zones: introduce Zone.GatewayIDs()

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

pkg/wireguard/keys.go

@@ -51,12 +51,12 @@ func (pub PublicKey) String() string {
 	}
 }
 
-// MarshalJSON encodes the key for JSON, omiting empty.
+// MarshalJSON encodes the key for JSON, omitting empty.
 func (key PrivateKey) MarshalJSON() ([]byte, error) {
 	return encodeKeyJSON(key.String())
 }
 
-// MarshalJSON encodes the key for JSON, omiting empty.
+// MarshalJSON encodes the key for JSON, omitting empty.
 func (pub PublicKey) MarshalJSON() ([]byte, error) {
 	return encodeKeyJSON(pub.String())
 }
@@ -70,12 +70,12 @@ func encodeKeyJSON(s string) ([]byte, error) {
 	return out, nil
 }
 
-// MarshalYAML encodes the key for YAML, omiting empty.
+// MarshalYAML encodes the key for YAML, omitting empty.
 func (key PrivateKey) MarshalYAML() (any, error) {
 	return encodeKeyYAML(key.String())
 }
 
-// MarshalYAML encodes the key for YAML, omiting empty.
+// MarshalYAML encodes the key for YAML, omitting empty.
 func (pub PublicKey) MarshalYAML() (any, error) {
 	return encodeKeyYAML(pub.String())
 }

pkg/zones/env.go

@@ -32,11 +32,14 @@ func (m *Zones) writeEnvZone(w io.Writer, z *Zone) {
 
 	// ZONE{zoneID}_GW
 	gatewayID := getRingZeroGatewayID(z)
-	m.writeEnvVar(w, fmt.Sprintf("%v", gatewayID), "ZONE%v_%s", zoneID, "GW")
+	if gatewayID > 0 {
+		m.writeEnvVar(w, fmt.Sprintf("%v", gatewayID), "ZONE%v_%s", zoneID, "GW")
 
-	// ZONE{zoneID}_IP
-	ip, _ := RingZeroAddress(zoneID, gatewayID)
-	m.writeEnvVar(w, ip.String(), "ZONE%v_%s", zoneID, "IP")
+		// ZONE{zoneID}_IP
+		if ip, ok := RingZeroAddress(zoneID, gatewayID); ok {
+			m.writeEnvVar(w, ip.String(), "ZONE%v_%s", zoneID, "IP")
+		}
+	}
 }
 
 func (m *Zones) writeEnvVarFn(w io.Writer, fn func(*Zones) string, name string, args ...any) {
@@ -79,13 +82,9 @@ func genEnvZoneNodes(z *Zone) string {
 }
 
 func getRingZeroGatewayID(z *Zone) int {
-	var firstNodeID, gatewayID int
+	var gatewayID int
 
 	z.ForEachMachine(func(p *Machine) bool {
-		if firstNodeID == 0 {
-			firstNodeID = p.ID
-		}
-
 		if p.IsGateway() {
 			gatewayID = p.ID
 		}
@@ -93,10 +92,5 @@ func getRingZeroGatewayID(z *Zone) int {
 		return gatewayID != 0
 	})
 
-	switch {
-	case gatewayID == 0:
-		return firstNodeID
-	default:
-		return gatewayID
-	}
+	return gatewayID
 }

pkg/zones/machine.go

@@ -43,6 +43,24 @@ func (m *Machine) IsGateway() bool {
 	return ok
 }
 
+// SetGateway enables/disables a Machine ring0 integration
+func (m *Machine) SetGateway(enabled bool) error {
+	ri, found := m.getRingInfo(0)
+	switch {
+	case !found && !enabled:
+		return nil
+	case !found:
+		var err error
+
+		if ri, err = m.createRingInfo(0, false); err != nil {
+			return err
+		}
+	}
+
+	ri.Enabled = enabled
+	return m.SyncWireguardConfig(0)
+}
+
 // Zone indicates the [Zone] this machine belongs to
 func (m *Machine) Zone() int {
 	return m.zone.ID

