updateandreadFile.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
)

type content struct {
	Count int
}

func checkFileExists(name string) bool {
	_, err := os.Stat(name)
	if err != nil {
		return os.IsExist(err)
	}
	return true
}

func updateFileContent(name string) error {
	fBlob, err := ioutil.ReadFile(name)
	if err != nil {
		fmt.Println(name, "ReadFile Error", err)
	}
	fmt.Println(string(fBlob))

	var fContent content
	err = json.Unmarshal(fBlob, &fContent)
	if err != nil {
		fmt.Println("Error Unmarshaling data", err)
		return err
	}

	fContent.Count++
	fBlob, err = json.Marshal(fContent)
	if err != nil {
		fmt.Println("Error Marshaling data", err)
		return err
	}
	err = ioutil.WriteFile(name, fBlob, 0666)
	if err != nil {
		fmt.Println(name, "Write File Error", err)
	}
	return nil
}

func createFileContent(name string) error {
	fh, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE, 0666)
	defer fh.Close()
	if err != nil {
		fmt.Println(name, "ReadFile Error", err)
	}

	fContent := content{Count: 1}
	fBlob, err := json.Marshal(fContent)
	if err != nil {
		fmt.Println("Error Marshaling data", err)
		return err
	}
	_, err = fh.Write(fBlob)
	if err != nil {
		fmt.Println(name, "Write File Error", err)
	}

	return nil
}

func main() {
	var err error
	names := []string{"file-1", "file-2", "file-1", "file-2", "file-3", "file-3"}

	for _, name := range names {
		isFileExists := checkFileExists(name)
		fmt.Println(name, "Exists:", isFileExists)

		if isFileExists {
			err = updateFileContent(name)
			if err != nil {
				fmt.Println("Error updating file", err)
			}
		} else {
			err = createFileContent(name)
			if err != nil {
				fmt.Println("Error creating file", err)
			}
		}
	}

	// Delete all the files that were created
	for _, name := range names {
		isFileExists := checkFileExists(name)
		if isFileExists {
			err = os.Remove(name)
			if err != nil {
				fmt.Println("Error Removing the file", name, err)
			}
		}
	}

}