improve logging & add cache to tcl & velov

epd/epd.go

@@ -3,7 +3,8 @@ package epd
 import (
 	"fmt"
 	"image"
-	"log"
+	"log/slog"
+	"os"
 	"periph.io/x/conn/v3/gpio"
 	"periph.io/x/conn/v3/physic"
 	"periph.io/x/conn/v3/spi"
@@ -61,7 +62,8 @@ func (e *EPD) sendCommand(cmd byte) {
 	e.dcPin.Out(gpio.Low)
 	e.csPin.Out(gpio.Low)
 	if _, err := e.spiWrite([]byte{cmd}); err != nil {
-		log.Fatalf("writing to spi: %v", err)
+		slog.Error("writing to spi", "err", err)
+		os.Exit(1)
 	}
 	e.csPin.Out(gpio.High)
 }
@@ -70,7 +72,8 @@ func (e *EPD) sendData(data byte) {
 	e.dcPin.Out(gpio.High)
 	e.csPin.Out(gpio.Low)
 	if _, err := e.spiWrite([]byte{data}); err != nil {
-		log.Fatalf("writing to spi: %v", err)
+		slog.Error("writing to spi", "err", err)
+		os.Exit(1)
 	}
 	e.csPin.Out(gpio.High)
 }
@@ -82,7 +85,8 @@ func (e *EPD) sendDataSlice(data []byte) {
 	if toSend <= maxSize {
 		e.csPin.Out(gpio.Low)
 		if _, err := e.spiWrite(data); err != nil {
-			log.Fatalf("writing to spi: %v", err)
+			slog.Error("writing to spi", "err", err)
+			os.Exit(1)
 		}
 		e.csPin.Out(gpio.High)
 		return
@@ -93,7 +97,8 @@ func (e *EPD) sendDataSlice(data []byte) {
 		chunk := data[cursor:min(cursor+maxSize, toSend)]
 		e.csPin.Out(gpio.Low)
 		if _, err := e.spiWrite(chunk); err != nil {
-			log.Fatalf("writing to spi: %v", err)
+			slog.Error("writing to spi", "err", err)
+			os.Exit(1)
 		}
 		e.csPin.Out(gpio.High)
 		cursor = min(cursor+maxSize, toSend)
@@ -120,7 +125,7 @@ func (e *EPD) readBusy() {
 }
 
 func (e *EPD) turnOn() error {
-	log.Println("turning on")
+	slog.Info("turning on")
 	if err := e.resetPin.Out(gpio.Low); err != nil {
 		return fmt.Errorf("setting reset pin to low: %w", err)
 	}
@@ -151,7 +156,7 @@ func (e *EPD) turnOn() error {
 }
 
 func (e *EPD) Init() error {
-	log.Println("initializing EPD")
+	slog.Info("initializing EPD")
 
 	if err := e.turnOn(); err != nil {
 		return fmt.Errorf("turning on: %w", err)
@@ -188,7 +193,7 @@ func (e *EPD) Init() error {
 }
 
 func (e *EPD) InitFast() error {
-	log.Println("initializing Fast EPD")
+	slog.Info("initializing Fast EPD")
 
 	if err := e.turnOn(); err != nil {
 		return fmt.Errorf("turning on: %w", err)
@@ -219,19 +224,19 @@ func (e *EPD) InitFast() error {
 }
 
 func (e *EPD) Clear() {
-	log.Println("clearing epd")
+	slog.Info("clearing epd")
 	e.Send(image.White)
 }
 
 func (e *EPD) Refresh() {
-	log.Println("refreshing...")
+	slog.Info("refreshing...")
 	e.sendCommand(0x12)
 	time.Sleep(100 * time.Millisecond)
 	e.readBusy()
 }
 
 func (e *EPD) Sleep() error {
-	log.Println("sleeping display...")
+	slog.Info("sleeping display...")
 	e.sendCommand(0x02)
 	e.readBusy()
 
