examples/bin/verify-default-ports

#!/usr/bin/env perl

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# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
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#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
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# specific language governing permissions and limitations
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use strict;
use warnings;
use Socket;

sub try_bind {
  my ($port, $addr) = @_;

  socket(my $sock, PF_INET, SOCK_STREAM, Socket::IPPROTO_TCP) or die "socket: $!";
  setsockopt($sock, SOL_SOCKET, SO_REUSEADDR, pack("l", 1)) or die "setsockopt: $!";
  if (!bind($sock, sockaddr_in($port, $addr))) {
    print STDERR <<"EOT";
Cannot start up because port $port is already in use.

If you need to change your ports away from the defaults, check out the
configuration documentation:

  https://druid.apache.org/docs/latest/configuration/index.html

If you believe this check is in error, or if you have changed your ports away
from the defaults, you can skip this check using an environment variable:

  export DRUID_SKIP_PORT_CHECK=1

EOT
    exit 1;
  }
  shutdown($sock, 2);
}

my $skip_var = $ENV{'DRUID_SKIP_PORT_CHECK'};
if ($skip_var && $skip_var ne "0" && $skip_var ne "false" && $skip_var ne "f") {
  exit 0;
}

my @ports = @ARGV;
if (!@ports) {
  @ports = (1527, 2181, 8081, 8082, 8083, 8090, 8091, 8100, 8200, 8888);
}

for my $port (@ports) {
  try_bind($port, INADDR_ANY);
  try_bind($port, inet_aton("127.0.0.1"));
}