New direction?

cmd/fermentord/config.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"git.joco.dk/sng/fermentord/internal/controllers"
+	"git.joco.dk/sng/fermentord/pkg/temperature"
+	"github.com/getsentry/sentry-go"
+	"github.com/rs/zerolog/log"
+	"github.com/spf13/viper"
+)
+
+type configuration struct {
+	controllers.ControllerConfig
+
+	HTTP struct {
+		Port int16 `mapstructure:"port"`
+	} `mapstructure:"http"`
+
+	DB struct {
+		Local struct {
+			DSN string `mapstructure:"dsn"`
+		} `mapstructure:"local"`
+	} `mapstructure:"db"`
+}
+
+func loadConfiguration() *configuration {
+	config := &configuration{}
+
+	viper.SetDefault("pid.kp", 2.0)
+	viper.SetDefault("pid.ki", 0.0001)
+	viper.SetDefault("pid.kd", 2.0)
+	viper.SetDefault("db.local.dsn", "/var/lib/fermentord/local.db")
+	viper.SetDefault("http.port", 8000)
+	viper.SetDefault("db.local.dsn", "./fermentord.db")
+
+	viper.AllowEmptyEnv(true)
+	viper.AutomaticEnv()
+	viper.AddConfigPath("/etc")
+	viper.SetConfigName("fermentord")
+	viper.SetConfigType("hcl")
+
+	if err := viper.ReadInConfig(); err != nil {
+		log.Debug().
+			Err(err).
+			Msg("Error loading configuration")
+	}
+
+	if err := viper.Unmarshal(&config); err != nil {
+		sentry.CaptureException(err)
+		log.Fatal().
+			Err(err).
+			Msg("Error unmarshalling configuration")
+	}
+
+	return config
+}
+
+func reloadConfiguration(config *configuration, ctrl *controllers.ChamberController) {
+	temperature.ConfigUpdates <- []string{
+		config.Sensor.Ambient,
+		config.Sensor.Chamber,
+		config.Sensor.Wort,
+	}
+
+	ctrl.ConfigUpdates <- config.ControllerConfig
+}

cmd/fermentord/config.hcl

@@ -0,0 +1,27 @@
+// fermentord
+
+fermentation_temp = 15.0
+delta_temp = 0.5
+
+sensors {
+  wort = "asdf"
+  chamber = "sldkfj"
+  ambient = "skdjf"
+}
+
+limits {
+  min_chamber_temp = 5
+  min_cooler_runtime_secs = 300
+  max_cooler_runtime_secs = 86400
+  min_cooler_cooldown_secs = 300
+}
+
+pid {
+  kp = 2.0
+  ki = 0.0001
+  kd = 2.0
+}
+
+db "local" {
+  dsn = "/var/lib/fermentord/local.db"
+}

cmd/fermentord/conversion.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"git.joco.dk/sng/fermentord/internal/controllers"
+	"git.joco.dk/sng/fermentord/internal/dal"
+)
+
+func convertChamberState(state controllers.ChamberState) dal.ChamberState {
+	switch state {
+	case controllers.ChamberStateIdle:
+		return dal.ChamberStateIdle
+
+	case controllers.ChamberStateCooling:
+		return dal.ChamberStateCooling
+
+	case controllers.ChamberStateHeating:
+		return dal.ChamberStateHeating
+
+	default:
+		return dal.ChamberStateIdle
+	}
+}

cmd/fermentord/db.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"sync"
+	"time"
+
+	"git.joco.dk/sng/fermentord/internal/controllers"
+	"git.joco.dk/sng/fermentord/internal/dal"
+	"git.joco.dk/sng/fermentord/pkg/temperature"
+	"github.com/getsentry/sentry-go"
+	"github.com/rs/zerolog/log"
+)
+
+func migrateDB(config configuration) {
+	migrator, err := dal.NewMigrator(config.DB.Local.DSN)
+	if err != nil {
+		sentry.CaptureException(err)
+		log.Fatal().Err(err).Msg("Error initializing DB migrations")
+	}
+	migrator.Up()
+	serr, dberr := migrator.Close()
+	if serr != nil {
+		sentry.CaptureException(serr)
+		log.Fatal().Err(serr).Msg("DB migration source error")
+	}
+	if dberr != nil {
+		sentry.CaptureException(dberr)
+		log.Fatal().Err(dberr).Msg("DB migration database error")
+	}
+}
+
+func persistData(ctx context.Context, wg *sync.WaitGroup, db *dal.DAL, chState <-chan controllers.ChamberState, chTemp <-chan temperature.TemperatureReading) {
+	defer wg.Done()
+
+	for {
+		select {
+		case state, ok := <-chState:
+			if !ok {
+				break
+			}
+
+			ctxTo, cancel := context.WithTimeout(ctx, 10*time.Second)
+			err := db.InReadWriteTransaction(ctxTo, func(tx *sql.Tx) error {
+				return dal.SaveChamberState(ctxTo, tx, convertChamberState(state))
+			})
+			if err != nil {
+				sentry.CaptureException(err)
+				log.Error().Err(err).Msg("Error persisting state change")
+			}
+			cancel()
+
+		case t, ok := <-chTemp:
+			if !ok {
+				break
+			}
+
+			ctxTo, cancel := context.WithTimeout(ctx, 10*time.Second)
+			err := db.InReadWriteTransaction(ctxTo, func(tx *sql.Tx) error {
+				return dal.SaveTemperatureReading(ctx, tx, t.Time, t.Sensor, t.MilliDegrees)
+			})
+			if err != nil {
+				sentry.CaptureException(err)
+				log.Error().Err(err).Msg("Error persisting temperature reading")
+			}
+			cancel()
+
+		case <-ctx.Done():
+			return
+		}
+	}
+}

cmd/fermentord/main.go

@@ -2,11 +2,9 @@ package main
 
 import (
 	"context"
+	"fmt"
 	"net/http"
-	"os"
-	"os/signal"
 	"sync"
-	"syscall"
 	"time"
 
