zones: introduce ScanOption/ScanOptions for New()/NewFS()

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/zones/options.go

@@ -0,0 +1,63 @@
+package zones
+
+import (
+	"io/fs"
+	"path/filepath"
+
+	"darvaza.org/resolver"
+	"github.com/hack-pad/hackpadfs/os"
+)
+
+// A ScanOption preconfigures the Zones before scanning
+type ScanOption func(*Zones, *ScanOptions) error
+
+// ScanOptions contains flags used by the initial scan
+type ScanOptions struct{}
+
+func (*Zones) setDefaults(_ *ScanOptions) error {
+	return nil
+}
+
+// NewFS builds a [Zones] tree using the given directory
+func NewFS(dir fs.FS, domain string, opts ...ScanOption) (*Zones, error) {
+	var scanOptions ScanOptions
+
+	lockuper := resolver.NewCloudflareLookuper()
+
+	z := &Zones{
+		dir:      dir,
+		resolver: resolver.NewResolver(lockuper),
+		domain:   domain,
+	}
+
+	for _, opt := range opts {
+		if err := opt(z, &scanOptions); err != nil {
+			return nil, err
+		}
+	}
+
+	if err := z.setDefaults(&scanOptions); err != nil {
+		return nil, err
+	}
+
+	if err := z.scan(&scanOptions); err != nil {
+		return nil, err
+	}
+
+	return z, nil
+}
+
+// New builds a [Zones] tree using the given directory
+func New(dir, domain string, opts ...ScanOption) (*Zones, error) {
+	dir, err := filepath.Abs(dir)
+	if err != nil {
+		return nil, err
+	}
+
+	base, err := os.NewFS().Sub(dir[1:])
+	if err != nil {
+		return nil, err
+	}
+
+	return NewFS(base, domain, opts...)
+}

pkg/zones/scan.go

@@ -5,15 +5,15 @@ import (
 	"sort"
 )
 
-func (m *Zones) scan() error {
-	for _, fn := range []func() error{
+func (m *Zones) scan(opts *ScanOptions) error {
+	for _, fn := range []func(*ScanOptions) error{
 		m.scanDirectory,
 		m.scanMachines,
 		m.scanZoneIDs,
 		m.scanSort,
 		m.scanGateways,
 	} {
-		if err := fn(); err != nil {
+		if err := fn(opts); err != nil {
 			return err
 		}
 	}
@@ -21,7 +21,7 @@ func (m *Zones) scan() error {
 	return nil
 }
 
-func (m *Zones) scanDirectory() error {
+func (m *Zones) scanDirectory(_ *ScanOptions) error {
 	// each directory is a zone
 	entries, err := fs.ReadDir(m.dir, ".")
 	if err != nil {
@@ -46,7 +46,7 @@ func (m *Zones) scanDirectory() error {
 	return nil
 }
 
-func (m *Zones) scanMachines() error {
+func (m *Zones) scanMachines(_ *ScanOptions) error {
 	var err error
 	m.ForEachMachine(func(p *Machine) bool {
 		err = p.scan()
@@ -55,7 +55,7 @@ func (m *Zones) scanMachines() error {
 	return err
 }
 
-func (m *Zones) scanZoneIDs() error {
+func (m *Zones) scanZoneIDs(_ *ScanOptions) error {
 	var hasMissing bool
 	var lastZoneID int
 
@@ -85,7 +85,7 @@ func (m *Zones) scanZoneIDs() error {
 	return nil
 }
 
-func (m *Zones) scanSort() error {
+func (m *Zones) scanSort(_ *ScanOptions) error {
 	sort.SliceStable(m.Zones, func(i, j int) bool {
 		id1 := m.Zones[i].ID
 		id2 := m.Zones[j].ID
@@ -111,7 +111,7 @@ func (m *Zones) scanSort() error {
 	return nil
 }
 
-func (m *Zones) scanGateways() error {
+func (m *Zones) scanGateways(_ *ScanOptions) error {
 	var err error
 
 	m.ForEachZone(func(z *Zone) bool {

pkg/zones/zones.go

@@ -3,11 +3,8 @@ package zones
 
 import (
 	"io/fs"
-	"path/filepath"
 	"sort"
 
-	"github.com/hack-pad/hackpadfs/os"
-
 	"darvaza.org/resolver"
 )
 
@@ -190,35 +187,3 @@ func (m *Zones) GetMachineByName(name string) (*Machine, bool) {
 
 	return out, out != nil
 }
-
-// NewFS builds a [Zones] tree using the given directory
-func NewFS(dir fs.FS, domain string) (*Zones, error) {
-	lockuper := resolver.NewCloudflareLookuper()
-
-	z := &Zones{
-		dir:      dir,
-		resolver: resolver.NewResolver(lockuper),
-		domain:   domain,
-	}
-
-	if err := z.scan(); err != nil {
-		return nil, err
-	}
-
-	return z, nil
-}
-
-// New builds a [Zones] tree using the given directory
-func New(dir, domain string) (*Zones, error) {
-	dir, err := filepath.Abs(dir)
-	if err != nil {
-		return nil, err
-	}
-
-	base, err := os.NewFS().Sub(dir[1:])
-	if err != nil {
-		return nil, err
-	}
-
-	return NewFS(base, domain)
-}