add backoff

service_b/go.mod

@@ -4,4 +4,7 @@ go 1.25.2
 
 replace pkg => ../pkg
 
-require pkg v0.0.0-00010101000000-000000000000
+require (
+	github.com/cenkalti/backoff/v5 v5.0.3
+	pkg v0.0.0-00010101000000-000000000000
+)

service_b/go.sum

@@ -0,0 +1,2 @@
+github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
+github.com/cenkalti/backoff/v5 v5.0.3/go.mod h1:rkhZdG3JZukswDf7f0cwqPNk4K0sa+F97BxZthm/crw=

service_b/internal/domains/meteo/service.go

@@ -2,11 +2,14 @@ package meteo
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"log/slog"
 	"net/http"
 	"sync"
 	"time"
+
+	"github.com/cenkalti/backoff/v5"
 )
 
 type inMemory struct {
@@ -29,6 +32,7 @@ func (s *Service) GetWeatherByCity(ctx context.Context, params GetMeteoData) ([]
 	}
 	toDate := fromDate.AddDate(0, 0, params.Days-1)
 
+	operation := func() (*http.Response, error) {
 		url := fmt.Sprintf("http://localhost:8080/data?city=%s&from=%s&to=%s",
 			params.Location, params.Date, toDate.Format("2006-01-02"))
 
@@ -38,10 +42,21 @@ func (s *Service) GetWeatherByCity(ctx context.Context, params GetMeteoData) ([]
 		}
 		defer resp.Body.Close()
 
-	// TODO add backoff
+		if resp.StatusCode == http.StatusBadRequest {
+			return nil, backoff.Permanent(errors.New("bad request"))
+		}
+
+		return resp, nil
+	}
+
+	result, err := backoff.Retry(ctx, operation, backoff.WithBackOff(backoff.NewExponentialBackOff()))
+	if err != nil {
+		slog.Error("somethin happened")
+		return []MeteoData{}, err
+	}
 	// TODO add ristretto
 
-	slog.Info("fetched data", "data", resp)
+	slog.Info("fetched data", "data", result)
 
 	return []MeteoData{}, nil
 }