我正在使用一个简单的基于Mojolicious::Lite
的服务器,该服务器包含一个websocket端点。
我想处理一些终止信号来优雅地终止websocket连接,并避免客户端(Java应用程序)中的异常。
我尝试定义信号处理程序,就像我以前使用HTTP::Daemon
定义以前的服务器一样。
问题在于它们似乎被忽略了。也许是在Mojolicious层中重新定义的,但我还没有找到任何参考。
我希望看到我的终止消息,但是不会发生
[Mon Mar 23 14:01:28 2020] [info] Listening at "http://*:3000"
Server available at http://127.0.0.1:3000
^C # <-- i want to see my signal received message here if type Ctrl-c
当服务器在终端中处于前台时,我将通过输入SIGINT
直接发送Ctrl-C
,并且我可以使用以下命令优雅地终止服务器(例如,以cron或其他无显示方式启动服务器) kill <pid>
。
在以前的某些服务器中,我尝试通过处理以下内容来使其表现出美感:
HUP
被劫持的信号如今用于重新加载配置SIGINT
Ctrl-C SIGQUIT
Ctrl-\ SIGABRT
,例如库异常终止SIGTERM
外部终止请求-“友好” kill
(反对残酷的kill -9
TSTP
用Ctrl-Z暂停CONT
或fg
从Ctrl-Z恢复时bg
所有这些处理程序均允许使用清理资源正常退出,以确保数据一致性或在外部更改后重新加载配置或数据模型,具体取决于程序和需求。
我找到了Mojo::IOLoop::Signal
包,即“非阻塞信号处理程序”,但这似乎是另一回事。不对吗?
这是我的简化代码(以简单的perl ws_store_test.pl daemon
运行):
文件ws_store_test.pl
# Automatically enables "strict", "warnings", "utf8" and Perl 5.10 features
use Mojolicious::Lite;
my $store = {};
my $ws_clients = {};
sub terminate_clients {
for my $peer (keys %$ws_clients){
$ws_clients->{$peer}->finish;
}
}
$SIG{INT} = sub {
say "SIGINT"; # to be sure to display something
app->log->info("SIGINT / CTRL-C received. Leaving...");
terminate_clients;
};
$SIG{TERM} = sub {
say "SIGTERM"; # to be sure to display something
app->log->info("SIGTERM - External termination request. Leaving...");
terminate_clients;
};
# this simulates a change on datamodel and notifies the clients
sub update_store {
my $t = localtime time;
$store->{last_time} = $t;
for my $peer (keys %$ws_clients){
app->log->debug(sprintf 'notify %s', $peer);
$ws_clients->{$peer}->send({ json => $store
});
}
}
# Route with placeholder - to test datamodel contents
get '/:foo' => sub {
my $c = shift;
my $foo = $c->param('foo');
$store->{$foo}++;
$c->render(text => "Hello from $foo." . (scalar keys %$store ? " already received " . join ', ', sort keys %$store : "") );
};
# websocket service with optional parameter
websocket '/ws/tickets/*id' => { id => undef } => sub {
my $ws = shift;
my $id = $ws->param('id');
my $peer = sprintf '%s', $ws->tx;
app->log->debug(sprintf 'Client connected: %s, id=%s', $peer, $id);
$ws_clients->{$peer} = $ws->tx;
$store->{$id} = {};
$ws->on( message => sub {
my ($c, $message) = @_;
app->log->debug(sprintf 'WS received %s from a client', $message);
});
$ws->on( finish => sub {
my ($c, $code, $reason) = @_;
app->log->debug(sprintf 'WS client disconnected: %s - %d - %s', $peer, $code, $reason);
delete $ws_clients->{$peer};
});
};
plugin Cron => ( '* * * * *' => \&update_store );
# Start the Mojolicious command system
app->start;
答案 0 :(得分:3)
SIGINT和SIGTERM处理程序在服务器启动时重新定义。在morbo中是:
local $SIG{INT} = local $SIG{TERM} = sub {
$self->{finished} = 1;
kill 'TERM', $self->{worker} if $self->{worker};
};
在Mojo::Server::Daemon中,这是:
local $SIG{INT} = local $SIG{TERM} = sub { $loop->stop };
如果您在顶级重新定义SIGINT / SIGTERM的处理程序,则这些local
将覆盖它们。相反,我建议在before_dispatch
钩子中重新定义一次。例如:
sub add_sigint_handler {
my $old_int = $SIG{INT};
$SIG{INT} = sub {
say "SIGINT"; # to be sure to display something
app->log->info("SIGINT / CTRL-C received. Leaving...");
terminate_clients;
$old_int->(); # Calling the old handler to cleanly exit the server
}
}
app->hook(before_dispatch => sub {
state $unused = add_sigint_handler();
});
在这里,我使用state
来确保仅对add_sigint_handler
进行一次评估(因为如果对其进行了多次评估,则$old_int
在第一个评估之后将没有正确的值时间)。另一种书写方式可能是:
my $flag = 0;
app->hook(before_dispatch => sub {
if ($flag == 0) {
add_sigint_handler();
$flag = 1;
}
});
或者,
app->hook(before_dispatch => sub {
state $flag = 0;
if ($flag == 0) {
add_sigint_handler();
$flag = 1;
}
});