Fix: add option overwriteList

Due to MaxMind mmdb file format constraint,
the IPs and/or CIDRs of the latter written list
will overwrite those of the former one
when duplicated data is found.

To make sure that the lists you added include
all their own IPs and/or CIDRs, you must place
the name of the most important list at last
in option wantedList and option overwriteList
of type maxmindMMDB in config file.

The option overwriteList of type maxmindMMDB
is used when the IPs and/or CIDRs of some lists
in generated mmdb file overlap.

For example, if you change the CIDRs of the list "cn",
and generate the full version of Country.mmdb file
which is with all countries(lists), the option overwriteList
must include "cn", so that the "cn" list will be written at last,
which ensures it includes all the CIDRs you specify.

If the option wantedList of type maxmindMMDB is specified,
no need for option overwriteList.

1 files changed, 58 insertions, 27 deletions

diff --git a/plugin/maxmind/mmdb.go b/plugin/maxmind/mmdb.go
index 4e0ec242..26440101 100644
--- a/plugin/maxmind/mmdb.go
+++ b/plugin/maxmind/mmdb.go
@@ -38,6 +38,7 @@ func newMMDB(action lib.Action, data json.RawMessage) (lib.OutputConverter, erro
 		OutputName string     `json:"outputName"`
 		OutputDir  string     `json:"outputDir"`
 		Want       []string   `json:"wantedList"`
+		Overwrite  []string   `json:"overwriteList"`
 		OnlyIPType lib.IPType `json:"onlyIPType"`
 	}
 
@@ -62,6 +63,7 @@ func newMMDB(action lib.Action, data json.RawMessage) (lib.OutputConverter, erro
 		OutputName:  tmp.OutputName,
 		OutputDir:   tmp.OutputDir,
 		Want:        tmp.Want,
+		Overwrite:   tmp.Overwrite,
 		OnlyIPType:  tmp.OnlyIPType,
 	}, nil
 }
@@ -73,6 +75,7 @@ type mmdb struct {
 	OutputName  string
 	OutputDir   string
 	Want        []string
+	Overwrite   []string
 	OnlyIPType  lib.IPType
 }
 
@@ -89,14 +92,6 @@ func (m *mmdb) GetDescription() string {
 }
 
 func (m *mmdb) Output(container lib.Container) error {
-	// Filter want list
-	wantList := make(map[string]bool)
-	for _, want := range m.Want {
-		if want = strings.ToUpper(strings.TrimSpace(want)); want != "" {
-			wantList[want] = true
-		}
-	}
-
 	writer, err := mmdbwriter.New(
 		mmdbwriter.Options{
 			DatabaseType:            "GeoLite2-Country",
@@ -110,27 +105,16 @@ func (m *mmdb) Output(container lib.Container) error {
 	}
 
 	updated := false
-	switch len(wantList) {
-	case 0:
-		for entry := range container.Loop() {
-			if err := m.marshalData(writer, entry); err != nil {
-				return err
-			}
-			updated = true
+	for _, name := range m.getEntryNameListInOrder(container) {
+		entry, found := container.GetEntry(name)
+		if !found {
+			log.Printf("❌ entry %s not found", name)
+			continue
 		}
-
-	default:
-		for name := range wantList {
-			entry, found := container.GetEntry(name)
-			if !found {
-				log.Printf("❌ entry %s not found", name)
-				continue
-			}
-			if err := m.marshalData(writer, entry); err != nil {
-				return err
-			}
-			updated = true
+		if err := m.marshalData(writer, entry); err != nil {
+			return err
 		}
+		updated = true
 	}
 
 	if updated {
@@ -144,6 +128,53 @@ func (m *mmdb) Output(container lib.Container) error {
 	return nil
 }
 
+func (m *mmdb) getEntryNameListInOrder(container lib.Container) []string {
+	/*
+		Note: The IPs and/or CIDRs of the latter list will overwrite those of the former one
+		when duplicated data found due to MaxMind mmdb file format constraint.
+
+		Be sure to place the name of the most important list at last
+		when writing wantedList and overwriteList in config file.
+
+		The order of names in wantedList has a higher priority than which of the overwriteList.
+	*/
+
+	wantList := make([]string, 0, 200)
+	for _, want := range m.Want {
+		if want = strings.ToUpper(strings.TrimSpace(want)); want != "" {
+			wantList = append(wantList, want)
+		}
+	}
+
+	if len(wantList) > 0 {
+		return wantList
+	}
+
+	overwriteList := make([]string, 0, 200)
+	overwriteMap := make(map[string]bool)
+	for _, overwrite := range m.Overwrite {
+		if overwrite = strings.ToUpper(strings.TrimSpace(overwrite)); overwrite != "" {
+			overwriteList = append(overwriteList, overwrite)
+			overwriteMap[overwrite] = true
+		}
+	}
+
+	list := make([]string, 0, 200)
+	for entry := range container.Loop() {
+		name := entry.GetName()
+		_, found := overwriteMap[name]
+		if found {
+			continue
+		}
+		list = append(list, name)
+	}
+
+	// Make sure the names in overwriteList are written at last
+	list = append(list, overwriteList...)
+
+	return list
+}
+
 func (m *mmdb) marshalData(writer *mmdbwriter.Tree, entry *lib.Entry) error {
 	var entryCidr []string
 	var err error