Improve implementation around config (#1122)

* refactor config

* fix saas config

* feat(config): scanmodule for each server in config.toml

* feat(config): enable to specify containersOnly in config.toml

* add new keys of config.toml to discover.go

* fix summary output, logging

config/scanmode.go

@@ -0,0 +1,110 @@
+package config
+
+import (
+	"strings"
+
+	"golang.org/x/xerrors"
+)
+
+// ScanMode has a type of scan mode. fast, fast-root, deep and offline
+type ScanMode struct {
+	flag byte
+}
+
+const (
+	// Fast is fast scan mode
+	Fast = byte(1 << iota)
+	// FastRoot is scanmode
+	FastRoot
+	// Deep is scanmode
+	Deep
+	// Offline is scanmode
+	Offline
+
+	fastStr     = "fast"
+	fastRootStr = "fast-root"
+	deepStr     = "deep"
+	offlineStr  = "offline"
+)
+
+// Set mode
+func (s *ScanMode) Set(f byte) {
+	s.flag |= f
+}
+
+// IsFast return whether scan mode is fast
+func (s ScanMode) IsFast() bool {
+	return s.flag&Fast == Fast
+}
+
+// IsFastRoot return whether scan mode is fastroot
+func (s ScanMode) IsFastRoot() bool {
+	return s.flag&FastRoot == FastRoot
+}
+
+// IsDeep return whether scan mode is deep
+func (s ScanMode) IsDeep() bool {
+	return s.flag&Deep == Deep
+}
+
+// IsOffline return whether scan mode is offline
+func (s ScanMode) IsOffline() bool {
+	return s.flag&Offline == Offline
+}
+
+func (s *ScanMode) ensure() error {
+	numTrue := 0
+	for _, b := range []bool{s.IsFast(), s.IsFastRoot(), s.IsDeep()} {
+		if b {
+			numTrue++
+		}
+	}
+	if numTrue == 0 {
+		s.Set(Fast)
+	} else if s.IsDeep() && s.IsOffline() {
+		return xerrors.New("Don't specify both of deep and offline")
+	} else if numTrue != 1 {
+		return xerrors.New("Specify only one of offline, fast, fast-root or deep")
+	}
+	return nil
+}
+
+func (s ScanMode) String() string {
+	ss := ""
+	if s.IsFast() {
+		ss = fastStr
+	} else if s.IsFastRoot() {
+		ss = fastRootStr
+	} else if s.IsDeep() {
+		ss = deepStr
+	}
+	if s.IsOffline() {
+		ss += " " + offlineStr
+	}
+	return ss + " mode"
+}
+
+func setScanMode(server *ServerInfo, d ServerInfo) error {
+	if len(server.ScanMode) == 0 {
+		server.ScanMode = Conf.Default.ScanMode
+	}
+	for _, m := range server.ScanMode {
+		switch strings.ToLower(m) {
+		case fastStr:
+			server.Mode.Set(Fast)
+		case fastRootStr:
+			server.Mode.Set(FastRoot)
+		case deepStr:
+			server.Mode.Set(Deep)
+		case offlineStr:
+			server.Mode.Set(Offline)
+		default:
+			return xerrors.Errorf("scanMode: %s of %s is invalid. Specify -fast, -fast-root, -deep or offline",
+				m, server.ServerName)
+		}
+	}
+	if err := server.Mode.ensure(); err != nil {
+		return xerrors.Errorf("%s in %s", err, server.ServerName)
+	}
+	return nil
+}