From 6f4090fcb3e5d3024096bdcc13e171a23e0b2f0c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pedro=20P=C3=A9rez?= <hola@pedroperez.dev>
Date: Thu, 30 Oct 2025 15:12:36 +0100
Subject: [PATCH] add backoff

---
 service_b/go.mod                            |  5 +++-
 service_b/go.sum                            |  2 ++
 service_b/internal/domains/meteo/service.go | 31 +++++++++++++++------
 3 files changed, 29 insertions(+), 9 deletions(-)
 create mode 100644 service_b/go.sum

diff --git a/service_b/go.mod b/service_b/go.mod
index 5fe644d..7cc9718 100644
--- a/service_b/go.mod
+++ b/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
+)
diff --git a/service_b/go.sum b/service_b/go.sum
new file mode 100644
index 0000000..a8cc689
--- /dev/null
+++ b/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=
diff --git a/service_b/internal/domains/meteo/service.go b/service_b/internal/domains/meteo/service.go
index 53df9ec..3d1e92a 100644
--- a/service_b/internal/domains/meteo/service.go
+++ b/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 {
@@ -29,19 +32,31 @@ func (s *Service) GetWeatherByCity(ctx context.Context, params GetMeteoData) ([]
 	}
 	toDate := fromDate.AddDate(0, 0, params.Days-1)
 
-	url := fmt.Sprintf("http://localhost:8080/data?city=%s&from=%s&to=%s",
-		params.Location, params.Date, toDate.Format("2006-01-02"))
+	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"))
 
-	resp, err := http.Get(url)
-	if err != nil {
-		return nil, err
+		resp, err := http.Get(url)
+		if err != nil {
+			return nil, err
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode == http.StatusBadRequest {
+			return nil, backoff.Permanent(errors.New("bad request"))
+		}
+
+		return resp, nil
 	}
-	defer resp.Body.Close()
 
-	// TODO add backoff
+	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
 }