refactor: Simplify code with modernize linter

.golangci.yml

@@ -41,6 +41,7 @@ linters:
     - govet
     - ineffassign
     - misspell
+    - modernize
     - revive
     - staticcheck
     - unused
@@ -74,6 +75,12 @@ linters:
 
       # tab width in spaces. Default to 1.
       tab-width: 1
+    modernize:
+      disable:
+        - any
+        - stringsbuilder
+        - omitzero
+        - waitgroup
     nakedret:
       # make an issue if func has more lines of code than this setting and it has naked returns; default is 30
       max-func-lines: 30

cmd/ec2geninfo/main.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"regexp"
+	"slices"
 	"text/template"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
@@ -157,11 +158,8 @@ func getEC2Instances(region string, instances map[string]InstanceInfo) (map[stri
 
 			cbrSupported := false
 			if inst.SupportedUsageClasses != nil {
-				for _, usageClass := range inst.SupportedUsageClasses {
-					if usageClass == types.UsageClassTypeCapacityBlock {
-						cbrSupported = true
-						break
-					}
+				if slices.Contains(inst.SupportedUsageClasses, types.UsageClassTypeCapacityBlock) {
+					cbrSupported = true
 				}
 			}
 

integration/tests/crud/creategetdelete_test.go

@@ -492,8 +492,8 @@ var _ = Describe("(Integration) Create, Get, Scale & Delete", func() {
 				Expect(js).To(ContainElement(HavePrefix("AWS_SESSION_OBJECT=")))
 
 				for _, envVar := range js {
-					if strings.HasPrefix(envVar, "AWS_SESSION_OBJECT=") {
-						err := json.Unmarshal([]byte(strings.TrimPrefix(envVar, "AWS_SESSION_OBJECT=")), &so)
+					if after, ok := strings.CutPrefix(envVar, "AWS_SESSION_OBJECT="); ok {
+						err := json.Unmarshal([]byte(after), &so)
 						Expect(err).ShouldNot(HaveOccurred())
 					}
 				}

integration/tests/dry_run/dry_run_test.go

@@ -167,7 +167,7 @@ var _ = Describe("(Integration) [Dry-Run test]", func() {
 	parseOutput := func(output []byte) (*api.ClusterConfig, *api.ClusterConfig) {
 		actual, err := eks.ParseConfig(output)
 		Expect(err).NotTo(HaveOccurred())
-		defaultConfig, err := eks.ParseConfig([]byte(fmt.Sprintf(defaultClusterConfig, params.ClusterName)))
+		defaultConfig, err := eks.ParseConfig(fmt.Appendf(nil, defaultClusterConfig, params.ClusterName))
 		Expect(err).NotTo(HaveOccurred())
 		return actual, defaultConfig
 	}

pkg/actions/accessentry/creator_test.go

@@ -28,11 +28,10 @@ var _ = Describe("Access Entry", func() {
 		s.CreateStackStub = func(ctx context.Context, stackName string, r builder.ResourceSetReader, tags map[string]string, parameters map[string]string, errorCh chan error) error {
 			defer close(errorCh)
 			prefix := fmt.Sprintf("eksctl-%s-accessentry-", ae.clusterName)
-			idx := strings.Index(stackName, prefix)
-			if idx < 0 {
+			_, suffix, ok := strings.Cut(stackName, prefix)
+			if !ok {
 				return fmt.Errorf("expected stack name to have prefix %q", prefix)
 			}
-			suffix := stackName[idx+len(prefix):]
 			_, err := base32.StdEncoding.WithPadding(base32.NoPadding).DecodeString(suffix)
 			if err != nil {
 				return fmt.Errorf("expected stack name to have a base32-encoded suffix: %w", err)

pkg/actions/accessentry/migrator_test.go

@@ -59,11 +59,10 @@ var _ = Describe("Migrate Access Entry", func() {
 		s.CreateStackStub = func(ctx context.Context, stackName string, r builder.ResourceSetReader, tags map[string]string, parameters map[string]string, errorCh chan error) error {
 			defer close(errorCh)
 			prefix := fmt.Sprintf("eksctl-%s-accessentry-", clusterName)
-			idx := strings.Index(stackName, prefix)
-			if idx < 0 {
+			_, suffix, ok := strings.Cut(stackName, prefix)
+			if !ok {
 				return fmt.Errorf("expected stack name to have prefix %q", prefix)
 			}
-			suffix := stackName[idx+len(prefix):]
 			_, err := base32.StdEncoding.WithPadding(base32.NoPadding).DecodeString(suffix)
 			if err != nil {
 				return fmt.Errorf("expected stack name to have a base32-encoded suffix: %w", err)

pkg/actions/addon/create.go

@@ -319,7 +319,7 @@ func (a *Manager) patchAWSNodeSA(ctx context.Context) error {
 		return nil
 	}
 
