refactor: Simplify and modernize loops (#1522)

* refactor: Simplify loops

* refactor: Modernize loops using range over int

---------

Co-authored-by: TwiN <twin@linux.com>

config/config.go

@@ -6,6 +6,7 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"slices"
 	"sort"
 	"strings"
 	"time"
@@ -136,7 +137,7 @@ func (config *Config) GetUniqueExtraMetricLabels() []string {
 			continue
 		}
 		for label := range ep.ExtraLabels {
-			if contains(labels, label) {
+			if slices.Contains(labels, label) {
 				continue
 			}
 			labels = append(labels, label)

config/config_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"slices"
 	"testing"
 	"time"
 
@@ -2052,7 +2053,7 @@ func TestConfig_GetUniqueExtraMetricLabels(t *testing.T) {
 				t.Errorf("expected %d labels, got %d", len(tt.expected), len(labels))
 			}
 			for _, label := range tt.expected {
-				if !contains(labels, label) {
+				if !slices.Contains(labels, label) {
 					t.Errorf("expected label %s to be present", label)
 				}
 			}

config/endpoint/condition.go

@@ -216,7 +216,7 @@ func sanitizeAndResolveNumericalWithContext(list []string, result *Result, conte
 
 func prettifyNumericalParameters(parameters []string, resolvedParameters []int64, operator string) string {
 	resolvedStrings := make([]string, 2)
-	for i := 0; i < 2; i++ {
+	for i := range 2 {
 		// Check if the parameter is a certificate or domain expiration placeholder
 		if parameters[i] == CertificateExpirationPlaceholder || parameters[i] == DomainExpirationPlaceholder {
 			// Format as duration string (convert milliseconds back to duration)

config/endpoint/endpoint.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
 	"math/rand"
 	"net"
 	"net/http"
@@ -489,9 +490,7 @@ func (e *Endpoint) call(result *Result) {
 	} else if endpointType == TypeWS {
 		wsHeaders := map[string]string{}
 		if e.Headers != nil {
-			for k, v := range e.Headers {
-				wsHeaders[k] = v
-			}
+			maps.Copy(wsHeaders, e.Headers)
 		}
 		if !hasHeader(wsHeaders, UserAgentHeader) {
 			wsHeaders[UserAgentHeader] = GatusUserAgent

config/endpoint/result.go

@@ -1,6 +1,7 @@
 package endpoint
 
 import (
+	"slices"
 	"time"
 )
 
@@ -66,11 +67,7 @@ type Result struct {
 // AddError adds an error to the result's list of errors.
 // It also ensures that there are no duplicates.
 func (r *Result) AddError(error string) {
-	for _, resultError := range r.Errors {
-		if resultError == error {
-			// If the error already exists, don't add it
-			return
-		}
+	if !slices.Contains(r.Errors, error) {
+		r.Errors = append(r.Errors, error+"")
 	}
-	r.Errors = append(r.Errors, error+"")
 }

config/gontext/gontext_test.go

@@ -340,9 +340,9 @@ func TestGontext_ConcurrentAccess(t *testing.T) {
 	done := make(chan bool, 10)
 
 	// Start 5 goroutines that read values
-	for i := 0; i < 5; i++ {
+	for i := range 5 {
 		go func(id int) {
-			for j := 0; j < 100; j++ {
+			for range 100 {
 				_, err := ctx.Get("counter")
 				if err != nil {
 					t.Errorf("Reader %d error: %v", id, err)
@@ -353,9 +353,9 @@ func TestGontext_ConcurrentAccess(t *testing.T) {
 	}
 
 	// Start 5 goroutines that write values
-	for i := 0; i < 5; i++ {
+	for i := range 5 {
 		go func(id int) {
-			for j := 0; j < 100; j++ {
+			for j := range 100 {
 				err := ctx.Set("counter", id*1000+j)
 				if err != nil {
 					t.Errorf("Writer %d error: %v", id, err)
@@ -366,7 +366,7 @@ func TestGontext_ConcurrentAccess(t *testing.T) {
 	}
 
 	// Wait for all goroutines to complete
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		<-done
 	}
 }

config/maintenance/maintenance.go

@@ -3,6 +3,7 @@ package maintenance
 import (
 	"errors"
 	"fmt"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -70,13 +71,7 @@ func (c *Config) ValidateAndSetDefaults() error {
 		return nil
 	}
 	for _, day := range c.Every {
-		isDayValid := false
-		for _, longDayName := range longDayNames {
-			if day == longDayName {
-				isDayValid = true
-				break
-			}
-		}
+		isDayValid := slices.Contains(longDayNames, day)
 		if !isDayValid {
 			return errInvalidDayName
 		}
@@ -118,7 +113,7 @@ func (c *Config) IsUnderMaintenance() bool {
 	// Set to midnight prior to adding duration
 	dayWhereMaintenancePeriodWouldStart := time.Date(now.Year(), now.Month(), adjustedDate, 0, 0, 0, 0, now.Location())
 	hasMaintenanceEveryDay := len(c.Every) == 0
-	hasMaintenancePeriodScheduledToStartOnThatWeekday := c.hasDay(dayWhereMaintenancePeriodWouldStart.Weekday().String())
+	hasMaintenancePeriodScheduledToStartOnThatWeekday := slices.Contains(c.Every, dayWhereMaintenancePeriodWouldStart.Weekday().String())
 	if !hasMaintenanceEveryDay && !hasMaintenancePeriodScheduledToStartOnThatWeekday {
 		// The day when the maintenance period would start is not scheduled
 		// to have any maintenance, so we can just return false.
@@ -129,15 +124,6 @@ func (c *Config) IsUnderMaintenance() bool {
 	return now.After(startOfMaintenancePeriod) && now.Before(endOfMaintenancePeriod)
 }
 
-func (c *Config) hasDay(day string) bool {
-	for _, d := range c.Every {
-		if d == day {
-			return true
-		}
-	}
-	return false
-}
-
 func hhmmToDuration(s string) (time.Duration, error) {
 	if len(s) != 5 {
 		return 0, errInvalidMaintenanceStartFormat

config/tunneling/sshtunnel/sshtunnel.go

@@ -133,7 +133,7 @@ func (t *SSHTunnel) Dial(network, addr string) (net.Conn, error) {
 	const maxRetries = 3
 	const baseDelay = 500 * time.Millisecond
 	var lastErr error
-	for attempt := 0; attempt < maxRetries; attempt++ {
+	for attempt := range maxRetries {
 		if attempt > 0 {
 			// Exponential backoff: 500ms, 1s, 2s
 			delay := baseDelay << (attempt - 1)

config/util.go

@@ -4,13 +4,3 @@ package config
 func toPtr[T any](value T) *T {
 	return &value
 }
-
-// contains checks if a key exists in the slice
-func contains[T comparable](slice []T, key T) bool {
-	for _, item := range slice {
-		if item == key {
-			return true
-		}
-	}
-	return false
-}