succd: split out http server, daemon state, daemon controller

This improves the structure of the code, separating the data/control
interface out and then implementing the http interface as a user of this
interface.

succbone/succd/http.go

@@ -15,6 +15,10 @@ import (
 	"k8s.io/klog"
 )
 
+type httpServer struct {
+	d daemonController
+}
+
 var (
 	//go:embed index.html
 	templateIndexText string
@@ -23,7 +27,7 @@ var (
 	favicon []byte
 )
 
-func (d *daemon) httpFavicon(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewFavicon(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "image/png")
 	w.Write(favicon)
 }
@@ -96,12 +100,10 @@ type apiData struct {
 // apiData returns the user data model for the current state of the system. If
 // skipSystem is set, the System subset is ignored (saves system load, and is
 // not being served via websockets).
-func (d *daemon) apiData(skipSystem bool) *apiData {
+func (s *httpServer) apiData(skipSystem bool) *apiData {
-	volts, mbar := d.pirani()
+	state := s.d.snapshot()
-	rp := d.rpGet()
+	volts, mbar := state.pirani()
-	dp := d.dpGet()
+	rough, high := state.vacuumStatus()
-	rough, high := d.vacuumStatusGet()
-	safety := d.safetyStatusGet()
 
 	var hostname, load string
 	var err error
@@ -120,13 +122,13 @@ func (d *daemon) apiData(skipSystem bool) *apiData {
 	}
 
 	ad := apiData{}
-	ad.Safety.Failsafe = safety.failsafe
+	ad.Safety.Failsafe = state.safety.failsafe
-	ad.Safety.HighPressure = safety.highPressure
+	ad.Safety.HighPressure = state.safety.highPressure
 	ad.Pirani.Volts = formatVolts(volts)
 	ad.Pirani.Mbar = formatMbar(mbar)
 	ad.Pirani.MbarFloat = mbar
-	ad.Pumps.RPOn = rp
+	ad.Pumps.RPOn = state.rpOn
-	ad.Pumps.DPOn = dp
+	ad.Pumps.DPOn = state.dpOn
 	ad.Feedback.RoughReached = rough
 	ad.Feedback.HighReached = high
 	ad.System.Load = load
@@ -135,20 +137,20 @@ func (d *daemon) apiData(skipSystem bool) *apiData {
 }
 
 // httpIndex is the / view.
-func (d *daemon) httpIndex(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewIndex(w http.ResponseWriter, r *http.Request) {
 	if r.URL.Path != "/" {
 		http.NotFound(w, r)
 		return
 	}
 
-	data := d.apiData(false)
+	data := s.apiData(false)
 	//data.Pirani.Mbar = html.St
 	templateIndex.Execute(w, data)
 }
 
 // httpStream is the websocket clientwards data hose, returning a 10Hz update
 // stream of pressure/voltage.
-func (d *daemon) httpStream(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewStream(w http.ResponseWriter, r *http.Request) {
 	c, err := websocket.Accept(w, r, nil)
 	if err != nil {
 		return
@@ -165,7 +167,7 @@ func (d *daemon) httpStream(w http.ResponseWriter, r *http.Request) {
 			c.Close(websocket.StatusNormalClosure, "")
 			return
 		case <-t.C:
-			v := d.apiData(true)
+			v := s.apiData(true)
 			if err := wsjson.Write(ctx, c, v); err != nil {
 				klog.Errorf("Websocket write failed: %v", err)
 				return
@@ -175,39 +177,54 @@ func (d *daemon) httpStream(w http.ResponseWriter, r *http.Request) {
 }
 
 // httpMetrics serves minimalistic Prometheus-compatible metrics.
-func (d *daemon) httpMetrics(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewMetrics(w http.ResponseWriter, r *http.Request) {
 	// TODO(q3k): also serve Go stuff using the actual Prometheus metrics client
 	// library.
-	_, mbar := d.pirani()
+	// TODO(q3k): serve the rest of the data model
+	state := s.d.snapshot()
+	_, mbar := state.pirani()
 	fmt.Fprintf(w, "# HELP sem_pressure_mbar Pressure in the SEM chamber, in millibar\n")
 	fmt.Fprintf(w, "# TYPE sem_pressure_mbar gauge\n")
 	fmt.Fprintf(w, "sem_pressure_mbar %f\n", mbar)
 }
 