 	"git.joco.dk/sng/fermentord/internal/api"
@@ -14,6 +12,7 @@ import (
 	"git.joco.dk/sng/fermentord/internal/dal"
 	"git.joco.dk/sng/fermentord/internal/hw"
 	"git.joco.dk/sng/fermentord/internal/metrics"
+	"git.joco.dk/sng/fermentord/pkg/daemon"
 	"git.joco.dk/sng/fermentord/pkg/temperature"
 	"github.com/fsnotify/fsnotify"
 	"github.com/getsentry/sentry-go"
@@ -22,93 +21,70 @@ import (
 	"github.com/spf13/viper"
 )
 
-type configuration struct {
-	Db struct {
-		Dsn string `mapstructure:"dsn"`
-	} `mapstructure:"db"`
-	Temperature struct {
-		WortSensor    string `mapstructure:"wort_sensor"`
-		ChamberSensor string `mapstructure:"chamber_sensor"`
-		AmbientSensor string `mapstructure:"ambient_sensor"`
-	} `mapstructure:"temperature"`
-	Hysteresis controllers.Config `mapstructure:"hysteresis"`
-}
-
-var (
-	config     configuration
-	ctx        context.Context
-	wg         *sync.WaitGroup
-	hysteresis *controllers.Hysteresis
-	gpio       *hw.Gpio
-)
-
-func bool2ChamberState(state bool) dal.ChamberState {
-	if state {
-		return dal.ChamberStateCooling
-	}
-	return dal.ChamberStateIdle
-}
-
-func mainLoop(db *dal.DAL, wg *sync.WaitGroup) {
+func mainLoop(ctx context.Context, wg *sync.WaitGroup, db *dal.DAL, config *configuration) {
 	defer wg.Done()
 
+	temperature.Initialize()
+
+	// Controller
+	chCtrlTemp := make(chan temperature.TemperatureReading, 10)
+	defer close(chCtrlTemp)
+	ctrl := controllers.NewChamberController("Chamber 1", config.ControllerConfig, chCtrlTemp)
+
+	// Configuration reload
+	viper.OnConfigChange(func(in fsnotify.Event) {
+		reloadConfiguration(config, ctrl)
+	})
+	viper.WatchConfig()
+	reloadConfiguration(config, ctrl)
+
+	gpio, err := hw.NewGpio()
+	if err != nil {
+		sentry.CaptureException(err)
+		log.Fatal().
+			Err(err).
+			Msg("Error initializing GPIO")
+	}
+	defer gpio.Close()
+
+	chDbTemp := make(chan temperature.TemperatureReading, 10)
+	chDbState := make(chan controllers.ChamberState, 10)
+	defer close(chDbTemp)
+	defer close(chDbState)
+
+	wg.Add(3)
+	go persistData(ctx, wg, db, chDbState, chDbTemp)
+	go ctrl.Run(ctx, wg)
+	go temperature.PollSensors(ctx, wg, 1*time.Second)
+
 	for {
 		select {
+		case reading := <-temperature.C:
+			chCtrlTemp <- reading
+			chDbTemp <- reading
+
+		case state := <-ctrl.C:
+			switch state {
+			case controllers.ChamberStateIdle:
+				metrics.State.Set(metrics.MetricStateIdle)
+				gpio.StopCooler()
+				gpio.StopHeater()
+
+			case controllers.ChamberStateCooling:
+				metrics.State.Set(metrics.MetricStateCooling)
+				gpio.StopHeater()
+				gpio.StartCooler()
+
+			case controllers.ChamberStateHeating:
+				metrics.State.Set(metrics.MetricStateHeating)
+				gpio.StopCooler()
+				gpio.StartHeater()
+			}
+
+			chDbState <- state
+
 		case <-ctx.Done():
 			return
-
-		case state := <-hysteresis.C:
-			ctx := context.Background()
-
-			if state {
-				metrics.State.Set(1)
-				//gpio.StartCooler()
-			} else {
-				metrics.State.Set(0)
-				//gpio.StopCooler()
-			}
-
-			dbCtx, cancel := context.WithTimeout(ctx, 10*time.Second)
-			tx, err := db.Begin()
-			if err != nil {
-				sentry.CaptureException(err)
-				log.Error().Err(err).Msg("Failed to start DB transaction")
-			} else {
-				dal.SaveChamberState(dbCtx, tx, bool2ChamberState(state))
-				err = tx.Commit()
-				if err != nil {
-					sentry.CaptureException(err)
-					log.Error().Err(err).Msg("Failed to commit DB transaction")
-				}
-			}
-			cancel()
-
-		case reading := <-temperature.C:
-			ctx := context.Background()
-
-			switch reading.Sensor {
-			case config.Temperature.AmbientSensor:
-				hysteresis.UpdateAmbientTemperature(reading.Degrees())
-
-			case config.Temperature.ChamberSensor:
-				hysteresis.UpdateChamberTemperature(reading.Degrees())
-
-			case config.Temperature.WortSensor:
-				hysteresis.UpdateWortTemperature(reading.Degrees())
-			}
-
-			dbCtx, cancel := context.WithTimeout(ctx, 10*time.Second)
-			tx, err := db.Begin()
-			if err != nil {
-				log.Error().Err(err).Msg("Failed to start DB transaction")
-			} else {
-				dal.SaveTemperatureReading(dbCtx, tx, reading.Sensor, reading.MilliDegrees)
-				err = tx.Commit()
-				if err != nil {
-					log.Error().Err(err).Msg("Failed to commit DB transaction")
-				}
-			}
-			cancel()
 		}
 	}
 }
@@ -120,79 +96,32 @@ func main() {
 		TracesSampleRate: 0.01,
 	})
 	if err != nil {
-		log.Fatal().Err(err).Msg("Failed to initialize Sentry.")
+		log.Fatal().
+			Err(err).
+			Msg("Failed to initialize Sentry.")
 	}
 	defer sentry.Flush(10 * time.Second)
 