@@ -247,7 +252,7 @@ func (e *EPD) Sleep() error {
 }
 
 func (e *EPD) turnOff() error {
-	log.Println("turning off...")
+	slog.Info("turning off...")
 	if err := e.spiReg.Close(); err != nil {
 		return fmt.Errorf("closing SPI: %w", err)
 	}
@@ -261,11 +266,11 @@ func (e *EPD) turnOff() error {
 
 func (e *EPD) Send(img image.Image) {
 	if img == nil {
-		log.Println("empty img")
+		slog.Info("empty img")
 		return
 	}
 
-	log.Println("sending img...")
+	slog.Info("sending img...")
 	toSend := make([]byte, 0, e.height*e.width/8)
 	toSend2 := make([]byte, 0, e.height*e.width/8)
 	for row := 0; row < e.height; row++ {

fete/fete.go

@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"github.com/carlmjohnson/requests"
-	"log"
+	"log/slog"
 	"net/http"
 	"os"
 	"time"
@@ -70,15 +70,15 @@ func (f Fete) dumpToDisk(location string) error {
 
 func (c *Client) GetFete(ctx context.Context, date time.Time) (res *Fete, err error) {
 	if val, err := loadFromDisk(c.config.CacheLocation); nil == err {
-		log.Println("found fete in cache")
+		slog.InfoContext(ctx, "found fete in cache")
 		if val.Day == date.Day() && val.Month == int(date.Month()) {
-			log.Println("fete cache is up to date")
+			slog.InfoContext(ctx, "fete cache is up to date")
 			return &val, nil
 		}
-		log.Println("fete cache is old, fetching...")
+		slog.InfoContext(ctx, "fete cache is old, fetching...")
 	}
 
-	log.Println("querying fete")
+	slog.InfoContext(ctx, "querying fete")
 	err = requests.URL("https://fetedujour.fr").
 		Pathf("/api/v2/%v/json-normal-%d-%d", c.config.APIKey, date.Day(), date.Month()).
 		UserAgent("e-paper-display").
@@ -90,7 +90,7 @@ func (c *Client) GetFete(ctx context.Context, date time.Time) (res *Fete, err er
 	}
 
 	if err := res.dumpToDisk(c.config.CacheLocation); err != nil {
-		log.Printf("error dumping files to disk: %v\n", err)
+		slog.ErrorContext(ctx, "error dumping files to disk", "err", err)
 	}
 
 	return res, nil

img.go

@@ -14,7 +14,7 @@ import (
 	"github.com/llgcode/draw2d/draw2dimg"
 	"image"
 	"image/color"
-	"log"
+	"log/slog"
 	"math"
 	"strconv"
 	"strings"
@@ -53,7 +53,7 @@ func getImg(ctx context.Context, nowFunc func() time.Time, transportsClient *tra
 
 		bus, err = transportsClient.GetTCLPassages(ctx, 290)
 		if err != nil {
-			log.Println("error getting bus:", err)
+			slog.ErrorContext(ctx, "error getting bus", "err", err)
 		}
 	}()
 	go func() {
@@ -66,7 +66,7 @@ func getImg(ctx context.Context, nowFunc func() time.Time, transportsClient *tra
 
 		tram, err = transportsClient.GetTCLPassages(ctx, 34068)
 		if err != nil {
-			log.Println("error getting tram:", err)
+			slog.ErrorContext(ctx, "error getting tram", "err", err)
 		}
 	}()
 	go func() {
@@ -79,7 +79,7 @@ func getImg(ctx context.Context, nowFunc func() time.Time, transportsClient *tra
 
 		velovRoc, err = transportsClient.GetVelovStation(ctx, 10044)
 		if err != nil {
-			log.Println("error getting velov:", err)
+			slog.ErrorContext(ctx, "error getting velov", "err", err)
 		}
 	}()
 	go func() {
@@ -92,7 +92,7 @@ func getImg(ctx context.Context, nowFunc func() time.Time, transportsClient *tra
 
 		fetes, err = feteClient.GetFete(ctx, nowFunc())
 		if err != nil {
-			log.Println("error getting fetes:", err)
+			slog.ErrorContext(ctx, "error getting fetes", "err", err)
 		}
 	}()
 	go func() {
@@ -105,7 +105,7 @@ func getImg(ctx context.Context, nowFunc func() time.Time, transportsClient *tra
 
 		wthr, err = weatherClient.GetWeather(ctx)
 		if err != nil {
-			log.Println("error getting weather:", err)
+			slog.ErrorContext(ctx, "error getting weather", "err", err)
 		}
 	}()
 	go func() {
@@ -118,7 +118,7 @@ func getImg(ctx context.Context, nowFunc func() time.Time, transportsClient *tra
 
 		msg, err = hassClient.GetState(ctx, "input_text.e_paper_message")
 		if err != nil {
-			log.Println("error getting hass message:", err)
+			slog.ErrorContext(ctx, "error getting hass message", "err", err)
 		}
 	}()
 
