refactor: replace hand-rolled loops with stdlib slices and maps helpers

spinifex/ebsprovider/telemetry.go

@@ -3,6 +3,8 @@ package ebsprovider
 import (
 	"context"
 	"encoding/json"
+	"maps"
+	"slices"
 	"strings"
 
 	"github.com/nats-io/nats.go"
@@ -138,11 +140,7 @@ type headerCarrier nats.Header
 func (c headerCarrier) Get(key string) string { return nats.Header(c).Get(key) }
 func (c headerCarrier) Set(key, value string) { nats.Header(c).Set(key, value) }
 func (c headerCarrier) Keys() []string {
-	keys := make([]string, 0, len(c))
-	for key := range c {
-		keys = append(keys, key)
-	}
-	return keys
+	return slices.Collect(maps.Keys(c))
 }
 
 // startClientSpan opens a span for an outbound request and injects the trace

spinifex/gateway/hostmatch.go

@@ -2,6 +2,7 @@ package gateway
 
 import (
 	"context"
+	"net"
 	"net/http"
 	"strings"
 )
@@ -66,22 +67,12 @@ func parseRegistryHost(host, suffix string) (accountID, region string, ok bool)
 
 // stripPort removes a trailing :port from a host, leaving bare IPv6 intact.
 func stripPort(host string) string {
-	if host == "" {
-		return ""
+	if h, _, err := net.SplitHostPort(host); err == nil {
+		return h
 	}
-	// Bracketed IPv6 with optional port: [::1]:5000 or [::1].
-	if strings.HasPrefix(host, "[") {
-		if end := strings.IndexByte(host, ']'); end >= 0 {
-			return host[1:end]
-		}
-		return host
-	}
-	// Single colon means host:port; multiple colons mean bare IPv6, never a
-	// registry host, so leave it untouched.
-	if strings.Count(host, ":") == 1 {
-		if h, _, found := strings.Cut(host, ":"); found {
-			return h
-		}
+	// No port: unwrap a bracketed IPv6 literal, leave anything else as-is.
+	if h, ok := strings.CutPrefix(host, "["); ok {
+		return strings.TrimSuffix(h, "]")
 	}
 	return host
 }

spinifex/gateway/operations.go

@@ -1,7 +1,8 @@
 package gateway
 
 import (
-	"sort"
+	"maps"
+	"slices"
 
 	gateway_ecrapi "github.com/mulgadc/spinifex/spinifex/gateway/ecrapi"
 	gateway_ecs "github.com/mulgadc/spinifex/spinifex/gateway/ecs"
@@ -56,36 +57,18 @@ func AWSOperationInventory() map[string]ServiceOperationInventory {
 	}
 }
 
-func mapKeys[K ~string, V any](values map[K]V) []string {
-	keys := make([]string, 0, len(values))
-	for key := range values {
-		keys = append(keys, string(key))
-	}
-	sort.Strings(keys)
-	return keys
+func mapKeys[V any](values map[string]V) []string {
+	return slices.Sorted(maps.Keys(values))
 }
 
 func without(values, excluded []string) []string {
-	exclude := make(map[string]bool, len(excluded))
-	for _, value := range excluded {
-		exclude[value] = true
-	}
-	result := make([]string, 0, len(values))
-	for _, value := range values {
-		if !exclude[value] {
-			result = append(result, value)
-		}
-	}
-	return result
+	return slices.DeleteFunc(slices.Clone(values), func(value string) bool {
+		return slices.Contains(excluded, value)
+	})
 }
 
 func union(left, right []string) []string {
-	set := make(map[string]bool, len(left)+len(right))
-	for _, value := range left {
-		set[value] = true
-	}
-	for _, value := range right {
-		set[value] = true
-	}
-	return mapKeys(set)
+	merged := slices.Concat(left, right)
+	slices.Sort(merged)
+	return slices.Compact(merged)
 }

spinifex/handlers/dns/writer.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
+	"slices"
 	"strings"
 	"time"
 
@@ -249,21 +250,15 @@ func recordType(t string) (uint16, error) {
 // recordSetExists reports whether the zone already holds a record set for
 // (label, rtype); an upsert to it replaces in place and never grows the count.
 func recordSetExists(cfg nsconfig.ConfigArr, label string, rtype uint16) bool {
-	for _, r := range cfg.Records {
-		if strings.EqualFold(r.Domain, label) && r.Type == rtype {
-			return true
-		}
-	}
-	return false
+	return slices.ContainsFunc(cfg.Records, func(r nsconfig.Records) bool {
+		return strings.EqualFold(r.Domain, label) && r.Type == rtype
+	})
 }
 
 func hasUpsert(changes []Change) bool {
-	for _, c := range changes {
-		if c.Action == ActionUpsert {
-			return true
-		}
-	}
-	return false
+	return slices.ContainsFunc(changes, func(c Change) bool {
+		return c.Action == ActionUpsert
+	})
 }
 
 // northstarZoneConfig bundles the parsed service config with the writer's

spinifex/handlers/sts/web_identity_trust_policy.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"slices"
 	"strings"
 
 	"github.com/mulgadc/spinifex/spinifex/awserrors"
@@ -90,12 +91,9 @@ func matchWebIdentityStatement(actions []string, principalRaw, conditionRaw json
 }
 
 func matchWebIdentityAction(actions []string) bool {
-	for _, a := range actions {
-		if a == stsActionAssumeRoleWithWebIdentity || a == stsActionWildcard || a == globalWildcard {
-			return true
-		}
-	}
-	return false
+	return slices.ContainsFunc(actions, func(a string) bool {
+		return a == stsActionAssumeRoleWithWebIdentity || a == stsActionWildcard || a == globalWildcard
+	})
 }
 
 // matchFederatedPrincipal accepts Principal.Federated as a string or array.

spinifex/utils/nbd.go

@@ -131,13 +131,12 @@ func ParseNBDURI(nbdURI string) (serverType, path, host string, port int, err er
 	}
 
 	if after, ok := strings.CutPrefix(nbdURI, "nbd://"); ok {
-		hostPort := after
-		colonIdx := strings.LastIndex(hostPort, ":")
-		if colonIdx < 0 {
+		var portStr string
+		host, portStr, err = net.SplitHostPort(after)
+		if err != nil {
 			return "", "", "", 0, fmt.Errorf("missing port in NBD TCP URI: %s", nbdURI)
 		}
-		host = hostPort[:colonIdx]
-		port, err = strconv.Atoi(hostPort[colonIdx+1:])
+		port, err = strconv.Atoi(portStr)
 		if err != nil {
 			return "", "", "", 0, fmt.Errorf("invalid port in NBD URI: %s", nbdURI)
 		}

spinifex/vm/eni_reconcile.go

@@ -3,6 +3,8 @@ package vm
 import (
 	"fmt"
 	"log/slog"
+	"maps"
+	"slices"
 	"strconv"
 	"strings"
 )
@@ -139,11 +141,7 @@ func (m *Manager) ENISlotMapKeys(instance *VM) []string {
 	}
 	instance.ENIRequests.Mu.Lock()
 	defer instance.ENIRequests.Mu.Unlock()
-	out := make([]string, 0, len(instance.ENIRequests.AttachedByENIID))
-	for eniID := range instance.ENIRequests.AttachedByENIID {
-		out = append(out, eniID)
-	}
-	return out
+	return slices.Collect(maps.Keys(instance.ENIRequests.AttachedByENIID))
 }
 
 // CleanupENITap removes the tap + OVS port for an ENI. Exported wrapper over