feat(services): Logging

main.go

@@ -137,9 +137,11 @@ func main() {
 
 	barcodeGenerator := &services.DefaultBarcodeService{
 		RedisClient: redisClient,
+		Logger:      logger.Named("DefaultBarcodeService"),
 	}
 	staticService := &services.DefaultStaticService{
-		Cache: make(map[string]string),
+		Cache:  make(map[string]string),
+		Logger: logger.Named("DefaultStaticService"),
 	}
 	handler := handlers.DefaultHandler{
 		Config:         config,
@@ -148,11 +150,13 @@ func main() {
 		Templater: &services.DefaultTemplater{
 			BarcodeService: barcodeGenerator,
 			StaticService:  staticService,
+			Logger:         logger.Named("DefaultTemplater"),
 		},
 		Converter: &services.GotenbergConverter{
 			BaseUrl: config.GotenbergBaseUrl,
+			Logger:  logger.Named("GotenbergConverter"),
 		},
-		Logger: logger,
+		Logger: logger.Named("DefaultHandler"),
 	}
 	logger.Debug("Initialized services")
 

services/barcode.go

@@ -8,7 +8,6 @@ import (
 	"image/color"
 	"image/draw"
 	"image/png"
-	"log"
 	"slices"
 	"time"
 
@@ -17,6 +16,7 @@ import (
 	"github.com/boombuler/barcode/ean"
 	"github.com/boombuler/barcode/qr"
 	"github.com/redis/go-redis/v9"
+	"go.uber.org/zap"
 )
 
 type BarcodeService interface {
@@ -26,19 +26,26 @@ type BarcodeService interface {
 
 type DefaultBarcodeService struct {
 	RedisClient *redis.Client
+	Logger      *zap.SugaredLogger
 }
 
 func (b *DefaultBarcodeService) GenerateBarcode(format string, content string, width int, height int, padding int) (bytes.Buffer, error) {
 	ctx := context.Background()
+	logger := b.Logger.Named("GenerateBarcode")
 
 	if !b.IsTypeSupported(format) {
+		logger.Errorw("Unsupported barcode type", "type", format)
 		return bytes.Buffer{}, fmt.Errorf("unsupported barcode type: %s", format)
 	}
 
+	logger = logger.With("type", format, "content", content, "width", width, "height", height, "padding", padding)
+	cacheKey := fmt.Sprintf("barcode:%s:%s:%d:%d:%d", format, content, width, height, padding)
+
 	if b.RedisClient != nil {
-		cachedBarcode, err := b.RedisClient.Get(ctx, fmt.Sprintf("barcode:%s:%s:%d:%d:%d", format, content, width, height, padding)).Result()
+		logger.Debugw("Checking cache for barcode", "key", cacheKey)
+		cachedBarcode, err := b.RedisClient.Get(ctx, cacheKey).Result()
 		if err == nil {
-			log.Printf("Cache hit for barcode:%s:%s:%d:%d", format, content, width, height)
+			logger.Infow("Barcode found in cache", "key", cacheKey)
 			buf := bytes.Buffer{}
 			buf.Write([]byte(cachedBarcode))
 			return buf, nil
@@ -73,6 +80,7 @@ func (b *DefaultBarcodeService) GenerateBarcode(format string, content string, w
 	bg := image.NewRGBA(image.Rect(0, 0, width, height))
 	white := color.RGBA{255, 255, 255, 255}
 	draw.Draw(bg, bg.Bounds(), &image.Uniform{white}, image.Point{}, draw.Src)
+	logger.Debug("Created white background")
 
 	// Calculate the new size for the barcode to fit within the padding
 	newWidth := width - 2*padding
@@ -81,24 +89,32 @@ func (b *DefaultBarcodeService) GenerateBarcode(format string, content string, w
 	// Scale the barcode to the new size
 	scaledCode, err := barcode.Scale(generatedCode, newWidth, newHeight)
 	if err != nil {
+		logger.Errorw("Failed to scale barcode", "error", err)
 		return bytes.Buffer{}, err
 	}
+	logger.Debug("Scaled barcode")
 
