Merge pull request #10 from MikeMwita/indempontency-and-retries

Better Retries with Exponential Backoff and jitter

pkg/sms/sms_sender.go

@@ -3,6 +3,7 @@ package sms
 import (
 	"encoding/json"
 	"fmt"
+	"math/rand"
 	"net/http"
 	"net/url"
 	"strings"
@@ -143,17 +144,21 @@ func (s *SmsSender) SendSMS() (SmsSenderResponse, error) {
 
 	return smsSenderResponse, fmt.Errorf("status code: %d", res.StatusCode)
 }
-// Retry sends an SMS with exponential backoff
+
 func (s *SmsSender) RetrySendSMS(maxRetries int) (SmsSenderResponse, error) {
 	for retry := 0; retry < maxRetries; retry++ {
-			response, err := s.SendSMS()
-			if err == nil {
-					return response, nil
-			}
+		response, err := s.SendSMS()
+		if err == nil {
+			return response, nil
+		}
 
-			delay := time.Duration(1<<uint(retry)) * time.Second
-			time.Sleep(delay)
-	}
+		delay := time.Duration(1<<uint(retry)) * time.Second
 
+		// Add jitter (randomness) to the delay
+		jitter := time.Duration(rand.Intn(int(delay))) * time.Millisecond
+		waitTime := delay + jitter
+
+		time.Sleep(waitTime)
+	}
 	return SmsSenderResponse{}, fmt.Errorf("max retries reached")
-}
+}

pkg/sms/sms_sender_test.go

@@ -1,6 +1,7 @@
 package sms
 
 import (
+	"fmt"
 	"testing"
 )
 
@@ -30,3 +31,105 @@ func TestSendSMS(t *testing.T) {
 		t.Errorf("empty message received in response")
 	}
 }
+
+func (s *SmsSender) MockSendSMS() (SmsSenderResponse, error) {
+	// Todo: Implement mock behavior
+	return SmsSenderResponse{
+		SmsMessageData: SmsMessageData{
+			Message: "Mocked success message",
+			Recipients: []Recipient{
+				{
+					Key:         "mock-recipient-key",
+					Cost:        "0.05",
+					SmsKey:      "mock-sms-key",
+					MessageId:   "mock-message-id",
+					MessagePart: 1,
+					Number:      "+254745617596",
+					Status:      "Success",
+					StatusCode:  "200",
+				},
+			},
+		},
+	}, nil
+}
+
+func TestRetrySendSMS(t *testing.T) {
+	sender := SmsSender{
+		ApiKey:     "your-api-key",
+		ApiUser:    "your-api-user",
+		Recipients: []string{"+254745617596"},
+		Message:    "Hello, this is a test message.",
+		Sender:     "YourSenderID",
+	}
+
+	maxRetries := 5
+
+	sender.SendSMS = sender.MockSendSMS
+
+	response, err := sender.RetrySendSMS(maxRetries)
+
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+
+	if response.SmsMessageData.Message != "Mocked success message" {
+		t.Errorf("unexpected message received in response")
+	}
+}
+
+func TestRetrySendSMS_Success(t *testing.T) {
+	sender := SmsSender{
+		ApiKey:     "your-api-key",
+		ApiUser:    "your-api-user",
+		Recipients: []string{"+254745617596"},
+		Message:    "Hello, this is a test message.",
+		Sender:     "YourSenderID",
+	}
+
+	maxRetries := 5
+
+	retryCount := 0
+	sender.SendSMS = func() (SmsSenderResponse, error) {
+		if retryCount < 3 {
+			retryCount++
+			return SmsSenderResponse{}, fmt.Errorf("mocked error")
+		}
+		return SmsSenderResponse{
+			SmsMessageData: SmsMessageData{
+				Message: "Success!",
+			},
+		}, nil
+	}
+
+	response, err := sender.RetrySendSMS(maxRetries)
+
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+
+	if response.SmsMessageData.Message != "Success!" {
+		t.Errorf("unexpected message received in response")
+	}
+}
+
+func TestRetrySendSMS_Failure(t *testing.T) {
+	sender := SmsSender{
+		ApiKey:     "your-api-key",
+		ApiUser:    "your-api-user",
+		Recipients: []string{"+254745617596"},
+		Message:    "Hello, this is a test message.",
+		Sender:     "YourSenderID",
+	}
+
+	maxRetries := 3
+
+	sender.SendSMS = func() (SmsSenderResponse, error) {
+		return SmsSenderResponse{}, fmt.Errorf("mocked error")
+	}
+
+	_, err := sender.RetrySendSMS(maxRetries)
+
+	if err == nil {
+		t.Errorf("expected error, got nil")
+	}
+}