package main

import (
	"context"
	"fmt"
	"io/fs"
	"os"
	"runtime/debug"

	"github.com/containers/image/v5/docker"
	"github.com/containers/image/v5/types"
	"github.com/containers/image/v5/version"
	"github.com/sirupsen/logrus"
)

func inspectImage(ref types.ImageReference) error {
	ctx := context.Background()
	src, err := ref.NewImageSource(ctx, nil)
	if err != nil {
		return err
	}
	defer src.Close()
	_, _, err = src.GetManifest(ctx, nil)
	return err
}

func listOpenFiles() {
	fd, err := os.Open("/dev/fd")
	if err != nil {
		panic(err)
	}
	defer fd.Close()
	entries, err := fd.ReadDir(-1)
	fmt.Printf("%d open files:\n", len(entries))
	for _, e := range entries {
		fmt.Printf("\t%s\n", fs.FormatDirEntry(e))
	}
}

func main() {
	debug.SetTraceback("all")
	c := make(chan struct{})
	go func() { <-c }() // A sanity check to show the traceback does list all goroutines
	fmt.Printf("c/image version: %s\n", version.Version)
	logrus.SetLevel(logrus.DebugLevel)
	ref, err := docker.ParseReference("//docker.io/library/none:latest")
	if err != nil {
		panic(err)
	}
	for i := 0; i < 10; i++ {
		_ = inspectImage(ref)
	}
	listOpenFiles()
	panic("listing goroutines:")
}