 	// Draw the barcode on top of the white background with padding
 	draw.Draw(bg, scaledCode.Bounds().Add(image.Point{padding, padding}), scaledCode, image.Point{}, draw.Over)
+	logger.Debug("Drew barcode on background")
 
 	var buf bytes.Buffer
 	err = png.Encode(&buf, bg)
 	if err != nil {
+		logger.Errorw("Failed to encode barcode to PNG", "error", err)
 		return bytes.Buffer{}, err
 	}
+	logger.Debug("Encoded barcode to PNG")
 
 	if b.RedisClient != nil {
-		err = b.RedisClient.Set(ctx, fmt.Sprintf("barcode:%s:%s:%d:%d", format, content, width, height), buf.String(), 10*time.Minute).Err()
+		err = b.RedisClient.Set(ctx, cacheKey, buf.String(), 10*time.Minute).Err()
+		logger.Debugw("Cached barcode", "key", cacheKey)
 		if err != nil {
+			logger.Errorw("Failed to cache barcode", "error", err)
 			return bytes.Buffer{}, err
 		}
 	}
+	logger.Info("Generated barcode")
 
 	return buf, nil
 }

services/converter.go

@@ -8,6 +8,7 @@ import (
 	"strconv"
 
 	"github.com/oxplot/papersizes"
+	"go.uber.org/zap"
 )
 
 type Converter interface {
@@ -16,92 +17,115 @@ type Converter interface {
 
 type GotenbergConverter struct {
 	BaseUrl string
+	Logger  *zap.SugaredLogger
 }
 
 func (g *GotenbergConverter) ToPdf(html string, pageSize string, landscape bool) ([]byte, error) {
+	logger := g.Logger.Named("ToPdf").With("page_size", pageSize, "landscape", landscape, "base_url", g.BaseUrl)
+
 	client := &http.Client{}
 	defer client.CloseIdleConnections()
+	logger.Debug("Created HTTP client")
 
 	body := &bytes.Buffer{}
 	writer := multipart.NewWriter(body)
 
 	part, err := writer.CreateFormFile("files", "index.html")
 	if err != nil {
+		logger.Errorw("Failed to create form file", "error", err)
 		return nil, err
 	}
 
 	_, err = part.Write([]byte(html))
 	if err != nil {
+		logger.Errorw("Failed to write to form file", "error", err)
 		return nil, err
 	}
 
 	size := papersizes.FromName(pageSize)
 	if size == nil {
+		logger.Errorw("Invalid page size", "size", pageSize)
 		return nil, fmt.Errorf("invalid page size: %s", pageSize)
 	}
 
 	err = writer.WriteField("paperWidth", strconv.Itoa(size.Width)+"mm")
 	if err != nil {
+		logger.Errorw("Failed to write paper width", "error", err)
 		return nil, err
 	}
 
 	err = writer.WriteField("paperHeight", strconv.Itoa(size.Height)+"mm")
 	if err != nil {
+		logger.Errorw("Failed to write paper height", "error", err)
 		return nil, err
 	}
 
 	err = writer.WriteField("landscape", strconv.FormatBool(landscape))
 	if err != nil {
+		logger.Errorw("Failed to write landscape", "error", err)
 		return nil, err
 	}
 
 	err = writer.WriteField("marginTop", "0")
 	if err != nil {
+		logger.Errorw("Failed to write margin top", "error", err)
 		return nil, err
 	}
 
 	err = writer.WriteField("marginBottom", "0")
 	if err != nil {
+		logger.Errorw("Failed to write margin bottom", "error", err)
 		return nil, err
 	}
 
 	err = writer.WriteField("marginLeft", "0")
 	if err != nil {
+		logger.Errorw("Failed to write margin left", "error", err)
 		return nil, err
 	}
 
 	err = writer.WriteField("marginRight", "0")
 	if err != nil {
+		logger.Errorw("Failed to write margin right", "error", err)
 		return nil, err
 	}
 
 	err = writer.WriteField("preferCssPageSize", "true")
 	if err != nil {
+		logger.Errorw("Failed to write prefer css page size", "error", err)
 		return nil, err
 	}
 
 	err = writer.Close()
 	if err != nil {
+		logger.Errorw("Failed to close writer", "error", err)
 		return nil, err
 	}
+	logger.Debug("Created form data")
 
+	logger.Debug("Creating HTTP request")
 	req, err := http.NewRequest("POST", g.BaseUrl+"/forms/chromium/convert/html", body)
 	if err != nil {
 		return nil, err
 	}
 	req.Header.Set("Content-Type", writer.FormDataContentType())
 
