Merge pull request 'zone.ScanOptions, custom resolver and prevent unnecessary DNS calls' (#5)

Reviewed-on: #5

cmd/jpictl/config.go

@@ -14,6 +14,8 @@ var cfg = &Config{
 }
 
 // LoadZones loads all zones and machines in the config directory
-func (cfg *Config) LoadZones() (*zones.Zones, error) {
-	return zones.New(cfg.Base, cfg.Domain)
+func (cfg *Config) LoadZones(resolve bool) (*zones.Zones, error) {
+	return zones.New(cfg.Base, cfg.Domain,
+		zones.ResolvePublicAddresses(resolve),
+	)
 }

cmd/jpictl/dump.go

@@ -58,7 +58,7 @@ var dumpCmd = &cobra.Command{
 		var buf bytes.Buffer
 		var enc Encoder
 
-		m, err := cfg.LoadZones()
+		m, err := cfg.LoadZones(true)
 		if err != nil {
 			return err
 		}

cmd/jpictl/env.go

@@ -11,7 +11,7 @@ var envCmd = &cobra.Command{
 	Use:   "env",
 	Short: "generates environment variables for shell scripts",
 	RunE: func(_ *cobra.Command, _ []string) error {
-		m, err := cfg.LoadZones()
+		m, err := cfg.LoadZones(false)
 		if err != nil {
 			return err
 		}

cmd/jpictl/write.go

@@ -9,7 +9,7 @@ var writeCmd = &cobra.Command{
 	Use:   "write",
 	Short: "rewrites all config files",
 	RunE: func(_ *cobra.Command, _ []string) error {
-		m, err := cfg.LoadZones()
+		m, err := cfg.LoadZones(false)
 		if err != nil {
 			return err
 		}

pkg/zones/env.go

@@ -22,11 +22,23 @@ func (m *Zones) Env(export bool) *Env {
 	}
 }
 
+// Zones returns the list of Zone IDs
+func (m *Env) Zones() []int {
+	var zones []int
+
+	m.ForEachZone(func(z *Zone) bool {
+		zones = append(zones, z.ID)
+		return false
+	})
+
+	return zones
+}
+
 // WriteTo generates environment variables for shell scripts
 func (m *Env) WriteTo(w io.Writer) (int64, error) {
 	var buf bytes.Buffer
 
-	m.writeEnvVarFn(&buf, genEnvZones, "ZONES")
+	m.writeEnvVarInts(&buf, m.Zones(), "ZONES")
 	m.ForEachZone(func(z *Zone) bool {
 		m.writeEnvZone(&buf, z)
 		return false
@@ -45,25 +57,27 @@ func (m *Env) writeEnvZone(w io.Writer, z *Zone) {
 	m.writeEnvVar(w, z.Name, "ZONE%v_%s", zoneID, "NAME")
 
 	// ZONE{zoneID}_GW
-	gatewayID := getRingZeroGatewayID(z)
-	if gatewayID > 0 {
-		m.writeEnvVar(w, fmt.Sprintf("%v", gatewayID), "ZONE%v_%s", zoneID, "GW")
-
-		// ZONE{zoneID}_IP
-		if ip, ok := RingZeroAddress(zoneID, gatewayID); ok {
-			m.writeEnvVar(w, ip.String(), "ZONE%v_%s", zoneID, "IP")
-		}
-	}
+	gateways, _ := z.GatewayIDs()
+	m.writeEnvVarInts(w, gateways, "ZONE%v_%s", zoneID, "GW")
 }
 
-func (m *Env) writeEnvVarFn(w io.Writer, fn func(*Env) string, name string, args ...any) {
-	var value string
+func (m *Env) writeEnvVarInts(w io.Writer, value []int, name string, args ...any) {
+	var s string
 
-	if fn != nil {
-		value = fn(m)
+	if n := len(value); n > 0 {
+		var buf bytes.Buffer
+
+		for i, v := range value {
+			if i != 0 {
+				_, _ = fmt.Fprint(&buf, " ")
+			}
+			_, _ = fmt.Fprintf(&buf, "%v", v)
+		}
+
+		s = buf.String()
 	}
 
-	m.writeEnvVar(w, value, name, args...)
+	m.writeEnvVar(w, s, name, args...)
 }
 
 func (m *Env) writeEnvVar(w io.Writer, value string, name string, args ...any) {
@@ -84,35 +98,16 @@ func (m *Env) writeEnvVar(w io.Writer, value string, name string, args ...any) {
 	}
 }
 
