二郎心的用法

Question

应该

如何使用心脏来保持应用程序的活动？

假设我有一个应用程序 X，如果我只调用以下内容，它是否会受到监控：

erl -boot X -heart -env HEART_BEAT_TIMEOUT 30 -detached

？

Answer 1

是的，这将自动启动一个监控节点的心脏进程。请参阅心脏文档。

更新：是的，渐近线是正确的。您还需要一个HEART_COMMAND环境变量来指示重新启动节点时要执行的操作。

Answer 2

http://www.erlang.org/doc/man/heart.html

This modules contains the interface to the heart process. heart
sends periodic heartbeats to an external port program, which is
also named `heart`. The purpose of the heart port program is to
check that the Erlang runtime system it is supervising is still
running. If the port program has not received any heartbeats within
`HEART_BEAT_TIMEOUT` seconds (default is 60 seconds), the system
can be rebooted. Also, if the system is equipped with a hardware
watchdog timer and is running Solaris, the watchdog can be used to
supervise the entire system.
<snip>
If the system should be rebooted because of missing heart-beats, or
a terminated Erlang runtime system, the environment variable
HEART_COMMAND has to be set before the system is started. If this
variable is not set, a warning text will be printed but the system
will not reboot.

现在我有一个Makefile，里面有一个语句，它将为我运行erl -heart ...。 当我执行它时，这里是进程列表：

ubuntu    3814  3579  3814  3579  0 22:03 pts/0    00:00:00           make webstart
ubuntu    3829  3814  3814  3579 25 22:03 pts/0    00:00:01             /usr/local/lib/erlang/erts-5.8.3/bin/beam.smp -K true -A 5
ubuntu    3848  3829  3848  3848  0 22:03 ?        00:00:00               heart -pid 3829

当我杀死PID 3829时，以下输出出现在Erlang shell中：

heart: Wed May 18 22:04:09 2011: Erlang has closed.
heart: Wed May 18 22:04:09 2011: Would reboot. Terminating.
make: *** [webstart] Terminated

很明显，我需要将HEART_COMMAND设置为某种重新启动语句，然后心脏将按要求执行。 AFAIK，鉴于文档中的描述，heart 并不是简单地在崩溃时重新启动 Erlang VM;这听起来像是 Erlang 主管应该为你做的事情，但我可能是错的。

（当然，你可以得到HEART_COMMAND来重新启动你的 Erlang 程序）。