+	logger.Debug("Sending HTTP request")
 	resp, err := client.Do(req)
 	if err != nil {
+		logger.Errorw("Failed to send request", "error", err)
 		return nil, err
 	}
+	logger.Debug("Received HTTP response")
 
 	defer resp.Body.Close()
 	data := new(bytes.Buffer)
 	_, err = data.ReadFrom(resp.Body)
 	if err != nil {
+		logger.Errorw("Failed to read response body", "error", err)
 		return nil, err
 	}
 
+	logger.Debug("Returning PDF data")
 	return data.Bytes(), nil
 }

services/templater.go

@@ -7,6 +7,8 @@ import (
 	"fmt"
 	"html/template"
 	"strings"
+
+	"go.uber.org/zap"
 )
 
 type Templater interface {
@@ -17,6 +19,7 @@ type Templater interface {
 type DefaultTemplater struct {
 	BarcodeService BarcodeService
 	StaticService  StaticService
+	Logger         *zap.SugaredLogger
 }
 
 func idToEan13(id string, prefix string) (string, error) {
@@ -48,10 +51,13 @@ func (t *DefaultTemplater) GenerateBarcode(code string, format string, prefix st
 }
 
 func (t *DefaultTemplater) SelectSponsorImage(id int) (string, error) {
+	logger := t.Logger.Named("SelectSponsorImage")
 	sponsors, err := t.StaticService.ListFilesInStaticSubFolder("images/sponsors")
 	if err != nil {
+		logger.Errorw("Failed to list sponsors", "error", err)
 		return "", err
 	}
+	logger.Debugw("Selected sponsor", "sponsors", sponsors, "id", id, "selected", sponsors[id%len(sponsors)])
 	return t.StaticService.GetImage("sponsors/" + strings.TrimSuffix(sponsors[id%len(sponsors)], ".base64")), nil
 }
 

services/templates.go

@@ -3,8 +3,9 @@ package services
 import (
 	_ "embed"
 	"fmt"
-	"log"
 	"os"
+
+	"go.uber.org/zap"
 )
 
 type StaticService interface {
@@ -14,47 +15,55 @@ type StaticService interface {
 }
 
 type DefaultStaticService struct {
-	Cache map[string]string
+	Cache  map[string]string
+	Logger *zap.SugaredLogger
 }
 
 func (s *DefaultStaticService) GetTemplate(locale, templateName string) (string, error) {
+	logger := s.Logger.Named("GetTemplate").With("locale", locale, "template_name", templateName)
 
 	if s.Cache[locale+templateName] != "" {
-		log.Printf("returning cached template %s with locale %s", templateName, locale)
+		logger.Debugw("Template found in cache", "key", locale+templateName)
 		return s.Cache[locale+templateName], nil
 	}
 
 	content, err := os.ReadFile(fmt.Sprintf("static/templates/%s/%s.html", templateName, locale))
 	if content == nil || err != nil {
-		log.Printf("error reading template %s with locale %s: %v", templateName, locale, err)
+		logger.Errorw("Failed to read template", "error", err)
 		return "", err
 	}
 
 	s.Cache[locale+templateName] = string(content)
+	logger.Debugw("Saved template to cache", "key", locale+templateName)
 
 	return string(content), nil
 }
 
 func (s *DefaultStaticService) ListFilesInStaticSubFolder(folderName string) ([]string, error) {
+	logger := s.Logger.Named("ListFilesInStaticSubFolder").With("folder_name", folderName)
+
 	files, err := os.ReadDir(fmt.Sprintf("static/%s", folderName))
 	if err != nil {
-		log.Printf("error reading files from folder %s: %v", folderName, err)
+		logger.Errorw("Failed to list files", "error", err)
 		return nil, err
 	}
 	var images []string
 	for _, file := range files {
 		if file.IsDir() {
-			continue
+			logger.Debugw("Skipping directory", "file", file.Name())
 		}
 		images = append(images, file.Name())
 	}
+	logger.Debugw("Listed files", "files", images)
 	return images, nil
 }
 
 func (s *DefaultStaticService) GetImage(imageName string) string {
+	logger := s.Logger.Named("GetImage").With("image_name", imageName)
+
 	content, err := os.ReadFile("static/images/" + imageName + ".base64")
 	if content == nil || err != nil {
-		log.Printf("error reading image %s: %v", imageName, err)
+		logger.Errorw("Failed to read image", "error", err)
 		return ImageErrorBase64
 	}
 	return string(content)