-func genEnvZones(m *Env) string {
-	var s []string
-
-	m.ForEachZone(func(z *Zone) bool {
-		s = append(s, fmt.Sprintf("%v", z.ID))
-		return false
-	})
-
-	return strings.Join(s, " ")
-}
-
 func genEnvZoneNodes(z *Zone) string {
-	s := make([]string, 0, len(z.Machines))
-	for _, p := range z.Machines {
-		s = append(s, p.Name)
+	if n := z.Len(); n > 0 {
+		s := make([]string, 0, n)
+
+		z.ForEachMachine(func(p *Machine) bool {
+			s = append(s, p.Name)
+			return false
+		})
+
+		return strings.Join(s, " ")
 	}
-	return strings.Join(s, " ")
-}
-
-func getRingZeroGatewayID(z *Zone) int {
-	var gatewayID int
-
-	z.ForEachMachine(func(p *Machine) bool {
-		if p.IsGateway() {
-			gatewayID = p.ID
-		}
-
-		return gatewayID != 0
-	})
-
-	return gatewayID
+	return ""
 }

pkg/zones/machine_scan.go

@@ -7,8 +7,9 @@ import (
 	"time"
 )
 
-func (m *Machine) lookupNetIP() ([]netip.Addr, error) {
-	timeout := 2 * time.Second
+// LookupNetIP uses the DNS Resolver to get the public addresses associated
+// to a Machine
+func (m *Machine) LookupNetIP(timeout time.Duration) ([]netip.Addr, error) {
 	ctx, cancel := context.WithTimeout(context.Background(), timeout)
 
 	defer cancel()
@@ -16,8 +17,9 @@ func (m *Machine) lookupNetIP() ([]netip.Addr, error) {
 	return m.zone.zones.resolver.LookupNetIP(ctx, "ip", m.FullName())
 }
 
-func (m *Machine) updatePublicAddresses() error {
-	addrs, err := m.lookupNetIP()
+// UpdatePublicAddresses uses the DNS Resolver to set Machine.PublicAddresses
+func (m *Machine) UpdatePublicAddresses() error {
+	addrs, err := m.LookupNetIP(2 * time.Second)
 	if err != nil {
 		return err
 	}
@@ -52,12 +54,16 @@ func (m *Machine) setID() error {
 	return nil
 }
 
-func (m *Machine) scan() error {
+func (m *Machine) scan(opts *ScanOptions) error {
 	for i := 0; i < RingsCount; i++ {
 		if err := m.tryApplyWireguardConfig(i); err != nil {
 			return err
 		}
 	}
 
-	return m.updatePublicAddresses()
+	if !opts.DontResolvePublicAddresses {
+		return m.UpdatePublicAddresses()
+	}
+
+	return nil
 }

pkg/zones/options.go

@@ -0,0 +1,109 @@
+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 {
+	// DontResolvePublicAddresses indicates we shouldn't
+	// pre-populate Machine.PublicAddresses during the
+	// initial scan
+	DontResolvePublicAddresses bool
+}
+
+// ResolvePublicAddresses instructs the scanner to use
+// the DNS resolver to get PublicAddresses of nodes.
+// Default is true
+func ResolvePublicAddresses(resolve bool) ScanOption {
+	return func(m *Zones, opt *ScanOptions) error {
+		opt.DontResolvePublicAddresses = !resolve
+		return nil
+	}
+}
+
+// WithLookuper specifies what resolver.Lookuper to use to
+// find public addresses
+func WithLookuper(h resolver.Lookuper) ScanOption {
+	return func(m *Zones, opt *ScanOptions) error {
+		if h == nil {
+			return fs.ErrInvalid
+		}
+		m.resolver = resolver.NewResolver(h)
+		return nil
+	}
+}
+
+// WithResolver specifies what resolver to use to find
+// public addresses. if nil is passed, the [net.Resolver] will be used.
+// The default is using Cloudflare's 1.1.1.1.
+func WithResolver(h resolver.Resolver) ScanOption {
+	return func(m *Zones, opt *ScanOptions) error {
+		if h == nil {
+			h = resolver.SystemResolver(true)
+		}
+
+		m.resolver = h
+		return nil
+	}
+}
+
+func (m *Zones) setDefaults(opt *ScanOptions) error {
+	if m.resolver == nil {
+		h := resolver.NewCloudflareLookuper()
+
+		if err := WithLookuper(h)(m, opt); err != nil {
+			return err
+		}
+	}
+
+	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
+
+	z := &Zones{
+		dir:    dir,
+		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 {
@@ -46,16 +46,16 @@ func (m *Zones) scanDirectory() error {
 	return nil
 }
 
