Add flag to filter debug logs

This allows for only a subset of commands to be logged to reduce the
amount of logging generated.

Updates #7999

PiperOrigin-RevId: 480476369

runsc/cli/main.go

@@ -147,8 +147,10 @@ func Main(version string) {
 	// propagate it to child processes.
 	refs.SetLeakMode(conf.ReferenceLeak)
 
+	subcommand := flag.CommandLine.Arg(0)
+
 	// Set up logging.
-	if conf.Debug {
+	if conf.Debug && specutils.IsDebugCommand(conf, subcommand) {
 		log.SetLevel(log.Debug)
 	}
 
@@ -164,15 +166,13 @@ func Main(version string) {
 	// case that does not occur.
 	_ = time.Local.String()
 
-	subcommand := flag.CommandLine.Arg(0)
-
 	var e log.Emitter
 	if *debugLogFD > -1 {
 		f := os.NewFile(uintptr(*debugLogFD), "debug log file")
 
 		e = newEmitter(conf.DebugLogFormat, f)
 
-	} else if conf.DebugLog != "" {
+	} else if len(conf.DebugLog) > 0 && specutils.IsDebugCommand(conf, subcommand) {
 		f, err := specutils.DebugLogFile(conf.DebugLog, subcommand, "" /* name */)
 		if err != nil {
 			util.Fatalf("error opening debug log file in %q: %v", conf.DebugLog, err)

runsc/config/config.go

@@ -53,6 +53,11 @@ type Config struct {
 	// DebugLog is the path to log debug information to, if not empty.
 	DebugLog string `flag:"debug-log"`
 
+	// DebugCommand is a comma-separated list of commands to be debugged if
+	// --debug-log is also set. Empty means debug all. "!" negates the expression.
+	// E.g. "create,start" or "!boot,events".
+	DebugCommand string `flag:"debug-command"`
+
 	// PanicLog is the path to log GO's runtime messages, if not empty.
 	PanicLog string `flag:"panic-log"`
 

runsc/config/flags.go

@@ -41,6 +41,7 @@ func RegisterFlags(flagSet *flag.FlagSet) {
 
 	// Debugging flags.
 	flagSet.String("debug-log", "", "additional location for logs. If it ends with '/', log files are created inside the directory with default names. The following variables are available: %TIMESTAMP%, %COMMAND%.")
+	flagSet.String("debug-command", "", `comma-separated list of commands to be debugged if --debug-log is also set. Empty means debug all. "!" negates the expression. E.g. "create,start" or "!boot,events"`)
 	flagSet.String("panic-log", "", "file path where panic reports and other Go's runtime messages are written.")
 	flagSet.String("coverage-report", "", "file path where Go coverage reports are written. Reports will only be generated if runsc is built with --collect_code_coverage and --instrumentation_filter Bazel flags.")
 	flagSet.Bool("log-packets", false, "enable network packet logging.")

runsc/container/container.go

@@ -871,8 +871,10 @@ func (c *Container) createGoferProcess(spec *specs.Spec, conf *config.Config, bu
 				test = t
 			}
 		}
-		if err := donations.DonateDebugLogFile("debug-log-fd", conf.DebugLog, "gofer", test); err != nil {
-			return nil, nil, err
+		if specutils.IsDebugCommand(conf, "gofer") {
+			if err := donations.DonateDebugLogFile("debug-log-fd", conf.DebugLog, "gofer", test); err != nil {
+				return nil, nil, err
+			}
 		}
 	}
 

runsc/sandbox/sandbox.go

@@ -550,8 +550,10 @@ func (s *Sandbox) createSandboxProcess(conf *config.Config, args *Args, startSyn
 			test = t
 		}
 	}
-	if err := donations.DonateDebugLogFile("debug-log-fd", conf.DebugLog, "boot", test); err != nil {
-		return err
+	if specutils.IsDebugCommand(conf, "boot") {
+		if err := donations.DonateDebugLogFile("debug-log-fd", conf.DebugLog, "boot", test); err != nil {
+			return err
+		}
 	}
 	if err := donations.DonateDebugLogFile("panic-log-fd", conf.PanicLog, "panic", test); err != nil {
 		return err

runsc/specutils/specutils.go

@@ -412,6 +412,28 @@ func DebugLogFile(logPattern, command, test string) (*os.File, error) {
 	return os.OpenFile(logPattern, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0664)
 }
 
+// IsDebugCommand returns true if the command should be debugged or not, based
+// on the current configuration.
+func IsDebugCommand(conf *config.Config, command string) bool {
+	if len(conf.DebugCommand) == 0 {
+		// Debug everything by default.
+		return true
+	}
+	filter := conf.DebugCommand
+	rv := true
+	if filter[0] == '!' {
+		// Negate the match, e.g. !boot should log all, but "boot".
+		filter = filter[1:]
+		rv = false
+	}
+	for _, cmd := range strings.Split(filter, ",") {
+		if cmd == command {
+			return rv
+		}
+	}
+	return !rv
+}
+
 // SafeSetupAndMount creates the mount point and calls Mount with the given
 // flags. procPath is the path to procfs. If it is "", procfs is assumed to be
 // mounted at /proc.