-func (d *daemon) httpRoughingPumpEnable(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewRoughingPumpEnable(w http.ResponseWriter, r *http.Request) {
-	d.rpSet(true)
+	s.d.rpSet(true)
 	fmt.Fprintf(w, "succ on\n")
 }
 
-func (d *daemon) httpRoughingPumpDisable(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewRoughingPumpDisable(w http.ResponseWriter, r *http.Request) {
-	d.rpSet(false)
+	s.d.rpSet(false)
 	fmt.Fprintf(w, "succ off\n")
 }
 
-func (d *daemon) httpDiffusionPumpEnable(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewDiffusionPumpEnable(w http.ResponseWriter, r *http.Request) {
-	d.dpSet(true)
+	s.d.dpSet(true)
 	fmt.Fprintf(w, "deep succ on\n")
 }
 
-func (d *daemon) httpDiffusionPumpDisable(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewDiffusionPumpDisable(w http.ResponseWriter, r *http.Request) {
-	d.dpSet(false)
+	s.d.dpSet(false)
 	fmt.Fprintf(w, "deep succ off\n")
 }
 
-func (d *daemon) httpButtonPumpDown(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewButtonPumpDown(w http.ResponseWriter, r *http.Request) {
-	d.pumpDownPress()
+	s.d.pumpDownPress()
 }
 
-func (d *daemon) httpButtonVent(w http.ResponseWriter, r *http.Request) {
+func (s *httpServer) viewButtonVent(w http.ResponseWriter, r *http.Request) {
-	d.ventPress()
+	s.d.ventPress()
+}
+
+func (s *httpServer) setupViews() {
+	http.HandleFunc("/", s.viewIndex)
+	http.HandleFunc("/favicon.png", s.viewFavicon)
+	http.HandleFunc("/stream", s.viewStream)
+	http.HandleFunc("/metrics", s.viewMetrics)
+	http.HandleFunc("/button/vent", s.viewButtonVent)
+	http.HandleFunc("/button/pumpdown", s.viewButtonPumpDown)
+	http.HandleFunc("/rp/on", s.viewRoughingPumpEnable)
+	http.HandleFunc("/rp/off", s.viewRoughingPumpDisable)
+	http.HandleFunc("/dp/on", s.viewDiffusionPumpEnable)
+	http.HandleFunc("/dp/off", s.viewDiffusionPumpDisable)
 }

succbone/succd/main.go

@@ -26,9 +26,9 @@ func main() {
 
 	ctx, _ := signal.NotifyContext(context.Background(), os.Interrupt)
 
-	d := daemon{
+	d := daemon{}
-		rpOn: true,
+	d.daemonState.rpOn = true
-	}
+
 	d.aboveRough.threshold = float64(flagPressureThresholdRough)
 	d.aboveHigh.threshold = float64(flagPressureThresholdHigh)
 	if flagFake {
@@ -65,16 +65,10 @@ func main() {
 		}
 	}
 
-	http.HandleFunc("/", d.httpIndex)
+	httpServer := httpServer{
-	http.HandleFunc("/favicon.png", d.httpFavicon)
+		d: &d,
-	http.HandleFunc("/stream", d.httpStream)
+	}
-	http.HandleFunc("/metrics", d.httpMetrics)
+	httpServer.setupViews()
-	http.HandleFunc("/button/vent", d.httpButtonVent)
-	http.HandleFunc("/button/pumpdown", d.httpButtonPumpDown)
-	http.HandleFunc("/rp/on", d.httpRoughingPumpEnable)
-	http.HandleFunc("/rp/off", d.httpRoughingPumpDisable)
-	http.HandleFunc("/dp/on", d.httpDiffusionPumpEnable)
-	http.HandleFunc("/dp/off", d.httpDiffusionPumpDisable)
 
 	klog.Infof("Listening for HTTP at %s", flagListenHTTP)
 	go func() {

succbone/succd/process.go

@@ -4,21 +4,18 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"math"
 	"sync"
 	"time"
 
 	"k8s.io/klog"
 )
 
-// daemon is the main state of the succdaemon.
+// daemon is the main service of the succdaemon.
 type daemon struct {
 	// adcPirani is the adc implementation returning the voltage of the Pfeiffer
 	// Pirani gauge.
 	adcPirani adc
 
