Command is not executing properly (blocking) in Murano Package

[Gangadhar Sunkara]

We have a script under Resources/scrpits

In middle of the script we have to use a random string. So we used `cat /dev/urandom | tr -dc 'a-z0-9' | fold -w ${1:-12} | head -n 1`
line to get random string. If run this on Bash shell it returns the output immediately. Same command in package blocking the execution.

And the output of `ps -Af` at blocking time is :

root 11652 11651 99 10:46 ? 00:00:02 cat /dev/urandom
root 11653 11651 6 10:46 ? 00:00:00 tr -dc a-z0-9
root 11654 11651 1 10:46 ? 00:00:00 fold -w 12

which is missing `head -n 1` process.

Attached the package which produces above case.

Thanks.

[Stan Lagun (slagun)]

Dmytro, can you validate the bug?

[Dmytro Dovbii (ddovbii)]

Unfortunately, this is not a bug of murano. Murano-agent uses `subprocess` module in order to execute shell scripts [1]
I tried to run the same command locally without murano-agent, but just using subprocess module and ipython:

```
import subprocess
cmd = "cat /dev/urandom | tr -dc 'a-z0-9' | fold -w ${1:-12} | head -n 1"
subprocess.call(cmd, shell=True)

```
and faced this the same problem - hanging of execution. I also tried to use another modules such as `os` or `pexpect` and tried to experiment with different parameters of subprocess functions, but allways saw this behaviour. So, looks like this we can't fix it right now. Please, use another methods of generating a random strings.

1. https://github.com/openstack/murano-agent/blob/master/muranoagent/executors/application/__init__.py#L55-L62

[Stan Lagun (slagun)]

Fixed by https://review.openstack.org/#/c/295833/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/mitaka
Review: https://review.openstack.org/295850

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/liberty
Review: https://review.openstack.org/295852

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/kilo
Review: https://review.openstack.org/295853

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/295833
Committed: https://git.openstack.org/cgit/openstack/murano-agent/commit/?id=75712716ba52e945965ab588620e8d9d26795c40
Submitter: Jenkins
Branch: master

commit 75712716ba52e945965ab588620e8d9d26795c40
Author: Stan Lagun <email address hidden>
Date: Tue Mar 22 16:47:49 2016 +0300

    Restores SIGPIPE on script processes

    There is an issue https://bugs.python.org/issue1652
    in Python 2.7 which was resolved in Py3.

    By default Python sets SIGPIPE to SIG_IGN on startup, because
    it prefers to check every write and raise an IOError exception rather
    than taking SIGPIPE. This is all well and good for Python itself.
    However, non-Python Unix subprocesses generally expect to have
    SIGPIPE set to the default action, since that's what will happen if
    they're started from a normal shell.

    As a result scripts with piping that is terminated in reverse chain
    order are never exit.

    See more info here:
    http://www.enricozini.org/blog/2009/debian/python-pipes/

    Closes-Bug: #1524347
    Change-Id: Ia015e7fd46912f6a0be97a6b9c297f8d14fd3f7c

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/295853
Committed: https://git.openstack.org/cgit/openstack/murano-agent/commit/?id=75e7e046950464a9dfc1afafeb86fc0b1afe6ce2
Submitter: Jenkins
Branch: stable/kilo

commit 75e7e046950464a9dfc1afafeb86fc0b1afe6ce2
Author: Stan Lagun <email address hidden>
Date: Tue Mar 22 16:47:49 2016 +0300

    Restores SIGPIPE on script processes

    There is an issue https://bugs.python.org/issue1652
    in Python 2.7 which was resolved in Py3.

    By default Python sets SIGPIPE to SIG_IGN on startup, because
    it prefers to check every write and raise an IOError exception rather
    than taking SIGPIPE. This is all well and good for Python itself.
    However, non-Python Unix subprocesses generally expect to have
    SIGPIPE set to the default action, since that's what will happen if
    they're started from a normal shell.

    As a result scripts with piping that is terminated in reverse chain
    order are never exit.

    See more info here:
    http://www.enricozini.org/blog/2009/debian/python-pipes/

    Closes-Bug: #1524347
    Change-Id: Ia015e7fd46912f6a0be97a6b9c297f8d14fd3f7c

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/295852
Committed: https://git.openstack.org/cgit/openstack/murano-agent/commit/?id=0bbfed3bf40192f34607c69c0a46301e81a643be
Submitter: Jenkins
Branch: stable/liberty

commit 0bbfed3bf40192f34607c69c0a46301e81a643be
Author: Stan Lagun <email address hidden>
Date: Tue Mar 22 16:47:49 2016 +0300

    Restores SIGPIPE on script processes

    There is an issue https://bugs.python.org/issue1652
    in Python 2.7 which was resolved in Py3.

    By default Python sets SIGPIPE to SIG_IGN on startup, because
    it prefers to check every write and raise an IOError exception rather
    than taking SIGPIPE. This is all well and good for Python itself.
    However, non-Python Unix subprocesses generally expect to have
    SIGPIPE set to the default action, since that's what will happen if
    they're started from a normal shell.

    As a result scripts with piping that is terminated in reverse chain
    order are never exit.

    See more info here:
    http://www.enricozini.org/blog/2009/debian/python-pipes/

    Closes-Bug: #1524347
    Change-Id: Ia015e7fd46912f6a0be97a6b9c297f8d14fd3f7c

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/295850
Committed: https://git.openstack.org/cgit/openstack/murano-agent/commit/?id=8738324d9c70675b874256e1f07ebb29e34688b8
Submitter: Jenkins
Branch: stable/mitaka

commit 8738324d9c70675b874256e1f07ebb29e34688b8
Author: Stan Lagun <email address hidden>
Date: Tue Mar 22 16:47:49 2016 +0300

    Restores SIGPIPE on script processes

    There is an issue https://bugs.python.org/issue1652
    in Python 2.7 which was resolved in Py3.

    By default Python sets SIGPIPE to SIG_IGN on startup, because
    it prefers to check every write and raise an IOError exception rather
    than taking SIGPIPE. This is all well and good for Python itself.
    However, non-Python Unix subprocesses generally expect to have
    SIGPIPE set to the default action, since that's what will happen if
    they're started from a normal shell.

    As a result scripts with piping that is terminated in reverse chain
    order are never exit.

    See more info here:
    http://www.enricozini.org/blog/2009/debian/python-pipes/

    Closes-Bug: #1524347
    Change-Id: Ia015e7fd46912f6a0be97a6b9c297f8d14fd3f7c

[Doug Hellmann (doug-hellmann)]

This issue was fixed in the openstack/murano-agent 3.0.0.0b1 development milestone.

[Doug Hellmann (doug-hellmann)]

This issue was fixed in the openstack/murano-agent 2015.1.1 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/murano-agent 2015.1.1 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/murano-agent 2.0.0 release.