Enable prealloc linter (elastic#1728)

.golangci.yaml

@@ -22,6 +22,14 @@ linters:
     - unparam
     - unused
     - whitespace
+    - prealloc
+
+issues:
+  exclude-rules:
+    - path: _test\.go
+      linters: [prealloc]
+    - path: resources/utils/testhelper/*.go
+      linters: [prealloc]
 
 linters-settings:
   gocritic:
@@ -129,3 +137,8 @@ linters-settings:
     local-variables-are-used: false
   tenv:
     all: true
+
+  prealloc:
+    simple: true
+    range-loops: true
+    for-loops: false

deploy/cloudformation/gomain.go

@@ -153,7 +153,7 @@ func createStack(stackName string, templatePath string, params map[string]string
 	}
 
 	svc := cloudformation.NewFromConfig(cfg)
-	var cfParams []types.Parameter
+	cfParams := make([]types.Parameter, 0, len(params))
 	for key, value := range params {
 		p := types.Parameter{
 			ParameterKey:   aws.String(key),

evaluator/logger.go

@@ -74,7 +74,7 @@ func (l *logger) SetLevel(level logging.Level) {
 }
 
 func mapToArray(m map[string]any) []any {
-	var ret []any
+	ret := make([]any, 0, len(m))
 	for k, v := range m {
 		ret = append(ret, k, v)
 	}

flavors/benchmark/aws_org.go

@@ -112,7 +112,7 @@ func (a *AWSOrg) getAwsAccounts(ctx context.Context, log *logp.Logger, initialCf
 		return nil, err
 	}
 
-	var accounts []preset.AwsAccount
+	accounts := make([]preset.AwsAccount, 0, len(accountIdentities))
 	for _, identity := range accountIdentities {
 		var memberCfg awssdk.Config
 		if identity.Account == rootIdentity.Account {

resources/fetching/registry/registry.go

@@ -67,7 +67,7 @@ func NewRegistry(log *logp.Logger, options ...Option) Registry {
 }
 
 func (r *registry) Keys() []string {
-	var keys []string
+	keys := make([]string, 0, len(r.reg))
 	for k := range r.reg {
 		keys = append(keys, k)
 	}

resources/providers/aws_cis/logging/provider.go

@@ -45,7 +45,7 @@ func (p *Provider) DescribeTrails(ctx context.Context) ([]awslib.AwsResource, er
 		return nil, trailsErr
 	}
 
-	var enrichedTrails []awslib.AwsResource
+	enrichedTrails := make([]awslib.AwsResource, 0, len(trails))
 	for _, info := range trails {
 		if info.Trail.S3BucketName == nil {
 			continue

resources/providers/awslib/cloudtrail/provider.go

@@ -45,7 +45,7 @@ func (p Provider) DescribeTrails(ctx context.Context) ([]TrailInfo, error) {
 		return nil, err
 	}
 
-	var result []TrailInfo
+	result := make([]TrailInfo, 0, len(output.TrailList))
 	for _, trail := range output.TrailList {
 		if trail.Name == nil {
 			continue

resources/providers/awslib/ec2/provider.go

@@ -30,9 +30,11 @@ import (
 	"github.com/elastic/cloudbeat/resources/providers/awslib"
 )
 
-var subnetAssociationIdFilterName = "association.subnet-id"
-var subnetVpcIdFilterName = "vpc-id"
-var subnetMainAssociationFilterName = "association.main"
+var (
+	subnetAssociationIdFilterName   = "association.subnet-id"
+	subnetVpcIdFilterName           = "vpc-id"
+	subnetMainAssociationFilterName = "association.main"
+)
 
 type Provider struct {
 	log          *logp.Logger
@@ -219,7 +221,7 @@ func (p *Provider) CreateSnapshots(ctx context.Context, ins *Ec2Instance) ([]EBS
 		return nil, err
 	}
 
-	var result []EBSSnapshot
+	result := make([]EBSSnapshot, 0, len(res.Snapshots))
 	for _, snap := range res.Snapshots {
 		result = append(result, FromSnapshotInfo(snap, ins.Region, p.awsAccountID, *ins))
 	}
@@ -241,7 +243,7 @@ func (p *Provider) DescribeSnapshots(ctx context.Context, snapshot EBSSnapshot)
 		return nil, err
 	}
 