-	_, err = serviceAccounts.Patch(ctx, "aws-node", types.JSONPatchType, []byte(fmt.Sprintf(`[{"op": "remove", "path": "/metadata/managedFields/%d"}]`, managerIndex)), metav1.PatchOptions{})
+	_, err = serviceAccounts.Patch(ctx, "aws-node", types.JSONPatchType, fmt.Appendf(nil, `[{"op": "remove", "path": "/metadata/managedFields/%d"}]`, managerIndex), metav1.PatchOptions{})
 	if err != nil {
 		return fmt.Errorf("failed to patch sa: %w", err)
 	}
@@ -387,7 +387,7 @@ func (a *Manager) patchAWSNodeDaemonSet(ctx context.Context) error {
 		}
 	}
 
-	_, err = daemonSets.Patch(ctx, "aws-node", types.JSONPatchType, []byte(fmt.Sprintf(`[{"op": "remove", "path": "/metadata/managedFields/%d"}]`, managerIndex)), metav1.PatchOptions{})
+	_, err = daemonSets.Patch(ctx, "aws-node", types.JSONPatchType, fmt.Appendf(nil, `[{"op": "remove", "path": "/metadata/managedFields/%d"}]`, managerIndex), metav1.PatchOptions{})
 	if err != nil {
 		return fmt.Errorf("failed to patch daemon set: %w", err)
 	}

pkg/actions/anywhere/anywhere.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"slices"
 
 	"github.com/weaveworks/eksctl/pkg/version"
 )
@@ -26,10 +27,8 @@ func IsAnywhereCommand(args []string) (bool, error) {
 
 	// if they have any args/flags before the anywhere command we should error
 	// e.g. eksctl --foo=bar anywhere should error
-	for _, arg := range args {
-		if arg == "anywhere" {
-			return false, fmt.Errorf("flags cannot be placed before the anywhere command")
-		}
+	if slices.Contains(args, "anywhere") {
+		return false, fmt.Errorf("flags cannot be placed before the anywhere command")
 	}
 
 	return false, nil

pkg/actions/capability/creator.go

@@ -6,6 +6,7 @@ import (
 	"encoding/base32"
 	"errors"
 	"fmt"
+	"maps"
 	"strings"
 	"time"
 
@@ -128,9 +129,7 @@ func (c *Creator) createCapabilityStack(ctx context.Context, capability *api.Cap
 		api.ClusterNameTag:    c.clusterName,
 		api.CapabilityNameTag: capability.Name,
 	}
-	for k, v := range capability.Tags {
-		tags[k] = v
-	}
+	maps.Copy(tags, capability.Tags)
 	if err := c.stackCreator.CreateStack(ctx, stackName, rs, tags, nil, stackErrCh); err != nil {
 		return err
 	}
@@ -154,9 +153,7 @@ func (c *Creator) createIAMRoleStack(ctx context.Context, capability *api.Capabi
 		api.CapabilityIAMRoleTag: capability.Name,
 	}
 
-	for k, v := range capability.Tags {
-		tags[k] = v
-	}
+	maps.Copy(tags, capability.Tags)
 
 	stackCh := make(chan error)
 	if err := c.stackCreator.CreateStack(ctx, stackName, rs, tags, nil, stackCh); err != nil {

pkg/actions/karpenter/create_test.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"slices"
 
 	awseks "github.com/aws/aws-sdk-go-v2/service/eks"
 	ekstypes "github.com/aws/aws-sdk-go-v2/service/eks/types"
@@ -451,12 +452,7 @@ var _ = Describe("Create", func() {
 					Cluster: fakeCluster,
 				}, nil)
 				p.MockEC2().On("CreateTags", mock.Anything, mock.MatchedBy(func(input *ec2.CreateTagsInput) bool {
-					for _, r := range input.Resources {
-						if r == "sg-cluster-1234" {
-							return true
-						}
-					}
-					return false
+					return slices.Contains(input.Resources, "sg-cluster-1234")
 				})).Return(nil, errors.New("tag failed"))
 			})
 			It("errors", func() {

