AM-S3, WirePattern: a per-machine state reaches its machine's keys below it; buscompose exports WirePattern

The per-machine form gains the keys below the machine's own, <node>.>, for every
per-machine state and a membership's too (PerMachineKeys), every module's key keeping
its form; buscompose exports WirePattern, which a reader uses to turn a stream's events
into the bus's subjects (the tool runner's marks).

Builds: design 46 7-approval-mark §13, §5

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h

go/buscompose/modstreams.go

@@ -3,6 +3,7 @@ package buscompose
 import (
 	"fmt"
 	"sort"
+	"strings"
 )
 
 // moduleStreamPrefix starts every subject a module's own stream takes.
@@ -14,6 +15,19 @@ func ModuleStreamSubject(module, event string) string {
 	return moduleStreamPrefix + module + ".event." + event
 }
 
+// WirePattern is a stream's local event pattern as the bus spells it: `**` is `>`, `*` stays `*`. A reader turns a
+// stream's events into the bus's subjects with it (design 46 7-approval-mark §5): the grants part composing a stream, and
+// the tool runner deriving a restricted stream's marked subjects.
+func WirePattern(local string) string {
+	parts := strings.Split(local, ".")
+	for i, p := range parts {
+		if p == "**" {
+			parts[i] = ">"
+		}
+	}
+	return strings.Join(parts, ".")
+}
+
 // A ModuleStream is one module's declared stream as the bus holds it.
 type ModuleStream struct {
 	Module string

go/buscompose/names_test.go

@@ -33,6 +33,16 @@ func TestTheBusNamesAgree(t *testing.T) {
 	if (Bucket{}).MaxBytes() != -1 || (Bucket{MaxMiB: 2}).MaxBytes() != 2<<20 {
 		t.Fatal("a bucket's cap is not its max-mib in bytes")
 	}
+	// Design 46 7-approval-mark §5: a stream's local event pattern as the bus spells it.
+	for local, wire := range map[string]string{"mail.**": "mail.>", "mail.*.message": "mail.*.message", "sent": "sent"} {
+		if got := WirePattern(local); got != wire {
+			t.Errorf("WirePattern(%q) = %q, want %q", local, got, wire)
+		}
+	}
+	// Design 46 7-approval-mark §13: a per-machine state reaches its machine's key and the keys below it, no other machine's.
+	if got := PerMachineKeys("ace"); len(got) != 2 || got[0] != "ace" || got[1] != "ace.>" {
+		t.Errorf("a per-machine state reaches %v on ace", got)
+	}
 	// A seat's family is the shared events stream filtered to its subjects: a definition says the stream's age.
 	for _, st := range MeshStreams() {
 		if st.Name == EventsStream && int64(st.MaxAge) != seatdef.SharedEventsMaxAgeDays*24*60*60 {

go/buscompose/nats.go

@@ -163,8 +163,8 @@ type Principal struct {
 	// instances and read by whoever declares it.
 	State []string
 	Reads []string
-	// PerMachine is the local names of its state keyed by machine, reaching the key named for Node and
-	// no other; KeyedReads the keys of others' state it reads one key at a time (novox/hq ADR 0260).
+	// PerMachine is the local names of its state keyed by machine, reaching the keys of Node (PerMachineKeys) and
+	// no other machine's; KeyedReads the keys of others' state it reads one key at a time (novox/hq ADR 0260).
 	PerMachine []string
 	KeyedReads []KeyedRead
 	// Logs is the local names of the logs this principal's module keeps (novox/hq ADR 0297).

go/buscompose/state.go

@@ -18,8 +18,8 @@ type Bucket struct {
 	History int
 	// TTLSeconds is how long a value lives; zero is until replaced or deleted.
 	TTLSeconds int
-	// PerMachine says each machine's instance writes only the key named for its machine (novox/hq ADR
-	// 0260), and is granted that key and no other.
+	// PerMachine says each machine's instance writes only the keys of its machine (novox/hq ADR 0260; design 46
+	// 7-approval-mark §13): the key named for its machine and the keys below it, PerMachineKeys, and no other machine's.
 	PerMachine bool
 	// KeyTTL says the bucket allows a time to live per key (novox/hq ADR 0433 §1): its owner writes each key with its
 	// own, and the server writes a delete marker, kept KeyTTLMarkerTTL, when it ends.
@@ -36,6 +36,11 @@ func (b Bucket) MaxBytes() int64 {
 	return int64(b.MaxMiB) * 1024 * 1024
 }
 
+// PerMachineKeys are the keys a machine's instance of a per-machine state reaches (design 46 7-approval-mark §13): the key
+// named for its machine, as every module's per-machine key keeps its form, and the keys below it, `<node>.>`; no other
+// machine's. A membership's per-machine state (membership.StateIssued's Key) reaches the same.
+func PerMachineKeys(node string) []string { return []string{node, node + ".>"} }
+
 // BucketName is the bucket a module's state lives in: the module and the local name joined by an
 // underscore, which neither may contain, so two modules can never derive one bucket.
 func BucketName(module, name string) string { return module + "_" + name }

go/membership/membership.go

@@ -112,7 +112,8 @@ type SeatServed struct {
 }
 
 // StateIssued is one bucket an assignment may reach, by the name its module uses for it (novox/hq ADR 0201).
-// Key, when set, is the one key it may reach (novox/hq ADR 0260): this machine's.
+// Key, when set, names the machine whose keys it may reach (novox/hq ADR 0260; design 46 7-approval-mark §13): that key and the
+// keys below it (buscompose.PerMachineKeys), no other machine's.
 //
 // PerNode says the state is kept one bucket per node (novox/hq ADR 0593 §6: `composed-<node>`): Bucket is then the
 // buckets' prefix, each bucket the prefix and a node's name, and a key's first part names its node and so its bucket.