 	// Configuration
-	viper.AllowEmptyEnv(true)
-	viper.AutomaticEnv()
-	viper.SetDefault("db.dsn", "./fermentord.db")
-	viper.AddConfigPath("/etc")
-	viper.SetConfigName("fermentord")
-	viper.SetConfigType("hcl")
-	viper.ReadInConfig()
-	viper.Unmarshal(&config)
-
-	ctxb := context.Background()
-	ctx, shutdown := context.WithCancel(ctxb)
-	wg = &sync.WaitGroup{}
-
-	temperature.Initialize(10 * time.Second)
-	hysteresis = controllers.NewHysteresis("Chamber 1")
-
-	reloadConfig := func() {
-		temperature.SetSensors([]string{
-			config.Temperature.AmbientSensor,
-			config.Temperature.ChamberSensor,
-			config.Temperature.WortSensor,
-		})
-		hysteresis.SetConfig(&config.Hysteresis)
-	}
-
-	viper.OnConfigChange(func(in fsnotify.Event) {
-		reloadConfig()
-	})
-	viper.WatchConfig()
-	reloadConfig()
+	config := loadConfiguration()
 
 	// Database
-	migrator, err := dal.NewMigrator(config.Db.Dsn)
-	if err != nil {
-		log.Fatal().Err(err).Msg("Error initializing DB migrations")
-	}
-	migrator.Up()
-	serr, dberr := migrator.Close()
-	if serr != nil {
-		log.Fatal().Err(serr).Msg("DB migration source error")
-	}
-	if dberr != nil {
-		log.Fatal().Err(dberr).Msg("DB migration database error")
-	}
+	migrateDB(*config)
 
 	var db *dal.DAL
-	if db, err := dal.NewDAL(config.Db.Dsn); err != nil {
+	if db, err := dal.NewDAL(config.DB.Local.DSN); err != nil {
+		sentry.CaptureException(err)
 		log.Fatal().Err(err).Msg("Error connecting to DB")
 	} else {
-		db.Initialize()
 		defer db.Close()
 	}
 
-	// GPIO
-	log.Info().Msg("Initializing GPIO")
-	gpio, err := hw.NewGpio()
-	if err != nil {
-		log.Fatal().Err(err).Send()
-	}
-	defer gpio.Close()
-
 	// HTTP
 	mux := http.NewServeMux()
 	srv := &http.Server{
-		Addr:    ":8000",
+		Addr:    fmt.Sprintf(":%v", config.HTTP.Port),
 		Handler: mux,
 	}
-
 	api := api.NewAPI(db)
 
 	// Metrics
@@ -202,31 +131,32 @@ func main() {
 	mux.HandleFunc("/state-changes", api.GetStateChanges)
 
 	// Main
-	wg.Add(2)
-	go temperature.Serve(ctx, wg)
-	go mainLoop(db, wg)
+	ctxb := context.Background()
+	ctx, shutdown := context.WithCancel(ctxb)
+	wg := &sync.WaitGroup{}
+
+	wg.Add(1)
+	go mainLoop(ctx, wg, db, config)
+
 	go srv.ListenAndServe()
 
-	done := make(chan os.Signal, 1)
-	signal.Notify(done, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)
-	<-done
-
-	go func() {
-		ctx, cancel := context.WithTimeout(ctxb, 10*time.Second)
-		defer cancel()
-		err := srv.Shutdown(ctx)
-		if err != nil {
-			log.Error().Err(err).Msg("Error shutting down HTTP server.")
-		}
-	}()
+	daemon.WaitForExitSignal()
 
 	// Initiate graceful shutdown.
+	wg.Add(1)
+	go shutdownHTTP(ctxb, wg, srv)
 	shutdown()
-
-	// Wait for graceful shutdown.
 	wg.Wait()
-
-	// TODO PID for heating
-	// TODO Data export
-	// TODO SQL migrations https://github.com/golang-migrate/migrate/tree/master/database/sqlite
+}
+
+func shutdownHTTP(ctx context.Context, wg *sync.WaitGroup, srv *http.Server) {
+	defer wg.Done()
+	ctx2, cancel := context.WithTimeout(ctx, 10*time.Second)
+	defer cancel()
+	if err := srv.Shutdown(ctx2); err != nil {
+		sentry.CaptureException(err)
+		log.Error().
+			Err(err).
+			Msg("Error shutting down HTTP server.")
+	}
 }

internal/api/http.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"context"
+	"database/sql"
 	"encoding/json"
 	"fmt"
 	"net/http"
@@ -15,7 +16,7 @@ import (
 
 type API struct {
 	db                   *dal.DAL
-	config               *controllers.Config
+	config               *controllers.ControllerConfig
 	configChangeCallback func()
 }
 
@@ -27,15 +28,14 @@ func NewAPI(db *dal.DAL) *API {
 
 func (a *API) HealthCheck(w http.ResponseWriter, r *http.Request) {
 	defer sentry.Recover()
+	ctxb := context.Background()
 
