libyear.go

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"time"
)

type module struct {
	Path    string
	Version string
	Time    string
	Update  struct {
		Path    string
		Version string
		Time    string
	}
}

func main() {
	var fp string
	if len(os.Args) >= 2 {
		fp = os.Args[1]
	} else {
		fp = "go.mod"
	}

	cmd := exec.Command("go", "list", "-m", "-u", "-json", "-modfile", fp, "all")

	b, err := cmd.CombinedOutput()
	if err != nil {
		log.Fatal(err)
	}
	dec := json.NewDecoder(bytes.NewReader(b))
	minutes := float64(0)
	for {
		var mod module

		err := dec.Decode(&mod)
		if err == io.EOF {
			// all done
			break
		}
		if err != nil {
			log.Fatal(err)
		}

		if mod.Update.Time != "" {
			newTime, err := time.Parse(time.RFC3339, mod.Update.Time)
			if err != nil {
				log.Fatal(err)
			}
			currentTime, err := time.Parse(time.RFC3339, mod.Time)
			if err != nil {
				log.Fatal(err)
			}

			d := newTime.Sub(currentTime)
			minutes += d.Minutes()
		}
	}

	fmt.Println(minutes / (365 * 24 * 60))

}