rings: introduce RingID and a Ring placeholder

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

Makefile

@@ -15,7 +15,8 @@ TMPDIR ?= .tmp
 REVIVE ?= $(GOBIN)/revive
 REVIVE_CONF ?= $(TOOLSDIR)/revive.toml
 REVIVE_RUN_ARGS ?= -config $(REVIVE_CONF) -formatter friendly
-REVIVE_INSTALL_URL ?= github.com/mgechev/revive@master
+REVIVE_VERSION ?= v1.3.7
+REVIVE_INSTALL_URL ?= github.com/mgechev/revive@$(REVIVE_VERSION)
 
 GO_INSTALL_URLS = \
 	$(REVIVE_INSTALL_URL) \

pkg/rings/rings.go

@@ -3,21 +3,25 @@
 package rings
 
 import (
+	"fmt"
+	"strconv"
 	"syscall"
 
 	"darvaza.org/core"
 )
 
 const (
+	// RingMax indicates the highest [Ring] identifier
+	RingMax = 4
 	// RegionMax indicates the highest number that can be used for a [RegionID].
 	RegionMax = (1 << 4) - 1
 	// ZoneMax indicates the highest number that can be used for a [ZoneID].
 	ZoneMax = (1 << 4) - 1
 	// NodeMax indicates the highest number that can be used for a [NodeID].
-	NodeMax = (1 << 12) - 1
+	NodeMax = (1 << 12) - 2
 	// NodeZeroMax indicates the highest number that can be used for a [NodeID]
 	// when its a gateway connected to Ring 0 (backbone).
-	NodeZeroMax = (1 << 8) - 1
+	NodeZeroMax = (1 << 8) - 2
 
 	// RingZeroBits indicates the size of the prefix on the ring 0 (backbone) network.
 	RingZeroBits = 16
@@ -31,18 +35,41 @@ const (
 	RingThreeBits = 12
 )
 
+// RingID identifies a Ring
+type RingID int
+
+// Valid tells a [RingID] is within the valid range.
+func (n RingID) Valid() bool { return n > 0 && n <= RingMax }
+
+func (n RingID) String() string {
+	return idString(n)
+}
+
+// A Ring identifies what ring an address belongs to
+type Ring interface {
+	ID() RingID
+}
+
 // RegionID is the identifier of a region, valid between 1 and [RegionMax].
 type RegionID int
 
 // Valid tells a [RegionID] is within the valid range.
 func (n RegionID) Valid() bool { return n > 0 && n <= RegionMax }
 
+func (n RegionID) String() string {
+	return idString(n)
+}
+
 // ZoneID is the identifier of a zone within a region, valid between 1 and [ZoneMax].
 type ZoneID int
 
 // Valid tells a [ZoneID] is within the valid range.
 func (n ZoneID) Valid() bool { return n > 0 && n <= ZoneMax }
 
+func (n ZoneID) String() string {
+	return idString(n)
+}
+
 // NodeID is the identifier of a machine within a zone of a region, valid between
 // 1 and [NodeMax], but between 1 and [NodeZeroMax] if it will be a zone gateway.
 type NodeID int
@@ -53,8 +80,28 @@ func (n NodeID) Valid() bool { return n > 0 && n <= NodeMax }
 // ValidZero tells a [NodeID] is within the valid range for a gateway.
 func (n NodeID) ValidZero() bool { return n > 0 && n <= NodeZeroMax }
 
+func (n NodeID) String() string {
+	return idString(n)
+}
+
 // ErrOutOfRange is an error indicating the value of a field
 // is out of range.
 func ErrOutOfRange[T ~int | ~uint32](value T, field string) error {
 	return core.Wrap(syscall.EINVAL, "%s out of range (%v)", field, value)
 }
+
+type intID interface {
+	~int
+	Valid() bool
+}
+
+func idString[T intID](p T) string {
+	switch {
+	case p == 0:
+		return "unspecified"
+	case p.Valid():
+		return strconv.Itoa(int(p))
+	default:
+		return fmt.Sprintf("invalid (%v)", int(p))
+	}
+}