Feature 57 (config and provisioning): release mesh-tools (the provider's StateBus, the SDK pin, templates), reviewed

node-tools/internal/launch/launch.go

@@ -83,6 +83,11 @@ type Bus interface {
 	// `take` and `answer` bind once and hand each message or proof on through handOn, to whichever child
 	// of the module asked last — a restarted child asks again as its code runs again.
 	Seat(verb string, params json.RawMessage, handOn func(method string, params any) (json.RawMessage, error)) (json.RawMessage, error)
+	// Provision answers a bundle's `get` of one of its module's values at runtime, and ProvisionWatch hands deliver
+	// that value now and each change after, as the module whose bundle asks and never a module the bundle names
+	// (novox/hq ADR 0349 §14, ADR 0370 §4): its config, and its bindings' values that are not secret.
+	Provision(verb string, params json.RawMessage) (json.RawMessage, error)
+	ProvisionWatch(params json.RawMessage, deliver func(change json.RawMessage) error) (stop func(), err error)
 }
 
 // EventTimeout bounds how long a bundle has to handle one event before it is offered again.
@@ -307,6 +312,30 @@ func Start(module, entry string, env []string, mesh Bus, logf func(string, ...an
 							if answered, err = mesh.Log(strings.TrimPrefix(m.Method, "mesh/log."), m.Params); err == nil {
 								result = answered
 							}
+						case "mesh/provision.get":
+							var answered json.RawMessage
+							if answered, err = mesh.Provision("get", m.Params); err == nil {
+								result = answered
+							}
+						case "mesh/provision.watch":
+							// As a state's watch: each change asked of this child in order, naming the watch by the
+							// id the child asked it with, and answered once the current value is handed over.
+							var stop func()
+							watch := m.ID
+							stop, err = mesh.ProvisionWatch(m.Params, func(change json.RawMessage) error {
+								_, err := c.ask(module, "mesh/provision", map[string]any{"watch": watch, "change": change}, EventTimeout)
+								return err
+							})
+							if err == nil {
+								c.mu.Lock()
+								if c.why != nil {
+									c.mu.Unlock()
+									stop()
+								} else {
+									c.watches = append(c.watches, stop)
+									c.mu.Unlock()
+								}
+							}
 						case "mesh/state.watch":
 							// Each change is asked of this child, in order, naming the watch it is for by
 							// the id the child asked it with — two watches of one state are two handlers;