[erlang-questions] "detached VM" vs "VM under screen"

[Garrett Smith]

On Fri, Jan 6, 2012 at 12:58 PM, dmitry kolesnikov
<dmkolesnikov@REDACTED> wrote:
> Hello,
> Recently I meet issue with run_erl and heart. Heart monitors only beam
> process, if run_erl dies then to_erl cannot access console. I am
> planning to rollback into remote shell approach.

This is not true. You may be seeing something environment specific or
have a configuration issue.

FWIW, I've used run_erl in a large variety of production settings and
would strongly recommend it.

Here's what I see on Linux R14B04:

$ mkdir /tmp/test
$ pgrep beam && pgrep run_erl # confirm no running Erlang procs
$ HEART_COMMAND="run_erl -daemon /tmp/test/ /tmp/test/ 'erl -heart'"
run_erl -daemon /tmp/test/ /tmp/test/ "erl -heart"
$ pgrep beam && pgrep run_erl
8618
8616
$ echo "1 + 1." | to_erl /tmp/test/
Attaching to /tmp/test/erlang.pipe.3 (^D to exit)

[EOF]
$ tail -n3 /tmp/test/erlang.log.1
1> 1 + 1.
2
$ pkill run_erl
$ pgrep beam && pgrep run_erl
8703
8701
$ echo "2 + 2." | to_erl /tmp/test/
Attaching to /tmp/test/erlang.pipe.4 (^D to exit)

[EOF]
$ tail -n3 /tmp/test/erlang.log.1
1> 2 + 2.
4
$ pkill beam
$ pgrep beam && pgrep run_erl
8753
8751
$ echo "4 + 4." | to_erl /tmp/test/
Attaching to /tmp/test/erlang.pipe.5 (^D to exit)

[EOF]
$ tail -n3 /tmp/test/erlang.log.1
1> 4 + 4.
8
$ pkill heart
$ pgrep beam && pgrep run_erl