fix(otelbench): wait for receiver readiness

cmd/otelbench/otel_log_bench.go

@@ -8,6 +8,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/cenkalti/backoff/v4"
 	"github.com/go-faster/errors"
 	"github.com/go-faster/sdk/zctx"
 	"github.com/spf13/cobra"
@@ -173,9 +174,9 @@ func (b *LogsBench) generateBatch(r *rand.Rand, now time.Time) (logs plog.Logs,
 	return logs, lines, bytes
 }
 
-func (b *LogsBench) prepareTargets(args []string) error {
+func (b *LogsBench) prepareTargets(ctx context.Context, args []string) error {
 	for _, arg := range args {
-		client, err := b.prepareTarget(arg)
+		client, err := b.prepareTarget(ctx, arg)
 		if err != nil {
 			return errors.Wrapf(err, "prepare %q", arg)
 		}
@@ -190,14 +191,45 @@ func (b *LogsBench) prepareTargets(args []string) error {
 	return nil
 }
 
-func (b *LogsBench) prepareTarget(target string) (plogotlp.GRPCClient, error) {
+func (b *LogsBench) prepareTarget(ctx context.Context, target string) (plogotlp.GRPCClient, error) {
 	conn, err := grpc.NewClient(target,
 		grpc.WithTransportCredentials(insecure.NewCredentials()),
 	)
 	if err != nil {
-		return nil, errors.Wrap(err, "dial otlp")
+		return nil, errors.Wrap(err, "new client")
 	}
 	client := plogotlp.NewGRPCClient(conn)
+
+	var (
+		log = zctx.From(ctx).With(zap.String("target", target))
+		eb  = backoff.NewExponentialBackOff(
+			backoff.WithInitialInterval(5*time.Second),
+			backoff.WithMaxElapsedTime(time.Minute),
+		)
+	)
+	log.Info("Waiting for receiver")
+	if err := backoff.RetryNotify(
+		func() error {
+			_, err := client.Export(ctx, plogotlp.NewExportRequest())
+			if err != nil {
+				if cerr := ctx.Err(); cerr != nil {
+					return backoff.Permanent(cerr)
+				}
+				return err
+			}
+			return nil
+		},
+		eb,
+		func(err error, d time.Duration) {
+			log.Debug("Retry ping request",
+				zap.Error(err),
+			)
+		},
+	); err != nil {
+		return nil, err
+	}
+	log.Info("Receiver is ready")
+
 	return client, nil
 }
 
@@ -219,7 +251,7 @@ func newOtelLogsBenchCommand() *cobra.Command {
 			}()
 			ctx = zctx.Base(ctx, log)
 
-			if err := b.prepareTargets(args); err != nil {
+			if err := b.prepareTargets(ctx, args); err != nil {
 				return err
 			}
 			return b.Run(ctx)