@@ -141,7 +141,7 @@ func getImg(ctx context.Context, nowFunc func() time.Time, transportsClient *tra
 	drawVelov(gc, velovRoc, 365)
 	drawDate(gc, nowFunc())
 	drawFete(gc, fetes)
-	drawWeather(gc, wthr)
+	drawWeather(ctx, gc, wthr)
 	drawMsg(gc, msg)
 
 	return img, nil
@@ -152,13 +152,15 @@ func drawMsg(gc *draw2dimg.GraphicContext, quote string) {
 
 }
 
-func drawWeather(gc *draw2dimg.GraphicContext, wthr *weather.Prevision) {
+func drawWeather(ctx context.Context, gc *draw2dimg.GraphicContext, wthr *weather.Prevision) {
 	if wthr == nil {
 		return
 	}
 
-	if len(wthr.Daily) == 0 || len(wthr.Daily[0].Weather) == 0 {
+	dailyLen := len(wthr.Daily)
-		log.Println("missing daily or daily weather")
+	dailyWeatherLen := len(wthr.Daily[0].Weather)
+	if dailyLen == 0 || dailyWeatherLen == 0 {
+		slog.ErrorContext(ctx, "missing daily or daily weather", "daily_len", dailyLen, "daily_weather_len", dailyWeatherLen)
 		return
 	}
 
@@ -166,7 +168,7 @@ func drawWeather(gc *draw2dimg.GraphicContext, wthr *weather.Prevision) {
 	dailyWeather := daily.Weather[0]
 	err := drawWeatherIcon(gc, dailyWeather)
 	if err != nil {
-		log.Println("Failed to draw weather icon:", err)
+		slog.ErrorContext(ctx, "Failed to draw weather icon", "err", err)
 	}
 
 	text(gc, formatTemp(wthr.Current.Temp), 23, leftX, 120)

main.go

@@ -10,7 +10,7 @@ import (
 	"github.com/llgcode/draw2d"
 	_ "golang.org/x/image/bmp"
 	"golang.org/x/image/font/gofont/goregular"
-	"log"
+	"log/slog"
 	"os"
 	"time"
 )
@@ -18,14 +18,16 @@ import (
 const fontName = "default"
 
 func main() {
-	log.Println("starting...")
-
 	ctx := context.Background()
 
+	slog.InfoContext(ctx, "starting...")
+
 	font, err := truetype.Parse(goregular.TTF)
 	if err != nil {
-		log.Fatalf("loading font: %v\n", err)
+		slog.ErrorContext(ctx, "error loading font", "err", err)
+		os.Exit(1)
 	}
+
 	fontCache := MyFontCache{}
 	fontCache.Store(draw2d.FontData{Name: fontName}, font)
 	draw2d.SetFontCache(fontCache)
@@ -56,7 +58,9 @@ func main() {
 		initFastThreshold = minInitFastThreshold
 	}
 
-	log.Printf("sleep duration: %v\n", sleep)
+	slog.InfoContext(ctx, "config",
+		"sleep_duration", sleep,
+		"init_fast_threshold", initFastThreshold)
 
 	hassClient := home_assistant.New(nil, home_assistant.Config{
 		Token:   os.Getenv("HOME_ASSISTANT_TOKEN"),
@@ -72,8 +76,9 @@ func main() {
 		weatherClient,
 		hassClient,
 	); err != nil {
-		log.Fatal("error: ", err)
+		slog.ErrorContext(ctx, "error", "err", err)
+		os.Exit(1)
 	}
 