-func (m *Zones) scanMachines() error {
+func (m *Zones) scanMachines(opts *ScanOptions) error {
 	var err error
 	m.ForEachMachine(func(p *Machine) bool {
-		err = p.scan()
+		err = p.scan(opts)
 		return err != nil
 	})
 	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
@@ -93,12 +93,7 @@ func (m *Zones) scanSort() error {
 	})
 
 	m.ForEachZone(func(z *Zone) bool {
-		sort.SliceStable(z.Machines, func(i, j int) bool {
-			id1 := z.Machines[i].ID
-			id2 := z.Machines[j].ID
-			return id1 < id2
-		})
-
+		sort.Sort(z)
 		return false
 	})
 
@@ -116,7 +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

@@ -3,14 +3,15 @@ package zones
 
 import (
 	"io/fs"
-	"path/filepath"
-
-	"github.com/hack-pad/hackpadfs/os"
+	"sort"
 
 	"darvaza.org/resolver"
 )
 
 var (
+	_ MachineIterator = Machines(nil)
+	_ sort.Interface  = Machines(nil)
+
 	_ MachineIterator = (*Zone)(nil)
 	_ MachineIterator = (*Zones)(nil)
 	_ ZoneIterator    = (*Zones)(nil)
@@ -26,6 +27,62 @@ type ZoneIterator interface {
 	ForEachZone(func(*Zone) bool)
 }
 
+// Machines is a list of Machine objects
+type Machines []*Machine
+
+// ForEachMachine calls a function for each Machine in the list
+// until instructed to terminate the loop
+func (m Machines) ForEachMachine(fn func(*Machine) bool) {
+	for _, p := range m {
+		if fn(p) {
+			return
+		}
+	}
+}
+
+// Len returns the number of machines in the list
+func (m Machines) Len() int {
+	return len(m)
+}
+
+// Less implements sort.Interface to sort the list
+func (m Machines) Less(i, j int) bool {
+	a, b := m[i], m[j]
+	za, zb := a.Zone(), b.Zone()
+
+	switch {
+	case za == zb:
+		return a.ID < b.ID
+	default:
+		return za < zb
+	}
+}
+
+// Swap implements sort.Interface to sort the list
+func (m Machines) Swap(i, j int) {
+	m[i], m[j] = m[j], m[i]
+}
+
+// FilterMachines produces a subset of the machines offered by the given
+// iterator fulfilling a condition
+func FilterMachines(m MachineIterator, cond func(*Machine) bool) (Machines, int) {
+	var out []*Machine
+
+	if cond == nil {
+		// unconditional
+		cond = func(*Machine) bool { return true }
+	}
+
+	m.ForEachMachine(func(p *Machine) bool {
+		if cond(p) {
+			out = append(out, p)
+		}
+		return false
+	})
+
+	return out, len(out)
+}
+
 // Zone represents one zone in a cluster
 type Zone struct {
 	zones *Zones
@@ -33,23 +90,13 @@ type Zone struct {
 	ID   int    `toml:"id"`
 	Name string `toml:"name"`
 
-	Machines []*Machine `toml:"machines"`
+	Machines `toml:"machines"`
 }
 
 func (z *Zone) String() string {
 	return z.Name
 }
 
-// ForEachMachine calls a function for each Machine in the zone
-// until instructed to terminate the loop
-func (z *Zone) ForEachMachine(fn func(*Machine) bool) {
-	for _, p := range z.Machines {
-		if fn(p) {
-			return
-		}
-	}
-}
-
 // SetGateway configures a machine to be the zone's ring0 gateway
 func (z *Zone) SetGateway(gatewayID int, enabled bool) error {
 	var err error
@@ -75,6 +122,19 @@ func (z *Zone) SetGateway(gatewayID int, enabled bool) error {
 	}
 }
 
+// GatewayIDs returns the list of IDs of machines that act as ring0 gateways
+func (z *Zone) GatewayIDs() ([]int, int) {
+	var out []int
+	z.ForEachMachine(func(p *Machine) bool {
+		if p.IsGateway() {
+			out = append(out, p.ID)
+		}
+		return false
+	})
+
+	return out, len(out)
+}
+
 // Zones represents all zones in a cluster
 type Zones struct {
 	dir      fs.FS
@@ -127,35 +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)
-}