Base project

internal/csv/helper.go

@@ -0,0 +1,54 @@
+package csv
+
+import (
+	"encoding/csv"
+	"os"
+
+	"go.uber.org/fx"
+	"go.uber.org/zap"
+)
+
+type Helper struct {
+	fx.In
+	csvFile   *os.File
+	csvWriter *csv.Writer
+	logger    *zap.Logger
+}
+
+func NewHelper(lc fx.Lifecycle, logger *zap.Logger) *Helper {
+	csvFile, err := os.OpenFile("mqtt-logs.csv", os.O_CREATE|os.O_RDWR|os.O_APPEND, 0644)
+	if err != nil {
+		logger.Fatal("error opening csv file", zap.Error(err))
+	}
+
+	csvWriter := csv.NewWriter(csvFile)
+
+	return &Helper{
+		csvFile:   csvFile,
+		csvWriter: csvWriter,
+		logger:    logger,
+	}
+}
+
+func (h *Helper) AddEntry(date string, topic string, message string) error {
+	record := []string{date, topic, message}
+	if err := h.csvWriter.Write(record); err != nil {
+		h.logger.Error("error writing to csv file", zap.Error(err))
+		return err
+	}
+
+	h.csvWriter.Flush()
+
+	return nil
+}
+
+func (h *Helper) Close() error {
+	h.csvWriter.Flush()
+
+	if err := h.csvFile.Close(); err != nil {
+		h.logger.Error("error closing csv file", zap.Error(err))
+		return err
+	}
+
+	return nil
+}

internal/csv/init.go

@@ -0,0 +1,33 @@
+package csv
+
+import (
+	"encoding/csv"
+	"io"
+	"os"
+
+	"go.uber.org/zap"
+)
+
+func InitializeHeader(logger *zap.Logger) {
+	csvFile, err := os.OpenFile("mqtt-logs.csv", os.O_CREATE|os.O_RDWR|os.O_APPEND, 0644)
+	if err != nil {
+		logger.Fatal("error opening csv file", zap.Error(err))
+	}
+	defer csvFile.Close()
+
+	r := csv.NewReader(csvFile)
+	w := csv.NewWriter(csvFile)
+	record, err := r.Read()
+
+	if err == io.EOF {
+		w.Write([]string{"Date (UTC)", "Topic", "Message"})
+		w.Flush()
+	} else if err != nil {
+		logger.Fatal("error initializing csv file", zap.Error(err))
+	} else if record[0] == "Date (UTC)" && record[1] == "Topic" && record[2] == "Message" {
+		return
+	} else {
+		logger.Fatal("First row of csv file is not as expected. Please make sure the file is in the correct format.")
+	}
+
+}