freeze before exit when _MINIO_DEBUG_NO_EXIT is defined (#15709)

this is to ensure keep k8s pods running, when they reach a "crashloop" stage

cmd/main.go

@@ -23,11 +23,13 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"runtime/debug"
 	"sort"
 	"strings"
 
 	"github.com/minio/cli"
 	"github.com/minio/minio/internal/color"
+	"github.com/minio/minio/internal/logger"
 	"github.com/minio/pkg/console"
 	"github.com/minio/pkg/trie"
 	"github.com/minio/pkg/words"
@@ -189,8 +191,27 @@ func Main(args []string) {
 	// Set the minio app name.
 	appName := filepath.Base(args[0])
 
+	if os.Getenv("_MINIO_DEBUG_NO_EXIT") != "" {
+		freeze := func(_ int) {
+			// Infinite blocking op
+			<-make(chan struct{})
+		}
+
+		// Override the logger os.Exit()
+		logger.ExitFunc = freeze
+
+		defer func() {
+			if err := recover(); err != nil {
+				fmt.Println("panic:", err)
+				fmt.Println("")
+				fmt.Println(string(debug.Stack()))
+			}
+			freeze(-1)
+		}()
+	}
+
 	// Run the app - exit on error.
 	if err := newApp(appName).Run(args); err != nil {
-		os.Exit(1)
+		os.Exit(1) //nolint:gocritic
 	}
 }

internal/logger/console.go

@@ -32,6 +32,9 @@ import (
 // ConsoleLoggerTgt is a stringified value to represent console logging
 const ConsoleLoggerTgt = "console+http"
 
+// ExitFunc is called by Fatal() class functions, by default it calls os.Exit()
+var ExitFunc = os.Exit
+
 // Logger interface describes the methods that need to be implemented to satisfy the interface requirements.
 type Logger interface {
 	json(msg string, args ...interface{})
@@ -90,7 +93,7 @@ func (f fatalMsg) json(msg string, args ...interface{}) {
 	}
 	fmt.Println(string(logJSON))
 
-	os.Exit(1)
+	ExitFunc(1)
 }
 
 func (f fatalMsg) quiet(msg string, args ...interface{}) {
@@ -143,7 +146,7 @@ func (f fatalMsg) pretty(msg string, args ...interface{}) {
 	}
 
 	// Exit because this is a fatal error message
-	os.Exit(1)
+	ExitFunc(1)
 }
 
 type infoMsg struct{}