter struct {
+	messages []string
+}
+
+func newTestingWriter() *testingWriter {
+	return &testingWriter{}
+}
+
+func (w *testingWriter) Write(p []byte) (n int, err error) {
+	n = len(p)
+	p = bytes.TrimRight(p, "\n")
+	m := string(p)
+	w.messages = append(w.messages, m)
+	return n, nil
+}
+func (w *testingWriter) Sync() error {
+	return nil
+}
+
+type verifyLogger struct {
+	*zap.Logger
+	w *testingWriter
+}
+
+func (logger *verifyLogger) Message() string {
+	if logger.w.messages == nil {
+		return ""
+	}
+	return logger.w.messages[len(logger.w.messages)-1]
+}
+
+func (logger *verifyLogger) Messages() []string {
+	if logger.w.messages == nil {
+		return nil
+	}
+	return logger.w.messages
+}
+
+func newZapTestLogger(cfg *log.Config, opts ...zap.Option) verifyLogger {
+	// TestingWriter is used to write to memory.
+	// Used in the verify logger.
+	writer := newTestingWriter()
+	lg, _, _ := log.InitLoggerWithWriteSyncer(cfg, writer, writer, opts...)
+	return verifyLogger{
+		Logger: lg,
+		w:      writer,
+	}
+}