-	tx, err := a.db.Begin()
-	if err != nil {
-		http.Error(w, "Unhealthy", http.StatusServiceUnavailable)
-		return
-	}
-
-	var version string
-	err = tx.QueryRow("SELECT version()").Scan(&version)
+	ctx, cancel := context.WithTimeout(ctxb, 5*time.Second)
+	defer cancel()
+	err := a.db.InReadOnlyTransaction(ctx, func(tx *sql.Tx) error {
+		_, err := tx.Query("SELECT version()")
+		return err
+	})
 	if err != nil {
 		http.Error(w, "Unhealthy", http.StatusServiceUnavailable)
 		return
@@ -57,13 +57,7 @@ func (a *API) GetConfig(w http.ResponseWriter, r *http.Request) {
 
 func (a *API) GetTemperatures(w http.ResponseWriter, r *http.Request) {
 	defer sentry.Recover()
-
-	ctx := context.Background()
-	tx, err := a.db.Begin()
-	defer tx.Rollback()
-	if err != nil {
-		log.Panic().Err(err).Msg("Failed to start DB transaction.")
-	}
+	ctxb := context.Background()
 
 	keys, ok := r.URL.Query()["since"]
 	if !ok || len(keys[0]) < 1 {
@@ -77,30 +71,32 @@ func (a *API) GetTemperatures(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	dbCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
+	ctx, cancel := context.WithTimeout(ctxb, 30*time.Second)
 	defer cancel()
-	readings, err := dal.LoadTemperatureReadingsSince(dbCtx, tx, since)
+	var data []byte
+	err = a.db.InReadOnlyTransaction(ctx, func(tx *sql.Tx) error {
+		readings, err := dal.LoadTemperatureReadingsSince(ctx, tx, since)
+		if err != nil {
+			return err
+		}
+
+		data, err = json.MarshalIndent(readings, "", "  ")
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
 	if err != nil {
 		log.Panic().Err(err).Msg("Failed to load temperature readings from DB.")
 	}
-	tx.Commit()
-
-	data, err := json.MarshalIndent(readings, "", "  ")
-	if err != nil {
-		log.Panic().Err(err).Msg("Failed to serialize temperature readings to JSON.")
-	}
 
 	fmt.Fprintf(w, string(data))
 }
 
 func (a *API) GetStateChanges(w http.ResponseWriter, r *http.Request) {
 	defer sentry.Recover()
-
-	ctx := context.Background()
-	tx, err := a.db.Begin()
-	if err != nil {
-		log.Panic().Err(err).Msg("Failed to start DB transaction.")
-	}
+	ctxb := context.Background()
 
 	keys, ok := r.URL.Query()["since"]
 	if !ok || len(keys[0]) < 1 {
@@ -114,15 +110,23 @@ func (a *API) GetStateChanges(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	dbCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
+	ctx, cancel := context.WithTimeout(ctxb, 30*time.Second)
 	defer cancel()
-	readings, err := dal.LoadChamberStateChangesSince(dbCtx, tx, since)
+	var data []byte
+	err = a.db.InReadOnlyTransaction(ctx, func(tx *sql.Tx) error {
+		readings, err := dal.LoadChamberStateChangesSince(ctx, tx, since)
 		if err != nil {
-		log.Panic().Err(err).Msg("Failed to load temperature readings from DB.")
+			return err
 		}
-	tx.Commit()
 
-	data, err := json.MarshalIndent(readings, "", "  ")
+		data, err = json.MarshalIndent(readings, "", "  ")
+		if err != nil {
+			return err
+		}
+
+		return nil
+	})
+
 	if err != nil {
 		log.Panic().Err(err).Msg("Failed to serialize temperature readings to JSON.")
 	}

internal/controllers/chamber.go

@@ -1,9 +1,11 @@
 package controllers
 
 import (
+	"context"
 	"sync"
 	"time"
 
+	"git.joco.dk/sng/fermentord/pkg/temperature"
 	"github.com/rs/zerolog/log"
 )
 
@@ -16,13 +18,14 @@ const (
 )
 
 type ChamberController struct {
-	config *Config
+	ConfigUpdates chan ControllerConfig
+	config        ControllerConfig
 
 	// Current state.
 	chamberState           ChamberState
 	lastChamberStateChange time.Time
+	lastCoolerStateChange  time.Time
 	C                      chan ChamberState
-	mutex                  *sync.Mutex
 
 	name string
 
@@ -31,48 +34,139 @@ type ChamberController struct {
 	chamberTemperature float64
 	wortTemperature    float64
 
+	chTemp <-chan temperature.TemperatureReading
+
 	pid *PIDController
-	initialized bool
 }
 
-func NewChamberController(name string, config *Config) *ChamberController {
+func NewChamberController(name string, config ControllerConfig, chTemp <-chan temperature.TemperatureReading) *ChamberController {
 	return &ChamberController{
 		C:             make(chan ChamberState),
 		name:          name,
 		config:        config,
 		pid:           NewPIDController(config.PID.Kp, config.PID.Ki, config.PID.Kd),
-		mutex:  &sync.Mutex{},
+		chTemp:        chTemp,
+		chamberState:  ChamberStateIdle,
+		ConfigUpdates: make(chan ControllerConfig, 1),
 	}
 }
 
-func (p *ChamberController) Run() {
+func (p *ChamberController) Run(ctx context.Context, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	ticker := time.NewTicker(1 * time.Second)
+
 	for {
+		select {
+		case <-ticker.C:
+			state := p.computeChamberState()
+			p.setChamberState(state)
+
+		case temp := <-p.chTemp:
+			p.setTemperature(temp)
+
+		case c := <-p.ConfigUpdates:
+			p.config = c
+
+		case <-ctx.Done():
+			ticker.Stop()
+			p.setChamberState(ChamberStateIdle)
+			return
+		}
+	}
+}
+
+func (p *ChamberController) setTemperature(t temperature.TemperatureReading) {
+	switch t.Sensor {
+	case p.config.Sensor.Ambient:
+		p.ambientTemperature = t.Degrees()
+
+	case p.config.Sensor.Chamber:
+		p.chamberTemperature = t.Degrees()
+
+	case p.config.Sensor.Wort:
+		p.wortTemperature = t.Degrees()
+
+	default:
+		log.Warn().
+			Str("sensor", t.Sensor).
+			Int64("temp", t.MilliDegrees).
+			Msg("Unknown sensor")
+	}
+}
+
+func (p *ChamberController) setChamberState(state ChamberState) {
+	if state == p.chamberState {
+		return
+	}
+
+	log.Info().
+		Int("from", int(p.chamberState)).
+		Int("to", int(state)).
+		Msgf("State changed")
+
+	if p.chamberState == ChamberStateCooling || state == ChamberStateCooling {
+		p.lastCoolerStateChange = time.Now()
+	}
+
+	p.chamberState = state
+	p.lastChamberStateChange = time.Now()
+	p.C <- state
+}
+
+func (p *ChamberController) computeChamberState() ChamberState {
 	offset := p.pid.Compute(p.wortTemperature, p.config.FermentationTemperature)
 	chamberTargetTemp := p.config.FermentationTemperature + offset
-		log.Debug().Float64("chamber_target_temp", chamberTargetTemp).Send()
+	log.Debug().
+		Float64("amb_temp", p.ambientTemperature).
+		Float64("chamber_temp", p.chamberTemperature).
+		Float64("wort_temp", p.wortTemperature).
+		Float64("setpoint_temp", p.config.FermentationTemperature).
+		Float64("offset", offset).
+		Float64("chamber_target_temp", chamberTargetTemp).
+		Float64("kp", p.pid.kp).
+		Float64("ki", p.pid.ki).
+		Float64("kd", p.pid.kd).
+		Send()
 