-	var result []EBSSnapshot
+	result := make([]EBSSnapshot, 0, len(res.Snapshots))
 	for _, snap := range res.Snapshots {
 		result = append(result, FromSnapshot(snap, snapshot.Region, p.awsAccountID, snapshot.Instance))
 	}
@@ -268,10 +270,11 @@ func (p *Provider) GetRouteTableForSubnet(ctx context.Context, region string, su
 	}
 
 	// Fetching route tables explicitly attached to the subnet
-	routeTables, err := client.DescribeRouteTables(ctx, &ec2.DescribeRouteTablesInput{Filters: []types.Filter{
-		{Name: &subnetAssociationIdFilterName, Values: []string{subnetId}}},
+	routeTables, err := client.DescribeRouteTables(ctx, &ec2.DescribeRouteTablesInput{
+		Filters: []types.Filter{
+			{Name: &subnetAssociationIdFilterName, Values: []string{subnetId}},
+		},
 	})
-
 	if err != nil {
 		return types.RouteTable{}, err
 	}

resources/providers/awslib/iam/policy.go

@@ -216,13 +216,12 @@ func (p Provider) listInlinePolicies(ctx context.Context, identity *string) ([]P
 		input.Marker = output.Marker
 	}
 
-	var policies []PolicyDocument
+	policies := make([]PolicyDocument, 0, len(policyNames))
 	for i := range policyNames {
 		inlinePolicy, err := p.client.GetUserPolicy(ctx, &iamsdk.GetUserPolicyInput{
 			PolicyName: &policyNames[i],
 			UserName:   identity,
 		})
-
 		if err != nil {
 			p.log.Errorf("fail to get inline policy for user: %s, policy name: %s", *identity, policyNames[i])
 			policies = append(policies, PolicyDocument{PolicyName: policyNames[i]})

resources/providers/awslib/iam/user.go

@@ -43,7 +43,6 @@ const (
 )
 
 func (p Provider) GetUsers(ctx context.Context) ([]awslib.AwsResource, error) {
-	var users []awslib.AwsResource
 	apiUsers, err := p.listUsers(ctx)
 	if err != nil {
 		p.log.Errorf("fail to list users, error: %v", err)
@@ -60,6 +59,7 @@ func (p Provider) GetUsers(ctx context.Context) ([]awslib.AwsResource, error) {
 		apiUsers = append(apiUsers, *rootUser)
 	}
 
+	users := make([]awslib.AwsResource, 0, len(apiUsers))
 	var userAccount *CredentialReport
 	for _, apiUser := range apiUsers {
 		var username string
@@ -182,7 +182,7 @@ func (p Provider) listMFADevices(ctx context.Context, user types.User) ([]AuthDe
 		input.Marker = output.Marker
 	}
 
-	var devices []AuthDevice
+	devices := make([]AuthDevice, 0, len(apiDevices))
 	for _, apiDevice := range apiDevices {
 		isVirtual := true
 		if !strings.HasPrefix(*apiDevice.SerialNumber, "arn:") {
@@ -243,7 +243,7 @@ func (p Provider) getCredentialReport(ctx context.Context) (map[string]*Credenti
 		}
 
 		// loop until max retries or till the report is ready
-		var countRetries = 0
+		countRetries := 0
 		report, err = p.client.GetCredentialReport(ctx, &iamsdk.GetCredentialReportInput{})
 		if errors.As(err, &apiErr) {
 			for apiErr.ErrorCode() == "NoSuchEntity" || apiErr.ErrorCode() == "ReportInProgress" {

resources/providers/awslib/rds/provider.go

@@ -84,7 +84,7 @@ func (p Provider) DescribeDBInstances(ctx context.Context) ([]awslib.AwsResource
 }
 
 func (p Provider) getDBInstanceSubnets(ctx context.Context, region string, dbInstance types.DBInstance) []Subnet {
-	var results []Subnet
+	results := make([]Subnet, 0, len(dbInstance.DBSubnetGroup.Subnets))
 	for _, subnet := range dbInstance.DBSubnetGroup.Subnets {
 		resultSubnet := Subnet{ID: *subnet.SubnetIdentifier, RouteTable: nil}
 		routeTableForSubnet, err := p.ec2.GetRouteTableForSubnet(ctx, region, *subnet.SubnetIdentifier, *dbInstance.DBSubnetGroup.VpcId)