-	log.Println("done")
+	slog.InfoContext(ctx, "done")
 }

run_darwin_arm64.go

@@ -2,12 +2,12 @@ package main
 
 import (
 	"context"
+	"fmt"
 	"github.com/Crocmagnon/display-epaper/fete"
 	"github.com/Crocmagnon/display-epaper/home_assistant"
 	"github.com/Crocmagnon/display-epaper/transports"
 	"github.com/Crocmagnon/display-epaper/weather"
 	"github.com/llgcode/draw2d/draw2dimg"
-	"log"
 	"time"
 )
 
@@ -35,10 +35,11 @@ func run(
 		hassClient,
 	)
 	if err != nil {
-		log.Fatal(err)
+		return err
 	}
+
 	if err := draw2dimg.SaveToPngFile("out/black.png", img); err != nil {
-		log.Fatalf("error saving image: %v", err)
+		return fmt.Errorf("saving img: %w", err)
 	}
 
 	return nil

run_linux_arm64.go

@@ -10,6 +10,7 @@ import (
 	"github.com/Crocmagnon/display-epaper/weather"
 	"image"
 	"log"
+	"log/slog"
 	"os"
 	"periph.io/x/host/v3"
 	"time"
@@ -39,12 +40,12 @@ func run(
 	for {
 		select {
 		case <-ctx.Done():
-			log.Println("stopping because of context")
+			slog.InfoContext(ctx, "stopping because of context")
 			return ctx.Err()
 		default:
 		}
 
-		log.Println("running loop")
+		slog.InfoContext(ctx, "running loop")
 
 		img, err := loop(
 			ctx,
@@ -57,12 +58,12 @@ func run(
 			hassClient,
 		)
 		if err != nil {
-			log.Printf("error looping: %v\n", err)
+			slog.ErrorContext(ctx, "error looping", "err", err)
 		}
 
 		currentImg = img
 
-		log.Printf("time.Sleep(%v)\n", sleep)
+		slog.InfoContext(ctx, "sleep", "duration", sleep)
 		time.Sleep(sleep)
 	}
 }
@@ -95,17 +96,17 @@ func loop(
 	}
 
 	if imgEqual(currentImg, img, epd.Width, epd.Height) {
-		log.Println("Images are equal, doing nothing.")
+		slog.InfoContext(ctx, "Images are equal, doing nothing.")
 		return img, nil
 	}
 
 	defer func() {
 		if err := display.Sleep(); err != nil {
-			log.Printf("error sleeping: %v\n", err)
+			slog.ErrorContext(ctx, "error sleeping", "err", err)
 		}
 	}()
 
-	err := initDisplay(display, initFastThreshold)
+	err := initDisplay(ctx, display, initFastThreshold)
 	if err != nil {
 		return nil, fmt.Errorf("initializing display: %w", err)
 	}
@@ -125,32 +126,31 @@ func shouldDisplay(ctx context.Context, hassClient *home_assistant.Client) bool
 		return true
 	}
 
-	log.Printf("found dayNight=%v\n", dayNight)
-
 	hallLights, err := hassClient.GetState(ctx, "light.couloir")
 	if err != nil {
 		log.Printf("error getting hall lights: %v ; displaying anyway\n", err)
 		return true
 	}
 
-	log.Printf("found hallLights=%v\n", hallLights)
-
 	presentAway, err := hassClient.GetState(ctx, "input_select.house_present_away")
 	if err != nil {
 		log.Printf("error getting day night: %v ; displaying anyway\n", err)
 		return true
 	}
 
-	log.Printf("found presentAway=%v\n", presentAway)
+	slog.InfoContext(ctx, "home assistant states",
+		"hall_lights", hallLights,
+		"day_night", dayNight,
+		"present_away", presentAway)
 
 	res := (hallLights == "on" || dayNight == "day") && presentAway == "present"
-	log.Printf("shouldDisplay: %v\n", res)
+	slog.InfoContext(ctx, "computed should display", "should_display", res)
 	return res
 }
 
 const filename = "/perm/display-epaper-lastFullRefresh"
 
-func initDisplay(display *epd.EPD, threshold time.Duration) error {
+func initDisplay(ctx context.Context, display *epd.EPD, threshold time.Duration) error {
 	if canInitFast(threshold) {
 		err := display.InitFast()
 		if err != nil {
@@ -164,7 +164,7 @@ func initDisplay(display *epd.EPD, threshold time.Duration) error {
 		return fmt.Errorf("running full init: %w", err)
 	}
 