pkg/actions/nodegroup/delete_test.go

@@ -77,7 +77,6 @@ var _ = Describe("Delete", func() {
 			deleteNgTaskRuns atomic.Uint32
 		)
 		for _, stack := range dt.stacks {
-			stack := stack
 			deleteNgTasks = append(deleteNgTasks, &taskfakes.FakeTask{
 				DescribeStub: func() string {
 					return "delete " + stack.NodeGroupName

pkg/actions/nodegroup/drain.go

@@ -43,7 +43,6 @@ func (d *Drainer) Drain(ctx context.Context, input *DrainInput) error {
 
 	g, ctx := errgroup.WithContext(ctx)
 	for _, nodegroup := range input.NodeGroups {
-		nodegroup := nodegroup
 		g.Go(func() error {
 			nodeGroupDrainer := drain.NewNodeGroupDrainer(d.ClientSet, nodegroup, input.MaxGracePeriod, input.NodeDrainWaitPeriod, input.PodEvictionWaitPeriod, input.Undo, input.DisableEviction, input.Parallel)
 			return nodeGroupDrainer.Drain(ctx, sem)

pkg/actions/podidentityassociation/creator.go

@@ -46,7 +46,6 @@ func (c *Creator) CreateTasks(ctx context.Context, podIdentityAssociations []api
 		Parallel: true,
 	}
 	for _, pia := range podIdentityAssociations {
-		pia := pia
 		piaCreationTasks := &tasks.TaskTree{
 			Parallel:  false,
 			IsSubTask: true,

pkg/actions/podidentityassociation/deleter.go

@@ -118,7 +118,6 @@ func (d *Deleter) DeleteTasks(ctx context.Context, podIDs []Identifier) (*tasks.
 	}
 
 	for _, podID := range podIDs {
-		podID := podID
 		piaDeletionTasks := &tasks.TaskTree{
 			Parallel:  false,
 			IsSubTask: true,

pkg/addons/default/addons.go

@@ -3,6 +3,7 @@ package defaultaddons
 import (
 	"context"
 	"fmt"
+	"slices"
 
 	"github.com/aws/aws-sdk-go-v2/service/eks"
 
@@ -66,10 +67,8 @@ func supportsMultiArch(podSec corev1.PodSpec) bool {
 	for _, nodeSelectorTerm := range podSec.Affinity.NodeAffinity.RequiredDuringSchedulingIgnoredDuringExecution.NodeSelectorTerms {
 		for _, me := range nodeSelectorTerm.MatchExpressions {
 			if me.Key == corev1.LabelArchStable && me.Operator == corev1.NodeSelectorOpIn {
-				for _, val := range me.Values {
-					if val == "arm64" {
-						return true
-					}
+				if slices.Contains(me.Values, "arm64") {
+					return true
 				}
 			}
 		}

pkg/apis/eksctl.io/v1alpha5/nodegroups.go

@@ -1,17 +1,18 @@
 package v1alpha5
 
-import "fmt"
+import (
+	"fmt"
+	"slices"
+)
 
 // HasInstanceType returns whether some node in the group fulfils the type check
 func HasInstanceType(nodeGroup *NodeGroup, hasType func(string) bool) bool {
 	if hasType(nodeGroup.InstanceType) {
 		return true
 	}
 	if nodeGroup.InstancesDistribution != nil {
-		for _, instanceType := range nodeGroup.InstancesDistribution.InstanceTypes {
-			if hasType(instanceType) {
-				return true
-			}
+		if slices.ContainsFunc(nodeGroup.InstancesDistribution.InstanceTypes, hasType) {
+			return true
 		}
 	}
 	return false
@@ -22,12 +23,7 @@ func HasInstanceTypeManaged(nodeGroup *ManagedNodeGroup, hasType func(string) bo
 	if hasType(nodeGroup.InstanceType) {
 		return true
 	}
-	for _, instanceType := range nodeGroup.InstanceTypes {
-		if hasType(instanceType) {
-			return true
-		}
-	}
-	return false
+	return slices.ContainsFunc(nodeGroup.InstanceTypes, hasType)
 }
 
 // ClusterHasInstanceType checks all nodegroups and managed nodegroups for a specific instance type

pkg/apis/eksctl.io/v1alpha5/partitions.go

@@ -1,6 +1,9 @@
 package v1alpha5
 
-import "fmt"
+import (
+	"fmt"
+	"slices"
+)
 
