succd: factor out safety status to separate struct

succbone/succd/http.go

@@ -60,7 +60,7 @@ func (d *daemon) httpIndex(w http.ResponseWriter, r *http.Request) {
 	volts, mbar := d.pirani()
 	rp := d.rpGet()
 	dp := d.dpGet()
-  failsafe, highpressure := d.safetyStatusGet()
+	safety := d.safetyStatusGet()
 
 	loadB, err := os.ReadFile("/proc/loadavg")
 	load := "unknown"
@@ -75,8 +75,8 @@ func (d *daemon) httpIndex(w http.ResponseWriter, r *http.Request) {
 	}
 
 	templateIndex.Execute(w, map[string]any{
-		"failsafe":     failsafe,
+		"failsafe":     safety.failsafe,
-		"highpressure": highpressure,
+		"highpressure": safety.highPressure,
 		"volts":        formatVolts(volts),
 		"mbar":         formatMbar(mbar),
 		"rp":           rp,
@@ -110,7 +110,7 @@ func (d *daemon) httpStream(w http.ResponseWriter, r *http.Request) {
 			rp := d.rpGet()
 			dp := d.dpGet()
 			rough, high := d.vacuumStatusGet()
-      failsafe, highpressure := d.safetyStatusGet()
+			safety := d.safetyStatusGet()
 			v := struct {
 				Failsafe     bool
 				HighPressure bool
@@ -122,8 +122,8 @@ func (d *daemon) httpStream(w http.ResponseWriter, r *http.Request) {
 				RoughReached bool
 				HighReached  bool
 			}{
-        Failsafe:     failsafe,
+				Failsafe:     safety.failsafe,
-        HighPressure: highpressure,
+				HighPressure: safety.highPressure,
 				Volts:        formatVolts(volts),
 				Mbar:         string(formatMbar(mbar)),
 				MbarFloat:    mbar,

succbone/succd/process.go

@@ -17,8 +17,7 @@ type daemon struct {
 	// Pirani gauge.
 	adcPirani adc
 
-	failsafe     bool
+	safety safetyStatus
-	highPressure bool
 
 	gpioDiffusionPump gpio
 	gpioRoughingPump  gpio
@@ -41,6 +40,15 @@ type daemon struct {
 	aboveHigh  thresholdOutput
 }
 
+type safetyStatus struct {
+	// failsafe mode is enabled when the pirani gauge appears to be
+	// disconnected, and is disabled only when an atmosphere is read.
+	failsafe bool
+	// highPressure mode is enabled when the pressure reading is above 1e-1
+	// mbar, locking out the diffusion pump from being enabled.
+	highPressure bool
+}
+
 // momentaryOutput is an output that can be triggered for 500ms.
 type momentaryOutput struct {
 	// output of the block.
@@ -128,38 +136,38 @@ func (d *daemon) processOnce(_ context.Context) error {
 	// samples are still being captured.
 	if d.piraniDetection() == piraniDetectionDisconnected {
 		// Unrealistic result, Pirani probe probably disconnected. Failsafe mode.
-		if !d.failsafe {
+		if !d.safety.failsafe {
-			d.failsafe = true
+			d.safety.failsafe = true
 			klog.Errorf("Pirani probe seems disconnected; enabling failsafe mode")
 		}
 	} else {
-		if d.failsafe {
+		if d.safety.failsafe {
 			if mbar >= 1e2 {
-				d.failsafe = false
+				d.safety.failsafe = false
 				klog.Infof("Values are plausible again; quitting failsafe mode")
 			}
 		}
 	}
 
 	if mbar >= 1e-1 {
-		if !d.highPressure {
+		if !d.safety.highPressure {
-			d.highPressure = true
+			d.safety.highPressure = true
 			klog.Errorf("Pressure is too high; enabling diffusion pump lockout")
 		}
 	} else {
-		if d.highPressure {
+		if d.safety.highPressure {
-			d.highPressure = false
+			d.safety.highPressure = false
 			klog.Infof("Pressure is low enough for diffusion pump operation; quitting diffusion pump lockout")
 		}
 	}
 
-	if d.failsafe {
+	if d.safety.failsafe {
 		d.aboveRough.output = true
 		d.aboveHigh.output = true
 		d.dpOn = false
 	}
 
-	if d.highPressure {
+	if d.safety.highPressure {
 		d.dpOn = false
 	}
 
@@ -287,12 +295,10 @@ func (d *daemon) vacuumStatusGet() (rough, high bool) {
 	return
 }
 
-func (d *daemon) safetyStatusGet() (failsafe, highPressure bool) {
+func (d *daemon) safetyStatusGet() safetyStatus {
 	d.mu.RLock()
 	defer d.mu.RUnlock()
-	failsafe = d.failsafe
+	return d.safety
-	highPressure = d.highPressure
-	return
 }
 
 // pumpDownPressed toggles the pump down relay for 500ms.