-	markInitFull()
+	markInitFull(ctx)
 
 	return nil
 }
@@ -178,10 +178,10 @@ func canInitFast(threshold time.Duration) bool {
 	return stat.ModTime().Add(threshold).After(time.Now())
 }
 
-func markInitFull() {
+func markInitFull(ctx context.Context) {
 	f, err := os.Create(filename)
 	if err != nil {
-		log.Printf("error marking full refresh: %v\n", err)
+		slog.ErrorContext(ctx, "error marking full refresh", "err", err)
 	}
 
 	f.Close()

transports/transports.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"fmt"
 	"github.com/carlmjohnson/requests"
+	"log/slog"
 	"net/http"
+	"time"
 )
 
 type Stop struct {
@@ -26,9 +28,17 @@ type Passages struct {
 type Config struct {
 }
 
+const cacheTimeout = 2 * time.Minute
+
 type Client struct {
 	client *http.Client
 	config Config
+
+	passagesCache     *Passages
+	passagesCacheTime time.Time
+
+	stationCache     *Station
+	stationCacheTime time.Time
 }
 
 func New(httpClient *http.Client, config Config) *Client {
@@ -48,11 +58,28 @@ func (c *Client) GetTCLPassages(ctx context.Context, stop int) (res *Passages, e
 		ToJSON(&res).
 		Fetch(ctx)
 	if err != nil {
+		if res = c.getPassagesCache(); res != nil {
+			slog.WarnContext(ctx, "retrieving passages from cache")
+			return res, nil
+		}
+
 		return nil, fmt.Errorf("calling api: %w", err)
 	}
+
+	c.passagesCache = res
+	c.passagesCacheTime = time.Now()
+
 	return res, nil
 }
 
+func (c *Client) getPassagesCache() *Passages {
+	if c.passagesCache != nil && time.Since(c.passagesCacheTime) < cacheTimeout {
+		return c.passagesCache
+	}
+
+	return nil
+}
+
 type Station struct {
 	Name             string `json:"name"`
 	BikesAvailable   int    `json:"bikes_available"`
@@ -67,7 +94,24 @@ func (c *Client) GetVelovStation(ctx context.Context, station int) (res *Station
 		ToJSON(&res).
 		Fetch(ctx)
 	if err != nil {
+		if res = c.getStationCache(); res != nil {
+			slog.WarnContext(ctx, "retrieving station from cache")
+			return res, nil
+		}
+
 		return nil, fmt.Errorf("calling api: %w", err)
 	}
+
+	c.stationCache = res
+	c.stationCacheTime = time.Now()
+
 	return res, nil
 }
+
+func (c *Client) getStationCache() *Station {
+	if c.stationCache != nil && time.Since(c.stationCacheTime) < cacheTimeout {
+		return c.stationCache
+	}
+
+	return nil
+}

weather/weather.go

@@ -6,7 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"github.com/carlmjohnson/requests"
-	"log"
+	"log/slog"
 	"net/http"
 	"os"
 	"time"
@@ -152,11 +152,11 @@ type Weather struct {
 
 func (c *Client) GetWeather(ctx context.Context) (res *Prevision, err error) {
 	if val, err := loadFromDisk(c.config.CacheLocation); nil == err {
-		log.Println("found weather in cache")
+		slog.InfoContext(ctx, "found weather in cache")
 		return &val, nil
 	}
 
-	log.Println("querying weather")
+	slog.InfoContext(ctx, "querying weather")
 
 	err = requests.URL("https://api.openweathermap.org/data/3.0/onecall").
 		Client(c.client).
@@ -173,7 +173,7 @@ func (c *Client) GetWeather(ctx context.Context) (res *Prevision, err error) {
 	}
 
 	if err := res.dumpToDisk(c.config.CacheLocation); err != nil {
-		log.Printf("error dumping files to disk: %v\n", err)
+		slog.ErrorContext(ctx, "error dumping files to disk", "err", err)
 	}
 
 	return res, nil