perl实现多进程的操作

场景： 我们需要访问若干机器进行状态检查，文件拷贝之类的操作。

分析：我们可以使用循环的方式来进行逐个操作。如果每个操作耗时很短的话还可以接受。假如每个操作耗时很长，这样单个处理的方式就显得效率低下。因为每个节点的操作是相互独立的，我们可以使用多进程的方式并行处理。为了防止本地机器的资源耗费很大，我们又期望对并行的个数进行限制。在操作过程中，还可能出现操作卡住的情况，因此我们还需要限制操作的时间，如果超过这个限定的时间之后我们就认为操作失败，可能需要人工干预。

实现： 基于上述描述，我们可以用perl来实现上述功能。

use warnings;use strict;use File::Spec;use FindBin qw($Bin);use Net::OpenSSH;use POSIX ":sys_wait_h";#限制同时操作的节点数目my $host_number_simultaneity = 6;#设置操作的最大时间my $install_seconds_limiation = 1800;#机器的登陆用户名和密码my $login_user = "root";my $login_passwd = "312";my $ssh_ops = {user => $login_user, password => $login_passwd, master_opts => [-o => "UserKnownHostsFile=/dev/null", -o => "StrictHostKeyChecking=no"]};#当前目录下记录操作的日志文件my $log_file='install.log';open(LOG_FILENAME, '>', "$log_file") || die "\nCan't open log file $log_file to record results of opeation !! ";select LOG_FILENAME;$| = 1;chomp(my $time_stamp=`date`);print "step 0: operation begin at $time_stamp\n";#获取操作节点的IP地址，用户这里可以自行处理my @all_host_ip = qw/192.168.10.10 192.168.10.12 192.168.10.14/;say LOG_FILENAME "all the hosts ip are as follows: @all_host_ip";my $host_number_total = @all_host_ip;my $host_number_ongoing = 0;my $host_number_finished = 0;my $host_number_timeout = 0;# (key : pid, value : host ip)my %pid_to_host = ();# (key : pid, value : start time-seconds)my %pid_to_start_time = ();$SIG{CHLD} = sub{$host_number_ongoing--};say LOG_FILENAME "there are $host_number_total hosts in all";for (my $index=0; $index<$host_number_total;$index++) {    my $pid = fork();    if ( !defined($pid) ) {        say LOG_FILENAME "Error in fork: $!. This is going to deal with host $all_host_ip[$index]";        print "Error in fork: $!. This is going to deal with host $all_host_ip[$index]\n";        exit 1;    }    if ( $pid == 0 ) {        say LOG_FILENAME "index: $index -- This is going to begin operation on host $all_host_ip[$index]";        print "index: $index -- This is going to begin operation on host $all_host_ip[$index]\n";        #对每个节点进行操作处理        &operation_host($all_host_ip[$index]);        say LOG_FILENAME "index: $index -- This is the end of installation on host $all_host_ip[$index]";        exit 0;    }    $pid_to_host{$pid} = $all_host_ip[$index];    $pid_to_start_time{$pid} = time;    $host_number_ongoing++;    #如果正在操作的节点数量超过限制的数量，就等待30秒，再检查是否有操作完毕    while ( $host_number_ongoing >= $host_number_simultaneity ) {        sleep(30);    }   }my $collect_pid;while ( ($host_number_finished+$host_number_timeout) != $host_number_total ) {    if ( ($collect_pid = waitpid(-1,WNOHANG)) > 0 ) {        #操作结束之后，从哈希中将记录删除        $host_number_finished++;        chomp($time_stamp=`date`);        say LOG_FILENAME "operation on host $pid_to_host{$collect_pid} finished at $time_stamp ";        if ( exists $pid_to_host{$collect_pid} ) {            delete $pid_to_host{$collect_pid};        }        if ( exists $pid_to_start_time{$collect_pid} ) {            delete $pid_to_start_time{$collect_pid};        }    }    #检查没有结束的操作是否超时    my $current_time = time;    $host_number_timeout = 0;    while ( my ($key, $value) = each %pid_to_start_time ) {        if ( ($current_time - $pid_to_start_time{$key}) >= $install_seconds_limiation ) {            say LOG_FILENAME "operation on host $pid_to_host{$key} are time out yet";            $host_number_timeout++;        }    }    chomp($time_stamp=`date`);    say LOG_FILENAME "sleep 30s to check again...current time: $time_stamp";    print "sleep 30s to check again...current time: $time_stamp\n";    sleep(30);}# 将超时的节点ip信息打印处理if ( $host_number_total > 0 ) {    while ( my ($key, $value) = each %pid_to_host ) {        say LOG_FILENAME "operation on host $pid_to_host{$key} are time out finally!!";        print "operation on host $pid_to_host{$key} are time out finally!!\n";    }}close LOG_FILENAME;exit 0;