rings: introduce ring-specific decoders

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

pkg/rings/decode.go

@@ -72,3 +72,51 @@ func unsafeDecodeAddress[T ~uint | NodeID](a, b, c, d byte) (RingID, RegionID, Z
 		return k, r, 0, n
 	}
 }
+
+// DecodeRingZeroAddress attempts to extract region, zone and node identifiers
+// from a given ring 0 address.
+//
+// revive:disable:function-result-limit
+func DecodeRingZeroAddress(addr netip.Addr) (RegionID, ZoneID, NodeID, bool) {
+	// revive:enable:function-result-limit
+	k, r, z, n := DecodeAddress[NodeID](addr)
+	if k == RingZeroID {
+		return r, z, n, true
+	}
+
+	return 0, 0, 0, false
+}
+
+// DecodeRingOneAddress attempts to extract region, zone and node identifiers
+// from a given ring 1 address.
+//
+// revive:disable:function-result-limit
+func DecodeRingOneAddress(addr netip.Addr) (RegionID, ZoneID, NodeID, bool) {
+	// revive:enable:function-result-limit
+	k, r, z, n := DecodeAddress[NodeID](addr)
+	if k == RingOneID {
+		return r, z, n, true
+	}
+
+	return 0, 0, 0, false
+}
+
+// DecodeRingTwoAddress attempts to extract region and unique identifier for
+// a kubernetes service from a given ring 2 address.
+func DecodeRingTwoAddress(addr netip.Addr) (RegionID, uint, bool) {
+	k, r, _, n := DecodeAddress[uint](addr)
+	if k == RingTwoID {
+		return r, n, true
+	}
+	return 0, 0, false
+}
+
+// DecodeRingThreeAddress attempts to extract region and unique identifier for
+// a kubernetes pod from a given ring 3 address.
+func DecodeRingThreeAddress(addr netip.Addr) (RegionID, uint, bool) {
+	k, r, _, n := DecodeAddress[uint](addr)
+	if k == RingThreeID {
+		return r, n, true
+	}
+	return 0, 0, false
+}

pkg/rings/decode_test.go

@@ -0,0 +1,53 @@
+package rings
+
+import (
+	"fmt"
+	"net/netip"
+	"testing"
+)
+
+func TestDecodeRingZeroAddress(t *testing.T) {
+	RZNDecodeTest(t, "DecodeRingZeroAddress", DecodeRingZeroAddress, []RZNDecodeTestCase{
+		{1, 1, 50, MustParseAddr("10.0.17.50"), true},
+		{1, 2, 50, MustParseAddr("10.0.18.50"), true},
+		{2, 3, 1, MustParseAddr("10.0.35.1"), true},
+	})
+}
+
+func TesDecodetRingOneAddress(t *testing.T) {
+	RZNDecodeTest(t, "DecodeRingOneAddress", DecodeRingOneAddress, []RZNDecodeTestCase{
+		{1, 1, 50, MustParseAddr("10.1.16.50"), true},
+		{1, 2, 50, MustParseAddr("10.1.32.50"), true},
+		{2, 3, 300, MustParseAddr("10.2.49.44"), true},
+	})
+}
+
+type RZNDecodeTestCase struct {
+	region RegionID
+	zone   ZoneID
+	node   NodeID
+	addr   netip.Addr
+	ok     bool
+}
+
+func RZNDecodeTest(t *testing.T,
+	fnName string, fn func(netip.Addr) (RegionID, ZoneID, NodeID, bool),
+	cases []RZNDecodeTestCase) {
+	//
+	for i, tc := range cases {
+		s := fmt.Sprintf("%s(%q)", fnName, tc.addr)
+
+		r, z, n, ok := fn(tc.addr)
+
+		switch {
+		case ok != tc.ok, r != tc.region, z != tc.zone, n != tc.node:
+			t.Errorf("ERROR: [%v/%v]: %s → %v %v %v %v (expected %v %v %v %v)",
+				i, len(cases), s,
+				r, z, n, ok,
+				tc.region, tc.zone, tc.node, tc.ok)
+		default:
+			t.Logf("[%v/%v]: %s → %v %v %v %v", i, len(cases), s,
+				r, z, n, ok)
+		}
+	}
+}