-	safety safetyStatus
-
 	gpioDiffusionPump gpio
 	gpioRoughingPump  gpio
 	gpioBtnPumpDown   gpio
@@ -26,27 +23,9 @@ type daemon struct {
 	gpioBelowRough    gpio
 	gpioBelowHigh     gpio
 
-	// mu guards state variables below.
+	// mu guards the state below.
 	mu sync.RWMutex
-	// adcPiraniVolts is a moving window of read ADC values, used to calculate a
+	daemonState
-	// moving average.
-	adcPiraniVolts []float32
-	rpOn           bool
-	dpOn           bool
-
-	vent       momentaryOutput
-	pumpdown   momentaryOutput
-	aboveRough thresholdOutput
-	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.
@@ -127,7 +106,7 @@ func (d *daemon) processOnce(_ context.Context) error {
 	d.pumpdown.process()
 	d.vent.process()
 
-	_, mbar := d.piraniUnlocked()
+	_, mbar := d.daemonState.pirani()
 	d.aboveRough.process(float64(mbar))
 	d.aboveHigh.process(float64(mbar))
 
@@ -201,116 +180,3 @@ func (d *daemon) processOnce(_ context.Context) error {
 
 	return nil
 }
-
-type piraniDetection uint
-
-const (
-	// piraniDetectionUnknown means the system isn't yet sure whether the pirani
-	// gauge is connected.
-	piraniDetectionUnknown piraniDetection = iota
-	// piraniDetectionConnected means the system assumes the pirani gauge is
-	// connected.
-	piraniDetectionConnected = iota
-	// piraniDetectionDisconnected means the system assumes the pirani gauge is
-	// disconnected.
-	piraniDetectionDisconnected = iota
-)
-
-// piraniDetection guesses whether the pirani gauge is connected.
-func (d *daemon) piraniDetection() piraniDetection {
-	if len(d.adcPiraniVolts) < 3 {
-		return piraniDetectionUnknown
-	}
-	volts := float32(0.0)
-	for _, v := range d.adcPiraniVolts[len(d.adcPiraniVolts)-3:] {
-		volts += v
-	}
-	volts /= 3.0
-
-	bar := math.Pow(10.0, float64(volts)-8.5)
-	mbar := float32(bar * 1000.0)
-
-	if mbar < 4e-6 {
-		return piraniDetectionDisconnected
-	}
-	return piraniDetectionConnected
-}
-
-// pirani returns the Pirani gauge voltage and pressure.
-func (d *daemon) pirani() (volts float32, mbar float32) {
-	d.mu.RLock()
-	volts, mbar = d.piraniUnlocked()
-	d.mu.RUnlock()
-	return
-}
-
-func (d *daemon) piraniUnlocked() (volts float32, mbar float32) {
-	volts = 0.0
-	for _, v := range d.adcPiraniVolts {
-		volts += v
-	}
-	if len(d.adcPiraniVolts) != 0 {
-		volts /= float32(len(d.adcPiraniVolts))
-	}
-
-	// Per Pirani probe docs.
-	bar := math.Pow(10.0, float64(volts)-8.5)
-	mbar = float32(bar * 1000.0)
-	return
-}
-
-// rpSet enables/disables the roughing pump.
-func (d *daemon) rpSet(state bool) {
-	d.mu.Lock()
-	defer d.mu.Unlock()
-	d.rpOn = state
-}
-
-// rpGet returns whether the roughing pump is enabled/disabled.
-func (d *daemon) rpGet() bool {
-	d.mu.RLock()
-	defer d.mu.RUnlock()
-	return d.rpOn
-}
-
-// dpSet enables/disables the diffusion pump.
-func (d *daemon) dpSet(state bool) {
-	d.mu.Lock()
-	defer d.mu.Unlock()
-	d.dpOn = state
-}
-
-// dpGet returns whether the diffusion pump is enabled/disabled.
-func (d *daemon) dpGet() bool {
-	d.mu.RLock()
-	defer d.mu.RUnlock()
-	return d.dpOn
-}
-
-func (d *daemon) vacuumStatusGet() (rough, high bool) {
-	d.mu.RLock()
-	defer d.mu.RUnlock()
-	rough = !d.aboveRough.output
-	high = !d.aboveHigh.output
-	return
-}
-
-func (d *daemon) safetyStatusGet() safetyStatus {
-	d.mu.RLock()
-	defer d.mu.RUnlock()
-	return d.safety
-}
-
-// pumpDownPressed toggles the pump down relay for 500ms.
-func (d *daemon) pumpDownPress() {
-	d.mu.Lock()
-	defer d.mu.Unlock()
-	d.pumpdown.trigger()
-}
-
-// ventPress toggles the vent relay for 500ms.
-func (d *daemon) ventPress() {
-	d.mu.Lock()
-	defer d.mu.Unlock()
-	d.vent.trigger()
-}

