feat(flag): replace '--slow' with '--parallel' (#5572)

Signed-off-by: knqyf263 <knqyf263@gmail.com>

pkg/flag/scan_flags.go

@@ -1,6 +1,8 @@
 package flag
 
 import (
+	"runtime"
+
 	"github.com/aquasecurity/trivy/pkg/log"
 	"github.com/aquasecurity/trivy/pkg/types"
 	xstrings "github.com/aquasecurity/trivy/pkg/x/strings"
@@ -70,6 +72,13 @@ var (
 		ConfigName: "scan.slow",
 		Default:    false,
 		Usage:      "scan over time with lower CPU and memory utilization",
+		Deprecated: true,
+	}
+	ParallelFlag = Flag{
+		Name:       "parallel",
+		ConfigName: "scan.parallel",
+		Default:    5,
+		Usage:      "number of goroutines enabled for parallel scanning, set 0 to auto-detect parallelism",
 	}
 	SBOMSourcesFlag = Flag{
 		Name:       "sbom-sources",
@@ -98,7 +107,8 @@ type ScanFlagGroup struct {
 	OfflineScan    *Flag
 	Scanners       *Flag
 	FilePatterns   *Flag
-	Slow           *Flag
+	Slow           *Flag // deprecated
+	Parallel       *Flag
 	SBOMSources    *Flag
 	RekorURL       *Flag
 	IncludeDevDeps *Flag
@@ -111,7 +121,7 @@ type ScanOptions struct {
 	OfflineScan    bool
 	Scanners       types.Scanners
 	FilePatterns   []string
-	Slow           bool
+	Parallel       int
 	SBOMSources    []string
 	RekorURL       string
 	IncludeDevDeps bool
@@ -124,10 +134,11 @@ func NewScanFlagGroup() *ScanFlagGroup {
 		OfflineScan:    &OfflineScanFlag,
 		Scanners:       &ScannersFlag,
 		FilePatterns:   &FilePatternsFlag,
-		Slow:           &SlowFlag,
+		Parallel:       &ParallelFlag,
 		SBOMSources:    &SBOMSourcesFlag,
 		RekorURL:       &RekorURLFlag,
 		IncludeDevDeps: &IncludeDevDepsFlag,
+		Slow:           &SlowFlag,
 	}
 }
 
@@ -143,6 +154,7 @@ func (f *ScanFlagGroup) Flags() []*Flag {
 		f.Scanners,
 		f.FilePatterns,
 		f.Slow,
+		f.Parallel,
 		f.SBOMSources,
 		f.RekorURL,
 		f.IncludeDevDeps,
@@ -155,6 +167,12 @@ func (f *ScanFlagGroup) ToOptions(args []string) (ScanOptions, error) {
 		target = args[0]
 	}
 
+	parallel := getInt(f.Parallel)
+	if f.Parallel != nil && parallel == 0 {
+		log.Logger.Infof("Set '--parallel' to the number of CPUs (%d)", runtime.NumCPU())
+		parallel = runtime.NumCPU()
+	}
+
 	return ScanOptions{
 		Target:         target,
 		SkipDirs:       getStringSlice(f.SkipDirs),
@@ -162,7 +180,7 @@ func (f *ScanFlagGroup) ToOptions(args []string) (ScanOptions, error) {
 		OfflineScan:    getBool(f.OfflineScan),
 		Scanners:       getUnderlyingStringSlice[types.Scanner](f.Scanners),
 		FilePatterns:   getStringSlice(f.FilePatterns),
-		Slow:           getBool(f.Slow),
+		Parallel:       parallel,
 		SBOMSources:    getStringSlice(f.SBOMSources),
 		RekorURL:       getString(f.RekorURL),
 		IncludeDevDeps: getBool(f.IncludeDevDeps),