the-bastion/bin/plugin/open/alive

#! /usr/bin/env perl
# vim: set filetype=perl ts=4 sw=4 sts=4 et:
use common::sense;
use Time::HiRes ();

use File::Basename;
use lib dirname(__FILE__) . '/../../../lib/perl';
use OVH::Result;
use OVH::Bastion;
use OVH::Bastion::Plugin qw( :DEFAULT help );

my $remainingOptions = OVH::Bastion::Plugin::begin(
    argv     => \@ARGV,
    header   => "ping until host is alive",
    options  => {},
    helptext => <<'EOF',
Ping a host and exit as soon as it answers

This command can be used to monitor a host that is expected to go back online soon.
Note that if you want to ssh to it afterwards, you can simply use the ``--wait`` main option.

Usage: --osh SCRIPT_NAME [--host] HOSTNAME

  --host HOSTNAME  hostname or IP to ping
EOF
);

# be nice and try to guessify a user@host as first param
# if user said --osh alive usah@mymachine.example.org
if (    not $host
    and not $ip
    and not $user
    and ref $remainingOptions eq 'ARRAY'
    and @$remainingOptions == 1
    and $remainingOptions->[0] =~ /^([a-zA-Z0-9_-]+\@)?([a-zA-Z0-9][a-zA-Z0-9.-]{1,})$/)
{
    $user = $1;
    $host = $2;
    $user =~ s/\@$//;
}

#
# code
#
my $fnret;

if (not $host) {
    help();
    osh_exit 'ERR_MISSING_PARAMETER', "Missing required host parameter";
}

osh_info "Waiting for $host to be alive...";
my $startedat = Time::HiRes::gettimeofday();
my $firstLoop = 1;
my @command   = qw{ fping -- };
push @command, $host;
while (1) {
    $fnret = OVH::Bastion::execute(cmd => \@command, noisy_stdout => 1, noisy_stderr => 1);
    if ($fnret->err eq 'ERR_EXEC_FAILED') {
        if ($firstLoop) {
            # maybe fping doesn't work, fallback to ping
            @command = qw{ ping -c 1 -w 1 -- };
            push @command, $host;
            $firstLoop = 0;
            next;    # restart the loop to exec ping
        }
        osh_exit $fnret;    # we tried both ping and fping :(
    }
    $fnret or osh_exit $fnret;
    if ($fnret->value->{'sysret'} == 0) {
        my $delay = int(Time::HiRes::gettimeofday() - $startedat);
        osh_info "Alive after waiting for $delay seconds, exiting!";
        osh_ok {waited_for => $delay + 0};
    }
    sleep 1;
}

osh_exit 'ERR_INTERNAL';