ulidparse: add thingy

ulidparse/main.go

···
+package main
+
+import (
+	"bufio"
+	"context"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"os/signal"
+
+	"github.com/oklog/ulid/v2"
+)
+
+func main() {
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer cancel()
+	if err := realMain(
+		ctx,
+		os.Stdin,
+		os.Stdout,
+		os.Stderr,
+		os.Args,
+	); err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+		os.Exit(1)
+	}
+}
+
+func realMain(_ context.Context, stdin io.Reader, stdout io.Writer, stderr io.Writer, osargs []string) error {
+	fs := flag.NewFlagSet("ulidparse", flag.ExitOnError)
+	flagSort := fs.Bool("sort", false, "sort the output")
+	fs.SetOutput(stderr)
+
+	fs.Usage = func() {
+		fmt.Fprintf(fs.Output(), "Usage: %s [options] <query> [<file>]\n", fs.Name())
+		fs.PrintDefaults()
+	}
+
+	if err := fs.Parse(osargs[1:]); err != nil {
+		return err
+	}
+
+	scanner := bufio.NewScanner(stdin)
+
+	var goterr bool
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		uu, err := ulid.Parse(line)
+		if err != nil {
+			goterr = true
+			fmt.Fprintf(stderr, "error: %v\n", err)
+		}
+
+		if !*flagSort {
+			fmt.Fprintf(stdout, "%s	%v\n", line, ulid.Time(uu.Time()).UTC())
+			continue
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return err
+	}
+
+	if goterr {
+		return fmt.Errorf("some lines failed to parse")
+	}
+
+	return nil
+}