 // Partitions.
 const (
@@ -153,10 +156,8 @@ var Partitions = partitions{
 
 func (p partitions) partitionFromRegion(region string) *partition {
 	for _, pt := range p {
-		for _, r := range pt.regions {
-			if r == region {
-				return &pt
-			}
+		if slices.Contains(pt.regions, region) {
+			return &pt
 		}
 	}
 	return nil

pkg/apis/eksctl.io/v1alpha5/types.go

@@ -7,6 +7,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"slices"
 	"strings"
 	"time"
 
@@ -1214,10 +1215,8 @@ func NewClusterIAM() *ClusterIAM {
 
 // AppendAvailabilityZone appends a new AZ to the set
 func (c *ClusterConfig) AppendAvailabilityZone(newAZ string) {
-	for _, az := range c.AvailabilityZones {
-		if az == newAZ {
-			return
-		}
+	if slices.Contains(c.AvailabilityZones, newAZ) {
+		return
 	}
 	c.AvailabilityZones = append(c.AvailabilityZones, newAZ)
 }

pkg/apis/eksctl.io/v1alpha5/validation.go

@@ -385,10 +385,8 @@ func validateCloudWatchLogging(clusterConfig *ClusterConfig) error {
 		}
 	}
 	if logRetentionDays := clusterConfig.CloudWatch.ClusterLogging.LogRetentionInDays; logRetentionDays != 0 {
-		for _, v := range LogRetentionInDaysValues {
-			if v == logRetentionDays {
-				return nil
-			}
+		if slices.Contains(LogRetentionInDaysValues, logRetentionDays) {
+			return nil
 		}
 		return fmt.Errorf("invalid value %d for logRetentionInDays; supported values are %v", logRetentionDays, LogRetentionInDaysValues)
 	}
@@ -468,14 +466,7 @@ func (c *ClusterConfig) ValidateVPCConfig() error {
 			return errors.New("vpc.hostnameType is not supported with a pre-existing VPC")
 		}
 		var hostnameType ec2types.HostnameType
-		found := false
-		for _, h := range hostnameType.Values() {
-			if h == ec2types.HostnameType(c.VPC.HostnameType) {
-				found = true
-				break
-			}
-		}
-		if !found {
+		if !slices.Contains(hostnameType.Values(), ec2types.HostnameType(c.VPC.HostnameType)) {
 			return fmt.Errorf("invalid value %q for vpc.hostnameType; supported values are %v", c.VPC.HostnameType, hostnameType.Values())
 		}
 	}
@@ -1614,12 +1605,7 @@ func validateNodeGroupKubeletExtraConfig(kubeletConfig *InlineDocument) error {
 }
 
 func isSupportedAMIFamily(imageFamily string) bool {
-	for _, image := range SupportedAMIFamilies() {
-		if imageFamily == image {
-			return true
-		}
-	}
-	return false
+	return slices.Contains(SupportedAMIFamilies(), imageFamily)
 }
 
 func supportedAMIFamiliesForOS(isOSImage func(string) bool) []string {

pkg/az/az.go

@@ -4,7 +4,8 @@ import (
 	"context"
 	"fmt"
 	"math/rand"
-	gostrings "strings"
+	"slices"
+	"strings"
 	"time"
 
 	"github.com/aws/aws-sdk-go-v2/aws"
@@ -15,7 +16,6 @@ import (
 	api "github.com/weaveworks/eksctl/pkg/apis/eksctl.io/v1alpha5"
 	"github.com/weaveworks/eksctl/pkg/awsapi"
 	"github.com/weaveworks/eksctl/pkg/utils/nodes"
-	"github.com/weaveworks/eksctl/pkg/utils/strings"
 )
 
 var zoneIDsToAvoid = map[string][]string{
@@ -115,7 +115,7 @@ func FilterBasedOnAvailability(ctx context.Context, zones []string, np []api.Nod
 		if len(noSupport) == 0 {
 			filteredList = append(filteredList, zone)
 		} else {
-			logger.Info("skipping %s from selection because it doesn't support the following instance type(s): %s", zone, gostrings.Join(noSupport, ","))
+			logger.Info("skipping %s from selection because it doesn't support the following instance type(s): %s", zone, strings.Join(noSupport, ","))
 		}
 	}
 	return filteredList, nil
@@ -162,7 +162,7 @@ func filterZones(region string, zones []ec2types.AvailabilityZone) []string {
 	var filteredZones []string
 	azsToAvoid := zoneIDsToAvoid[region]
 	for _, z := range zones {
-		if !strings.Contains(azsToAvoid, *z.ZoneId) {
+		if !slices.Contains(azsToAvoid, *z.ZoneId) {
 			filteredZones = append(filteredZones, *z.ZoneName)
 		}
 	}