-		// TODO Merge hysteresis algorithm into this one.
+	runtimeSecs := time.Since(p.lastChamberStateChange).Seconds()
 
-		if !p.initialized {
-			// heater off
-			// cooler off
-			continue
+	if p.chamberState == ChamberStateCooling {
+		// Ensure compressor min. runtime
+		if runtimeSecs < p.config.Limits.MinCoolerRuntimeSecs {
+			return p.chamberState
 		}
 
-		if p.wortTemperature < p.config.FermentationTemperature && p.chamberTemperature < chamberTargetTemp {
-			// heater on
-		} else if p.wortTemperature >= p.config.FermentationTemperature || p.chamberTemperature >= chamberTargetTemp {
-			// heater off
-		} else {
-			// heater off
+		// Limit compressor runtime
+		if runtimeSecs > p.config.Limits.MaxCoolerRuntimeSecs {
+			return ChamberStateIdle
 		}
 
-		if p.wortTemperature > p.config.FermentationTemperature && p.chamberTemperature > chamberTargetTemp {
-			// cooler on
-		} else if p.wortTemperature <= p.config.FermentationTemperature || p.chamberTemperature <= chamberTargetTemp {
-			// cooler off
-		} else {
-			// cooler off
+		// Limit chamber min. temp.
+		if p.chamberTemperature < p.config.Limits.MinChamberTemperature {
+			return ChamberStateIdle
 		}
 	}
+
+	var next ChamberState
+	heater := p.wortTemperature < p.config.FermentationTemperature-p.config.DeltaTemperature && p.chamberTemperature < chamberTargetTemp-p.config.DeltaTemperature
+	cooler := p.wortTemperature > p.config.FermentationTemperature+p.config.DeltaTemperature && p.chamberTemperature > chamberTargetTemp+p.config.DeltaTemperature
+
+	if cooler && heater {
+		// This should not happen!
+		next = ChamberStateIdle
+	} else if !cooler && !heater {
+		next = ChamberStateIdle
+	} else if cooler {
+		next = ChamberStateCooling
+	} else if heater {
+		next = ChamberStateHeating
+	}
+
+	// Ensure compressor cooldown
+	if p.chamberState != ChamberStateCooling && next == ChamberStateCooling && time.Since(p.lastCoolerStateChange).Seconds() < p.config.Limits.MinCoolerCooldownSecs {
+		return ChamberStateIdle
+	}
+
+	return next
 }

internal/controllers/config.go

@@ -1,12 +1,22 @@
 package controllers
 
-type Config struct {
+type ControllerConfig struct {
+	Sensor struct {
+		Wort    string `mapstructure:"wort"`
+		Chamber string `mapstructure:"chamber"`
+		Ambient string `mapstructure:"ambient"`
+	} `mapstructure:"sensors"`
+
 	FermentationTemperature float64 `mapstructure:"fermentation_temp"`
-	MaxWortDelta            float64 `mapstructure:"max_wort_delta"`
+	DeltaTemperature        float64 `mapstructure:"delta_temp"`
+
+	Limits struct {
 		MinChamberTemperature float64 `mapstructure:"min_chamber_temp"`
 		MinCoolerRuntimeSecs  float64 `mapstructure:"min_cooler_runtime_secs"`  // 900
 		MaxCoolerRuntimeSecs  float64 `mapstructure:"max_cooler_runtime_secs"`  // 86400
 		MinCoolerCooldownSecs float64 `mapstructure:"min_cooler_cooldown_secs"` // 900
+	} `mapstructure:"limits"`
+
 	PID struct {
 		Kp float64 `mapstructure:"kp"` // 2.0
 		Ki float64 `mapstructure:"ki"` // 0.0001