succbone/succd/process_controller.go

@@ -0,0 +1,49 @@
+package main
+
+// daemonController is the control/data interface passed on to external system
+// controllers, eg. the web interface.
+//
+// This is a subset of daemon functions limited to a safe, explicit subset.
+type daemonController interface {
+	// snapshot returns an internally consistent copy of the daemon state.
+	snapshot() *daemonState
+	// rpSet enables/disables the roughing pump.
+	rpSet(bool)
+	// dpSet enables/disables the diffusion pump.
+	dpSet(bool)
+	// pumpDownPress simulates a pumpdown button press.
+	pumpDownPress()
+	// ventPRess simulates a vent button press.
+	ventPress()
+}
+
+func (d *daemon) snapshot() *daemonState {
+	d.mu.RLock()
+	ds := d.daemonState
+	d.mu.RUnlock()
+	return &ds
+}
+
+func (d *daemon) rpSet(state bool) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.rpOn = state
+}
+
+func (d *daemon) dpSet(state bool) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.dpOn = state
+}
+
+func (d *daemon) pumpDownPress() {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.pumpdown.trigger()
+}
+
+func (d *daemon) ventPress() {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.vent.trigger()
+}

succbone/succd/process_state.go

@@ -0,0 +1,84 @@
+package main
+
+import "math"
+
+// daemonState contains all the state of the daemon. A copy of it can be
+// requested for consumers, eg. the web view.
+type daemonState struct {
+	safety safetyStatus
+
+	// adcPiraniVolts is a moving window of read ADC values, used to calculate a
+	// moving average.
+	adcPiraniVolts []float32
+	rpOn           bool
+	dpOn           bool
+
+	vent       momentaryOutput
+	pumpdown   momentaryOutput
+	aboveRough thresholdOutput
+	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
+}
+
+type piraniDetection uint
+
+const (
+	// piraniDetectionUnknown means the system isn't yet sure whether the pirani
+	// gauge is connected.
+	piraniDetectionUnknown piraniDetection = iota
+	// piraniDetectionConnected means the system assumes the pirani gauge is
+	// connected.
+	piraniDetectionConnected = iota
+	// piraniDetectionDisconnected means the system assumes the pirani gauge is
+	// disconnected.
+	piraniDetectionDisconnected = iota
+)
+
+// piraniDetection guesses whether the pirani gauge is connected.
+func (d *daemonState) piraniDetection() piraniDetection {
+	if len(d.adcPiraniVolts) < 3 {
+		return piraniDetectionUnknown
+	}
+	volts := float32(0.0)
+	for _, v := range d.adcPiraniVolts[len(d.adcPiraniVolts)-3:] {
+		volts += v
+	}
+	volts /= 3.0
+
+	bar := math.Pow(10.0, float64(volts)-8.5)
+	mbar := float32(bar * 1000.0)
+
+	if mbar < 4e-6 {
+		return piraniDetectionDisconnected
+	}
+	return piraniDetectionConnected
+}
+
+func (d *daemonState) pirani() (volts float32, mbar float32) {
+	volts = 0.0
+	for _, v := range d.adcPiraniVolts {
+		volts += v
+	}
+	if len(d.adcPiraniVolts) != 0 {
+		volts /= float32(len(d.adcPiraniVolts))
+	}
+
+	// Per Pirani probe docs.
+	bar := math.Pow(10.0, float64(volts)-8.5)
+	mbar = float32(bar * 1000.0)
+	return
+}
+
+func (d *daemonState) vacuumStatus() (rough, high bool) {
+	rough = !d.aboveRough.output
+	high = !d.aboveHigh.output
+	return
+}