Add ignoreNextMessages: stay connected but leave messages unanswered

README.md

@@ -8,7 +8,7 @@ Fake pod implementation
 
 * This version also mimics a behavior we see in some DASH pods where the pod disconnects every 3 minutes; this can be used with iOS hooks to make a heartbeat to run Loop in situations where a BLE CGM is not available. 
 
-* It serves a control panel at http://<host>:8080/ (`-api` changes the address): the pod's reservoir, delivery, age, alerts and fault, with controls to set the reservoir and pod age, raise alerts, trigger or clear a fault, and crash on the next command to test unacknowledged commands. The panel drives a JSON API: `GET /status`, and `POST /command` with `{"command": "changeReservoir", "value": 45}` (also `setActiveTime` in minutes, `setAlerts` as a slot mask, `setFault` with a fault code, 0 to clear, and `crashNextCommand` with `"beforeProcessing": true|false`).
+* It serves a control panel at http://<host>:8080/ (`-api` changes the address): the pod's reservoir, delivery, age, alerts and fault, with controls to set the reservoir and pod age, raise alerts, trigger or clear a fault, and crash on the next command to test unacknowledged commands. The panel drives a JSON API: `GET /status`, and `POST /command` with `{"command": "changeReservoir", "value": 45}` (also `setActiveTime` in minutes, `setAlerts` as a slot mask, `setFault` with a fault code, 0 to clear, `crashNextCommand` with `"beforeProcessing": true|false`, and `ignoreNextMessages` with a count, which keeps the link up but leaves that many messages unanswered, as a pod that didn't hear them would).
 
 * The websocket API at `/ws`, used by the separate [NodeJS/React frontend](https://github.com/ps2/pod_simulator_frontend), is still there.
 

pkg/api/server.go

@@ -173,6 +173,11 @@ func (s *Server) handleCommand(bytes []byte) error {
 			return err
 		}
 		s.pod.SetActiveTime(int(value))
+	case "ignoreNextMessages":
+		if err := needValue("message count", 0, 100); err != nil {
+			return err
+		}
+		s.pod.IgnoreNextMessages(int(value))
 	case "crashNextCommand":
 		beforeProcessing, ok := msg["beforeProcessing"].(bool)
 		if !ok {

pkg/pod/pod.go

@@ -47,6 +47,7 @@ type Pod struct {
 // Once one of these are set, the next command will crash the executable.
 var crashBeforeProcessingCommand bool
 var crashAfterProcessingCommand bool
+var ignoreMessages int
 
 func New(ble *bluetooth.Ble, state *PODState) *Pod {
 	ret := &Pod{
@@ -338,6 +339,17 @@ func (p *Pod) CommandLoop(pMsg PodMsgBody) {
 		}
 		log.Tracef("pkg pod; got command message: %s", spew.Sdump(msg))
 
+		p.mtx.Lock()
+		ignore := ignoreMessages > 0
+		if ignore {
+			ignoreMessages--
+		}
+		p.mtx.Unlock()
+		if ignore {
+			log.Infof("pkg pod; ignoring message seq %d (ignoreNextMessages)", msg.SequenceNumber)
+			continue
+		}
+
 		if msg.SequenceNumber == lastMsgSeq {
 			// this is a retry because we did not answer yet
 			// ignore duplicate commands/mesages
@@ -835,6 +847,14 @@ func (p *Pod) SetActiveTime(newVal int) {
 	p.mtx.Unlock()
 }
 
+// IgnoreNextMessages makes the pod stay connected but not answer the next
+// count messages, as a pod that didn't hear them would.
+func (p *Pod) IgnoreNextMessages(count int) {
+	p.mtx.Lock()
+	ignoreMessages = count
+	p.mtx.Unlock()
+}
+
 func (p *Pod) CrashNextCommand(beforeProcessing bool) {
 	p.mtx.Lock()
 	if beforeProcessing {