resources/providers/awslib/rds/provider_test.go

@@ -38,8 +38,10 @@ type ProviderTestSuite struct {
 	suite.Suite
 }
 
-type rdsClientMockReturnVals map[string]map[string][]any
-type ec2GetRouteTableForSubnetVals [][]any
+type (
+	rdsClientMockReturnVals       map[string]map[string][]any
+	ec2GetRouteTableForSubnetVals [][]any
+)
 
 var (
 	identifier           = "identifier"
@@ -115,7 +117,7 @@ func (s *ProviderTestSuite) TestProvider_DescribeDBInstances() {
 					StorageEncrypted:        false,
 					AutoMinorVersionUpgrade: false,
 					PubliclyAccessible:      false,
-					Subnets:                 []Subnet(nil),
+					Subnets:                 []Subnet{},
 					region:                  awslib.DefaultRegion,
 				},
 				DBInstance{
@@ -128,8 +130,10 @@ func (s *ProviderTestSuite) TestProvider_DescribeDBInstances() {
 						{ID: identifier2, RouteTable: &RouteTable{
 							ID:     identifier,
 							Routes: []Route{{DestinationCidrBlock: &destinationCidrBlock, GatewayId: &gatewayId}},
-						}}},
-					region: awslib.DefaultRegion},
+						}},
+					},
+					region: awslib.DefaultRegion,
+				},
 			},
 		},
 	}

resources/providers/gcplib/inventory/provider.go

@@ -379,7 +379,7 @@ func decodeDnsPolicies(dnsPolicyAssets []*assetpb.Asset) []*dnsPolicyFields {
 // getAssetsByProject groups assets by project, extracts metadata for each project, and adds folder and organization-level resources for each group.
 func getAssetsByProject[T any](assets []*ExtendedGcpAsset, log *logp.Logger, f TypeGenerator[T]) []*T {
 	assetsByProject := lo.GroupBy(assets, func(asset *ExtendedGcpAsset) string { return asset.Ecs.ProjectId })
-	var enrichedAssets []*T
+	enrichedAssets := make([]*T, 0, len(assetsByProject))
 	for projectId, projectAssets := range assetsByProject {
 		if projectId == "" {
 			continue
@@ -439,7 +439,7 @@ func mergeAssetContentType(assets []*assetpb.Asset) []*assetpb.Asset {
 			item.IamPolicy = asset.IamPolicy
 		}
 	}
-	var results []*assetpb.Asset
+	results := make([]*assetpb.Asset, 0, len(resultsMap))
 	for _, asset := range resultsMap {
 		results = append(results, asset)
 	}
@@ -448,7 +448,7 @@ func mergeAssetContentType(assets []*assetpb.Asset) []*assetpb.Asset {
 
 // extends the assets with the project and organization display name
 func extendWithECS(ctx context.Context, crm *ResourceManagerWrapper, cache map[string]*fetching.EcsGcp, assets []*assetpb.Asset) []*ExtendedGcpAsset {
-	var extendedAssets []*ExtendedGcpAsset
+	extendedAssets := make([]*ExtendedGcpAsset, 0, len(assets))
 	for _, asset := range assets {
 		keys := getAssetIds(asset)
 		cacheKey := fmt.Sprintf("%s/%s", keys.parentProject, keys.parentOrg)

resources/utils/testhelper/helper.go

@@ -70,15 +70,15 @@ func CollectResourcesWithTimeout[T any](ch chan T, maxCount int, timeout time.Du
 // This function waits for the channel to close before returning.
 // See CollectResources for a non-blocking version of the function.
 func CollectResourcesBlocking[T any](ch chan T) []T {
-	var results []T
+	results := make([]T, 0)
 	for v := range ch {
 		results = append(results, v)
 	}
 	return results
 }
 
 func CreateMockClients[T any](client T, regions []string) map[string]T {
-	var m = make(map[string]T, 0)
+	m := make(map[string]T, 0)
 	for _, clientRegion := range regions {
 		m[clientRegion] = client
 	}