Filename, date

Consider a Go program that is run each day, and outputs a report. We want to place its output in a file name that contains the current day.

With time.Now, we can get the current time. And we can convert this to a string with the Format func. We can even provide a pattern to specify delimiter chars.

An example

Consider this Go example program. We introduce a GetFilenameDate method, and this returns a file name with the current date.

Info Now returns the current time—it will change each day the program is run, and is always current.

Here We pass the full file name with its path to the ioutil.WriteFile func. Check the target folder, and the file will exist.

package main

import (
    "fmt"
    "io/ioutil"
    "time"
)

func GetFilenameDate() string {
    // Use layout string for time format.
    const layout = "01-02-2006"
    // Place now in the string.
    t := time.Now()
    return "file-" + t.Format(layout) + ".txt"
}

func main() {
    name := GetFilenameDate()
    fmt.Println("Name:", name)
    ioutil.WriteFile("C:\\programs\\" + name, []byte("Contents"), 0)
}
Name: file-06-18-2020.txt

A utility method

Consider a Go program that downloads server logs and collects usage stats. It can be run once per day, and output its result in a file.

And With the GetFilenameDate func, we could place the program's output in a file with a useful name.

A summary

The important part here is to use Format on the time instance to get a string containing the date. Then we can create the full path from that file name.