internal/controllers/hysteresis.go

@@ -1,226 +0,0 @@
-package controllers
-
-import (
-	"sync"
-	"time"
-
-	"github.com/rs/zerolog/log"
-)
-
-// Hysteresis will only run when the ambient temperature is above the
-// fermentation temperature. The compressor will run until the wort
-// is cooled to FermentationTemperature, the chamber is cooled to
-// MinChamberTemperature or the compressor has run for MaxCoolerRuntimeSecs.
-// The compressor will run for min. MinCoolerRuntimeSecs before switching off,
-// regardless of temperatures. Once turned off, the compressor will not be
-// turned on before MinCoolerCooldownSecs has expired, regardless of temperatures.
-type Hysteresis struct {
-	config *Config
-
-	// Current state.
-	coolerState           bool
-	lastCoolerStateChange time.Time
-	C                     chan bool
-	mutex                 *sync.Mutex
-
-	name string
-
-	// Current temperature readings.
-	ambientTemperature float64
-	chamberTemperature float64
-	wortTemperature    float64
-}
-
-func NewHysteresis(name string) *Hysteresis {
-	return &Hysteresis{
-		C:     make(chan bool),
-		name:  name,
-		mutex: &sync.Mutex{},
-	}
-}
-
-func (h *Hysteresis) SetConfig(newConfig *Config) {
-	h.lock()
-	h.config = newConfig
-	h.unlock()
-	h.update()
-}
-
-func (h *Hysteresis) UpdateAmbientTemperature(value float64) {
-	h.lock()
-	h.ambientTemperature = value
-	h.unlock()
-	h.update()
-}
-
-func (h *Hysteresis) UpdateChamberTemperature(value float64) {
-	h.lock()
-	h.chamberTemperature = value
-	h.unlock()
-	h.update()
-}
-
-func (h *Hysteresis) UpdateWortTemperature(value float64) {
-	h.lock()
-	h.wortTemperature = value
-	h.unlock()
-	h.update()
-}
-
-func (h *Hysteresis) lock() {
-	h.mutex.Lock()
-}
-
-func (h *Hysteresis) unlock() {
-	h.mutex.Unlock()
-}
-
-func (h *Hysteresis) GetCoolerState() bool {
-	return h.coolerState
-}
-
-func (h *Hysteresis) setState(state bool) {
-	h.lock()
-
-	if state == h.coolerState {
-		h.unlock()
-		return
-	}
-
-	log.Debug().Bool("state", state).Msg("Setting state")
-	h.coolerState = state
-	h.lastCoolerStateChange = time.Now()
-	h.unlock()
-
-	h.C <- state
-}
-
-func (h *Hysteresis) update() {
-	// Compressor runtime has highest priority.
-	lastStateChangeAgeSecs := time.Since(h.lastCoolerStateChange).Seconds()
-	if h.coolerState {
-		// Keep the cooler running until min. runtime is reached.
-		if lastStateChangeAgeSecs < h.config.MinCoolerRuntimeSecs {
-			log.Debug().
-				Str("name", h.name).
-				Float64("runtime", lastStateChangeAgeSecs).
-				Float64("min_runtime", h.config.MinCoolerRuntimeSecs).
-				Bool("state", h.coolerState).
-				Msg("Cooler kept running as it's runtime threshold is not yet reached.")
-			return
-		}
-
-		// Stop the cooler if it's runtime exceeds max.
-		if lastStateChangeAgeSecs > h.config.MaxCoolerRuntimeSecs {
-			log.Info().
-				Str("name", h.name).
-				Float64("runtime", lastStateChangeAgeSecs).
-				Float64("max_runtime", h.config.MaxCoolerRuntimeSecs).
-				Bool("state", false).
-				Msg("Cooler stopped as it's runtime exceeds max. threshold.")
-			h.setState(false)
-			return
-		}
-	} else {
-		// Keep the cooler off until min. cooldown time is reached.
-		if lastStateChangeAgeSecs < h.config.MinCoolerCooldownSecs {
-			log.Debug().
-				Str("name", h.name).
-				Float64("runtime", lastStateChangeAgeSecs).
-				Float64("min_cooldown", h.config.MinCoolerCooldownSecs).
-				Bool("state", h.coolerState).
-				Msg("Cooler kept off as it's cooldown time threshold is not yet reached.")
-			return
-		}
-	}
-
-	// Do not allow the cooler to run when the ambient temperature is below
-	// the fermentation temperature.
-	if h.ambientTemperature < h.config.FermentationTemperature {
-		if h.coolerState {
-			log.Info().
-				Str("name", h.name).
-				Float64("ambient_temp", h.ambientTemperature).
-				Float64("fermentation_temp", h.config.FermentationTemperature).
-				Msg("Turn off cooler as ambient temperature is less than fermentation temperature.")
-			h.setState(false)
-		} else {
-			log.Debug().
-				Str("name", h.name).
-				Float64("ambient_temp", h.ambientTemperature).
-				Float64("fermentation_temp", h.config.FermentationTemperature).
-				Msg("Cooler kept off as ambient temperature is less than fermentation temperature.")
-		}
-		return
-	}
-
-	// Do not allow the cooler to run if the chamber temperature is below
-	// minimum.
-	if h.chamberTemperature <= h.config.MinChamberTemperature {
-		if h.coolerState {
-			log.Info().
-				Str("name", h.name).
-				Float64("chamber_temp", h.chamberTemperature).
-				Float64("min_chamber_temp", h.config.MinChamberTemperature).
-				Msg("Cooler turned off as chamber temperature dropped below threshold.")
-			h.setState(false)
-		} else {
-			log.Debug().
-				Str("name", h.name).
-				Float64("ambient_temp", h.ambientTemperature).
-				Float64("fermentation_temp", h.config.FermentationTemperature).
-				Msg("Cooler kept off as chamber temperature is below threshold.")
-		}
-		return
-	}
-
-	// Keep the cooler stopped until the wort delta temperature reaches it's threshold.
-	delta := h.wortTemperature - h.config.FermentationTemperature
-	if h.coolerState {
-		// Keep the cooler running until the wort reaches the desired temp.
-		if delta <= 0 {
-			// TODO Investigate how much the wort temp. drops below fermentation temp.
-			// TODO A threshold may be needed.
-			log.Info().
-				Str("name", h.name).
-				Float64("wort_temp", h.wortTemperature).
-				Float64("fermentation_temp", h.config.FermentationTemperature).
-				Float64("delta", delta).
-				Float64("max_wort_delta", h.config.MaxWortDelta).
-				Msg("Cooler stopped as wort is cooled down to fermentation temp.")
-			h.setState(false)
-			return
-		} else {
-			log.Debug().
-				Str("name", h.name).
-				Float64("wort_temp", h.wortTemperature).
-				Float64("fermentation_temp", h.config.FermentationTemperature).
-				Float64("delta", delta).
-				Float64("max_wort_delta", h.config.MaxWortDelta).
-				Msg("Cooler kept running as the wort has not yet reached fermentation temp.")
-		}
-	} else {
-		// Start the cooler when delta exceeds threshold.
-		if delta > h.config.MaxWortDelta {
-			log.Info().
-				Str("name", h.name).
-				Float64("wort_temp", h.wortTemperature).
-				Float64("fermentation_temp", h.config.FermentationTemperature).
-				Float64("delta", delta).
-				Float64("max_wort_delta", h.config.MaxWortDelta).
-				Msg("Cooler started as wort delta exceeds threshold.")
-			h.setState(true)
-			return
-		} else {
-			log.Debug().
-				Str("name", h.name).
-				Float64("wort_temp", h.wortTemperature).
-				Float64("fermentation_temp", h.config.FermentationTemperature).
-				Float64("delta", delta).
-				Float64("max_wort_delta", h.config.MaxWortDelta).
-				Msg("Cooler kept off as delta does not yet exceed threshold.")
-			// TODO If this is reached, then we can lower the delta as min. cooldown is reached.
-			// TODO This is relevant for PID.
-		}
-	}
-}

