chore: enable depguard to block log

.golangci.yml

@@ -15,6 +15,7 @@ linters:
     - bodyclose # checks whether HTTP response body is closed successfully
     - canonicalheader # checks whether net/http.Header uses canonical header keys
     - decorder # checks declaration order of types, consts, vars, and funcs
+    - depguard # blocks imports of packages with a preferred replacement
     - durationcheck # checks for two durations multiplied together
     - embeddedstructfieldcheck # checks embedded sync.Mutex/RWMutex in structs
     - errcheck # checks for unchecked errors in type assertions and I/O
@@ -23,7 +24,6 @@ linters:
     - errorlint # catches ==/!= on errors, type assertions on errors, and %v instead of %w — all break on wrapped errors
     - exptostd # detects golang.org/x/exp/ functions replaceable by stdlib
     - fatcontext # detects nested contexts in loops
-    - forcetypeassert # flags unchecked type assertions that can panic
     - gocheckcompilerdirectives # validates go compiler directive comments (//go:)
     - godot # checks that declaration comments end in a period
     - goprintffuncname # checks that printf-like functions are named with f at the end
@@ -57,8 +57,17 @@ linters:
     embeddedstructfieldcheck:
       forbid-mutex: true
 
+    depguard:
+      rules:
+        main:
+          deny:
+            - pkg: log$
+              desc: Use log/slog instead, see https://go.dev/blog/slog
+            - pkg: math/rand$
+              desc: Use math/rand/v2 instead, see https://go.dev/blog/randv2
+
     errcheck:
-      check-type-assertions: true
+      check-type-assertions: true # replaces forcetypeassert
       exclude-functions:
         - (*github.com/nats-io/nats.go.Subscription).Unsubscribe # cleanup-only, errors not actionable
 

cmd/dhcptest/main.go

@@ -14,7 +14,7 @@ import (
 	"context"
 	"flag"
 	"fmt"
-	"log"
+	"log/slog"
 	"net"
 	"os"
 	"os/exec"
@@ -46,18 +46,21 @@ func main() {
 	case *spinifexID != "":
 		hwAddr, err = net.ParseMAC(generateMAC(*spinifexID))
 		if err != nil {
-			log.Fatalf("generateMAC(%q): %v", *spinifexID, err)
+			slog.Error("Could not parse generated MAC", "spinifex-id", *spinifexID, "error", err)
+			os.Exit(1)
 		}
 		fmt.Printf("spinifex virtual MAC for %q: %s\n", *spinifexID, hwAddr)
 	case *macStr != "":
 		hwAddr, err = net.ParseMAC(*macStr)
 		if err != nil {
-			log.Fatalf("parse --mac %q: %v", *macStr, err)
+			slog.Error("Could not parse --mac", "mac", *macStr, "error", err)
+			os.Exit(1)
 		}
 	default:
 		hwAddr, err = ifaceMAC(*iface)
 		if err != nil {
-			log.Fatalf("get MAC for %s: %v", *iface, err)
+			slog.Error("Could not get MAC for interface", "iface", *iface, "error", err)
+			os.Exit(1)
 		}
 		fmt.Printf("using real interface MAC: %s\n", hwAddr)
 	}
@@ -83,7 +86,7 @@ func main() {
 
 	if *promisc {
 		if err := setPromisc(*iface, true); err != nil {
-			log.Printf("WARNING: failed to set promisc on %s: %v", *iface, err)
+			slog.Warn("Failed to set promisc on interface", "iface", *iface, "error", err)
 		} else {
 			fmt.Printf("set %s promisc ON\n\n", *iface)
 		}
@@ -96,12 +99,13 @@ func main() {
 		nclient4.WithRetry(*retries),
 	}
 	if *verbose {
-		opts = append(opts, nclient4.WithLogger(nclient4.ShortSummaryLogger{Printfer: log.New(os.Stderr, "[nclient4] ", 0)}))
+		opts = append(opts, nclient4.WithLogger(nclient4.ShortSummaryLogger{Printfer: slogPrintfer{}}))
 	}
 
 	client, err := nclient4.New(*iface, opts...)
 	if err != nil {
-		log.Fatalf("nclient4.New(%s): %v", *iface, err)
+		slog.Error("Could not create nclient4 client", "iface", *iface, "error", err)
+		os.Exit(1)
 	}
 	defer client.Close()
 
@@ -141,6 +145,14 @@ func main() {
 	}
 }
 
+// slogPrintfer adapts nclient4's Printfer to slog. nclient4 only emits through
+// it under --verbose, so the packet summaries log at info level to stay visible.
+type slogPrintfer struct{}
+
+func (slogPrintfer) Printf(format string, v ...any) {
+	slog.Info(fmt.Sprintf(format, v...), "component", "nclient4")
+}
+
 // generateMAC is the same deterministic hash used by vpcd's topology.go.
 // It produces a locally-administered MAC (02:00:00:xx:xx:xx) from a resource ID.
 func generateMAC(resourceID string) string {

spinifex/gateway/ec2/instance/placement.go

@@ -6,7 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
-	"math/rand"
+	"math/rand/v2"
 	"sort"
 	"sync"
 	"time"

spinifex/network/external/dhcp/manager.go

@@ -6,7 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"log/slog"
-	"math/rand"
+	"math/rand/v2"
 	"net"
 	"sync"
 	"time"
@@ -704,5 +704,5 @@ func jitter(span time.Duration) time.Duration {
 	if span <= 0 {
 		return 0
 	}
-	return time.Duration(rand.Int63n(int64(span*2))) - span //nolint:gosec // jitter, not cryptographic
+	return time.Duration(rand.Int64N(int64(span*2))) - span //nolint:gosec // jitter, not cryptographic
 }

tests/e2e/ddil/scenarios/main_test.go

@@ -7,7 +7,7 @@ package scenarios
 
 import (
 	"context"
-	"log"
+	"log/slog"
 	"os"
 	"os/signal"
 	"sync"
@@ -64,12 +64,12 @@ func setupCluster() (*harness.Cluster, harness.SSH, error) {
 // DDIL_DRY_RUN=1 skips cluster init and leaves only TestCoverageDrift active.
 func TestMain(m *testing.M) {
 	if dryRun() {
-		log.Printf("ddil: DDIL_DRY_RUN=1 — planned scenarios: %v (TestCoverageDrift will still execute)", scenarioLetters)
+		slog.Info("ddil: DDIL_DRY_RUN=1, TestCoverageDrift will still execute", "planned_scenarios", scenarioLetters)
 	}
 
 	c, s, err := setupCluster()
 	if err != nil {
-		log.Printf("ddil: cluster setup failed (continuing, scenarios will skip): %v", err)
+		slog.Warn("ddil: cluster setup failed, continuing and scenarios will skip", "error", err)
 	}
 
 	stop := installSignalHandler(c, s)
@@ -92,12 +92,12 @@ func installSignalHandler(c *harness.Cluster, s harness.SSH) func() {
 	go func() {
 		select {
 		case sig := <-ch:
-			log.Printf("ddil: received %s, cleaning up before exit", sig)
+			slog.Info("ddil: received signal, cleaning up before exit", "signal", sig)
 			if c != nil && s != nil {
 				ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
 				defer cancel()
 				if err := harness.ResetAllNodes(ctx, c, s); err != nil {
-					log.Printf("ddil: ResetAllNodes on signal: %v", err)
+					slog.Error("ddil: ResetAllNodes on signal failed", "error", err)
 				}
 				_ = s.Close()
 			}