pkg/zones/machine_rings.go

@@ -228,3 +228,23 @@ func (m *Machine) RemoveWireguardConfig(ring int) error {
 
 	return err
 }
+
+func (m *Machine) createRingInfo(ring int, enabled bool) (*RingInfo, error) {
+	keys, err := wireguard.NewKeyPair()
+	if err != nil {
+		return nil, err
+	}
+
+	ri := &RingInfo{
+		Ring:    ring,
+		Enabled: enabled,
+		Keys:    keys,
+	}
+
+	err = m.applyRingInfo(ring, ri)
+	if err != nil {
+		return nil, err
+	}
+
+	return ri, nil
+}

pkg/zones/scan.go

@@ -11,6 +11,7 @@ func (m *Zones) scan() error {
 		m.scanMachines,
 		m.scanZoneIDs,
 		m.scanSort,
+		m.scanGateways,
 	} {
 		if err := fn(); err != nil {
 			return err
@@ -92,12 +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
 	})
 
@@ -115,6 +111,16 @@ func (m *Zones) scanSort() error {
 	return nil
 }
 
+func (m *Zones) scanGateways() error {
+	var err error
+
+	m.ForEachZone(func(z *Zone) bool {
+		_, _, err = z.GetGateway()
+		return err != nil
+	})
+	return err
+}
+
 func (z *Zone) scan() error {
 	// each directory is a machine
 	entries, err := fs.ReadDir(z.zones.dir, z.Name)
@@ -139,3 +145,41 @@ func (z *Zone) scan() error {
 
 	return nil
 }
+
+// GetGateway returns the first gateway found, if none
+// files will be created to enable the first [Machine] to
+// be one
+func (z *Zone) GetGateway() (*Machine, bool, error) {
+	var first *Machine
+	var gateway *Machine
+
+	z.zones.ForEachMachine(func(p *Machine) bool {
+		switch {
+		case p.IsGateway():
+			// found
+			gateway = p
+		case first == nil:
+			// remember
+			first = p
+		default:
+			// keep looking
+		}
+
+		return gateway != nil
+	})
+
+	switch {
+	case gateway != nil:
+		// found one
+		return gateway, false, nil
+	case first != nil:
+		// make one
+		if err := first.SetGateway(true); err != nil {
+			return first, false, err
+		}
+		return first, true, nil
+	default:
+		// Zone without nodes?
+		panic("unreachable")
+	}
+}

pkg/zones/wireguard.go

@@ -16,6 +16,7 @@ var (
 
 	_ WireguardConfigSyncer = (*Zones)(nil)
 	_ WireguardConfigSyncer = (*Zone)(nil)
+	_ WireguardConfigSyncer = (*Machine)(nil)
 
 	_ WireguardKeysWriter = (*Zones)(nil)
 	_ WireguardKeysWriter = (*Zone)(nil)
@@ -200,6 +201,12 @@ func syncWireguardConfig(z ZoneIterator, m MachineIterator, ring int) error {
 	return err
 }
 
+// SyncWireguardConfig updates all wgN.conf files for the specified
+// ring
+func (m *Machine) SyncWireguardConfig(ring int) error {
+	return m.zone.SyncWireguardConfig(ring)
+}
+
 // A WireguardKeysWriter writes the Wireguard Keys for all machines
 // under its scope for the specified ring
 type WireguardKeysWriter interface {

pkg/zones/zones.go

@@ -4,6 +4,7 @@ package zones
 import (
 	"io/fs"
 	"path/filepath"
+	"sort"
 
 	"github.com/hack-pad/hackpadfs/os"
 
@@ -11,6 +12,9 @@ import (
 )
 
 var (
+	_ MachineIterator = Machines(nil)
+	_ sort.Interface  = Machines(nil)
+
 	_ MachineIterator = (*Zone)(nil)
 	_ MachineIterator = (*Zones)(nil)
 	_ ZoneIterator    = (*Zones)(nil)
@@ -26,6 +30,62 @@ 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 +93,51 @@ 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
+	var found bool
+
+	z.ForEachMachine(func(p *Machine) bool {
+		if p.ID == gatewayID {
+			found = true
+			err = p.SetGateway(enabled)
+
+			return true
 		}
+		return false
+	})
+
+	switch {
+	case err != nil:
+		return err
+	case !found:
+		return fs.ErrNotExist
+	default:
+		return nil
 	}
 }
 
+// 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