internal/controllers/hysteresis_test.go

@@ -1,52 +0,0 @@
-package controllers
-
-import (
-	"testing"
-	"time"
-)
-
-func discard(h *Hysteresis) {
-	for {
-		<-h.C
-	}
-}
-
-func TestHysteresisNormalCooling(t *testing.T) {
-	c := &Config{
-		FermentationTemperature: 20,
-		MaxWortDelta:            0.5,
-		MinChamberTemperature:   2,
-		MinCoolerRuntimeSecs:    300,
-		MaxCoolerRuntimeSecs:    86400,
-		MinCoolerCooldownSecs:   300,
-	}
-
-	h := NewHysteresis("test")
-	h.config = c
-	h.ambientTemperature = 25
-	h.chamberTemperature = 22
-	h.wortTemperature = 20
-	go discard(h)
-	h.update()
-
-	assert := func(expectedState bool) {
-		actualState := h.GetCoolerState()
-		if actualState != expectedState {
-			t.Errorf("Expected cooler state %v, but got %v", expectedState, actualState)
-		}
-	}
-
-	assert(false)
-
-	h.lastCoolerStateChange = h.lastCoolerStateChange.Add(-1 * time.Hour)
-	h.UpdateWortTemperature(20.5)
-	assert(false)
-
-	h.lastCoolerStateChange = h.lastCoolerStateChange.Add(-1 * time.Hour)
-	h.UpdateWortTemperature(20.6)
-	assert(true)
-
-	h.lastCoolerStateChange = h.lastCoolerStateChange.Add(-1 * time.Hour)
-	h.UpdateWortTemperature(20)
-	assert(false)
-}

internal/dal/db.go

@@ -1,6 +1,7 @@
 package dal
 
 import (
+	"context"
 	"database/sql"
 
 	_ "modernc.org/sqlite"
@@ -22,15 +23,46 @@ func NewDAL(dsn string) (*DAL, error) {
 	return dal, nil
 }
 
-func (dal *DAL) Close() error {
-	return dal.db.Close()
+func (p *DAL) Close() error {
+	return p.db.Close()
 }
 
-func (dal *DAL) Initialize() error {
-	// TODO
+func (p *DAL) InReadWriteTransaction(ctx context.Context, fn func(tx *sql.Tx) error) error {
+	tx, err := p.db.BeginTx(ctx, &sql.TxOptions{})
+	if err != nil {
+		return err
+	}
+
+	if err = fn(tx); err != nil {
+		if err2 := tx.Rollback(); err2 != nil {
+			return err2
+		}
+		return err
+	}
+
+	if err = tx.Commit(); err != nil {
+		return err
+	}
+
 	return nil
 }
 
-func (dal *DAL) Begin() (*sql.Tx, error) {
-	return dal.db.Begin()
+func (p *DAL) InReadOnlyTransaction(ctx context.Context, fn func(tx *sql.Tx) error) error {
+	tx, err := p.db.BeginTx(ctx, &sql.TxOptions{ReadOnly: true})
+	if err != nil {
+		return err
+	}
+
+	if err = fn(tx); err != nil {
+		if err2 := tx.Rollback(); err2 != nil {
+			return err2
+		}
+		return err
+	}
+
+	if err = tx.Commit(); err != nil {
+		return err
+	}
+
+	return nil
 }

internal/dal/db_migrations.go

@@ -1,5 +1,7 @@
 package dal
 
+// SQL migrations https://github.com/golang-migrate/migrate/tree/master/database/sqlite
+
 import (
 	"embed"
 	"net/http"

internal/dal/readings.go

@@ -56,9 +56,9 @@ func LoadTemperatureReadingsSince(ctx context.Context, tx *sql.Tx, since time.Ti
 	return readings, nil
 }
 
-func SaveTemperatureReading(ctx context.Context, tx *sql.Tx, sensor string, value int64) error {
-	q := "INSERT INTO temperature_reading (sensor, value) VALUES (?, ?)"
-	_, err := tx.ExecContext(ctx, q, sensor, value)
+func SaveTemperatureReading(ctx context.Context, tx *sql.Tx, ts time.Time, sensor string, value int64) error {
+	q := "INSERT INTO temperature_reading (c_time, sensor, value) VALUES (?, ?, ?)"
+	_, err := tx.ExecContext(ctx, q, ts, sensor, value)
 	return err
 }
 

internal/hw/gpio.go

@@ -6,7 +6,6 @@ import (
 
 const (
 	pinCoolerPower = 20
-	pinFanPower    = 16
 	pinHeaterPower = 21
 
 	off = 0
@@ -16,7 +15,6 @@ const (
 type Gpio struct {
 	chip        *gpiod.Chip
 	coolerPower *gpiod.Line
-	fanPower    *gpiod.Line
 	heaterPower *gpiod.Line
 }
 
