measure script for SMTP connection establish times

smtp-connect-bench.pl

#!/usr/bin/perl
# smtp-connect-bench.pl [HOSTNAME|IPADDR]
# SMTP 接続の速度を確認する

use strict;
use warnings;
use Net::SMTP;
use Time::HiRes qw(time sleep); # ミリ秒化
use constant WAIT_SECONDS => 15;
use constant SMTP_TIMEOUT_SECONDS => 120;

$| = 1; # flush output buffer: 改行無し print 迅速化

my $hostname = shift || '127.0.0.1';

while (1) {
    print "connection start... ";
    local $@;
    my $take_seconds = measure_time( sub {
        my $smtp = Net::SMTP->new($hostname, Timeout => SMTP_TIMEOUT_SECONDS);
        # $smtp->hello("localhost");
        $smtp->quit();
    });
    printf "take %.2f seconds\n", $take_seconds;
    if ( $@ ) { print "  Exception: $@\n"; }
    sleep WAIT_SECONDS; # 過度な連続接続防止
}

# measure_time( sub { ... } )
# 第1引数のコードリファレンスを実行した秒数を返す
# 例外変数 $@ は上流で初期化する
sub measure_time {
    my $code = shift;
    my $start_time = time;
    eval { $code->(); };
    my $end_time = time;
    return $end_time - $start_time;
}