schema/notify: ty.Type

These correspond to the TYPE produced by keepalived's notify events.

It may be one of: INSTANCE,GROUP,VS,RS as of this commit.

Our focus is only on supporting VRRP event types at present, but we do
recognize all the current event types.

  TYPE INSTANCE STATE PRIORITY
  ^^^^

schema/notify/ty/flags.go

@@ -0,0 +1,84 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+package ty
+
+import "strings"
+
+const (
+	// Zero value
+	NULL Type = 0
+	// VRRP Instance event
+	INSTANCE = 1 << iota
+	// VRRP Group event
+	GROUP
+	// IPVS Virtual Server event (unused)
+	VS
+	// IPVS Real Server event (unused)
+	RS
+
+	VRRP = INSTANCE | GROUP
+	IPVS = VS | RS
+
+	UNKNOWN = NULL
+)
+
+var (
+	s2ty map[string]Type = map[string]Type{
+		"INSTANCE": INSTANCE,
+		"GROUP":    GROUP,
+		"VS":       VS,
+		"RS":       RS,
+	}
+)
+
+func ParseType(i string) Type {
+	i = strings.TrimSpace(i)
+
+	t, ok := s2ty[i]
+	if !ok {
+		return UNKNOWN
+	}
+
+	return t
+}
+
+type Type uint8
+
+func (t Type) Has(flag Type) bool {
+	return t&flag != 0
+}
+
+func (t Type) IsVRRP() bool {
+	return t.Has(INSTANCE) || t.Has(GROUP)
+}
+
+func (t Type) IsIPVS() bool {
+	return t.Has(VS) || t.Has(RS)
+}
+
+func (t Type) String() string {
+	if t.IsVRRP() {
+		if t.Has(INSTANCE) {
+			return "INSTANCE"
+		}
+
+		if t.Has(GROUP) {
+			return "GROUP"
+		}
+	} else if t.IsIPVS() {
+		if t.Has(VS) {
+			return "VS"
+		}
+		if t.Has(RS) {
+			return "RS"
+		}
+	} else if t == UNKNOWN {
+		return "UNKNOWN"
+	}
+
+	panic("missing case in notify/state/flags.go:String()")
+}