@@ -34,11 +32,6 @@ func NewGpio() (*Gpio, error) {
 		return nil, err
 	}
 
-	p.fanPower, err = p.chip.RequestLine(pinFanPower, gpiod.AsOutput(1))
-	if err != nil {
-		return nil, err
-	}
-
 	p.heaterPower, err = p.chip.RequestLine(pinHeaterPower, gpiod.AsOutput(1))
 	if err != nil {
 		return nil, err
@@ -49,11 +42,9 @@ func NewGpio() (*Gpio, error) {
 
 func (p *Gpio) Close() {
 	p.coolerPower.SetValue(off)
-	p.fanPower.SetValue(off)
 	p.heaterPower.SetValue(off)
 
 	p.heaterPower.Close()
-	p.fanPower.Close()
 	p.coolerPower.Close()
 	p.chip.Close()
 }

internal/metrics/prometheus.go

@@ -5,11 +5,17 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promauto"
 )
 
+const (
+	MetricStateIdle float64 = iota
+	MetricStateCooling
+	MetricStateHeating
+)
+
 var (
 	State = promauto.NewGauge(prometheus.GaugeOpts{
 		Namespace: "fermentord",
 		Subsystem: "state",
-		Name:      "state_current",
+		Name:      "current",
 		Help:      "The state of the fermentor. 0=idle, 1=cooling, 2=heating",
 	})
 

pkg/daemon/wait.go

@@ -0,0 +1,28 @@
+package daemon
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/rs/zerolog/log"
+)
+
+var (
+	Interrupt           = os.Interrupt
+	Quit      os.Signal = syscall.SIGQUIT
+	Terminate os.Signal = syscall.SIGTERM
+)
+
+func WaitForSignal(sig ...os.Signal) {
+	ch := make(chan os.Signal, 1)
+	signal.Notify(ch, sig...)
+	s := <-ch
+	log.Debug().
+		Str("signal", s.String()).
+		Msg("Signal caught")
+}
+
+func WaitForExitSignal() {
+	WaitForSignal(Interrupt, Quit, Terminate)
+}

pkg/temperature/ds18b20.go

@@ -1,70 +1,86 @@
 package temperature
 
+// Kernel documentation: https://www.kernel.org/doc/html/latest/w1/slaves/w1_therm.html
+
 import (
 	"context"
 	"errors"
 	"io/ioutil"
+	"os"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 
 	"git.joco.dk/sng/fermentord/internal/metrics"
+	"github.com/getsentry/sentry-go"
 	"github.com/rs/zerolog/log"
 )
 
 var (
-	ErrReadSensor = errors.New("Failed to read sensor temperature")
-
-	C chan *TemperatureReading
-
-	sensors []string
-	mutex   *sync.Mutex
-	ticker  *time.Ticker
+	// ErrReadSensor indicates that the sensor could not be read
+	ErrReadSensor = errors.New("failed to read sensor")
 )
 
-func Initialize(readingInterval time.Duration) {
-	C = make(chan *TemperatureReading)
+var (
+	// C receives the temperature readings
+	C chan TemperatureReading
+
+	// ConfigUpdates receives the list of sensors to read
+	ConfigUpdates chan []string
+	sensors       []string
+)
+
+func Initialize() {
 	sensors = make([]string, 0)
-	mutex = &sync.Mutex{}
-	ticker = time.NewTicker(readingInterval)
+	C = make(chan TemperatureReading, 30)
+	ConfigUpdates = make(chan []string, 1)
 }
 
-func SetSensors(newSensors []string) {
-	mutex.Lock()
-	sensors = newSensors
-	mutex.Unlock()
-}
-
-func Serve(ctx context.Context, wg *sync.WaitGroup) {
+func PollSensors(ctx context.Context, wg *sync.WaitGroup, readingInterval time.Duration) {
 	defer wg.Done()
 
+	if readingInterval < 750*time.Millisecond {
+		log.Fatal().
+			Dur("interval", readingInterval).
+			Msg("Reading interval must be at least 750 ms.")
+	}
+
+	ticker := time.NewTicker(readingInterval)
+	defer ticker.Stop()
+
 	for {
 		select {
 		case <-ticker.C:
+			// Trigger a bulk read and wait 750ms for sensors to convert data.
+			triggerBulkRead()
+			time.Sleep(750 * time.Millisecond)
+
 			readSensors()
 
+		case c := <-ConfigUpdates:
+			sensors = c
+
 		case <-ctx.Done():
-			ticker.Stop()
+			close(C)
 			return
 		}
 	}
 }
 
 func readSensors() {
-	mutex.Lock()
-	defer mutex.Unlock()
-
 	for _, sensor := range sensors {
 		start := time.Now()
 		t, err := read(sensor)
 		dur := time.Since(start).Seconds()
 
 		if err != nil {
+			sentry.CaptureException(err)
 			log.Error().
 				Err(err).
 				Str("sensor", sensor).
 				Msg("Error reading temperature sensor.")
+			continue
 		}
 
 		metrics.TemperatureSensorReadingDegreesCelcius.
@@ -75,7 +91,7 @@ func readSensors() {
 			WithLabelValues("sensor", sensor).
 			Observe(dur)
 
-		C <- &TemperatureReading{
+		C <- TemperatureReading{
 			Time:         time.Now(),
 			Sensor:       sensor,
 			MilliDegrees: t,
@@ -83,6 +99,17 @@ func readSensors() {
 	}
 }
 
+func triggerBulkRead() error {
+	f, err := os.OpenFile("/sys/bus/w1/w1_bus_master/therm_bulk_read", os.O_APPEND, os.ModeAppend)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	_, err = f.WriteString("trigger\n")
+	return err
+}
+
 // read returns the temperature of the specified sensor in millidegrees celcius.
 func read(sensor string) (int64, error) {
 	path := "/sys/bus/w1/devices/" + sensor + "/w1_slave"