PR#5: Add support to run commands in background - python-pytest-multihost

python-pytest-multihost

#5 Add support to run commands in background

Merged 6 years ago by spoore. Opened 6 years ago by mrniranjan.

mrniranjan/python-pytest-multihost master into master

Add support to run commands in background

Niranjan M.R • 6 years ago

34529cd

pytest_multihost/host.py

file modified

+5 -3

		`@@ -201,7 +201,7 @@`

		`def run_command(self, argv, set_env=True, stdin_text=None,`
		`log_stdout=True, raiseonerr=True,`
		`- cwd=None):`
		`+ cwd=None, bg=False):`
		`"""Run the given command on this host`

		`Returns a Command instance. The command will have already run in the`
		`@@ -218,6 +218,7 @@`
		`:param raiseonerr: If true, an exception will be raised if the command`
		`does not exit with return code 0`
		`:param cwd: The working directory for the command`
		`+ :param bg: If True, runs command in background`
		`"""`
		`command = self.transport.start_shell(argv, log_stdout=log_stdout)`
		`# Set working directory`
		`@@ -247,11 +248,12 @@`
		`if stdin_text:`
		`command.stdin.write(stdin_text)`
		`command.stdin.flush()`
		`-`
		`- command.wait(raiseonerr=raiseonerr)`
		`+ if not bg:`
		`+ command.wait(raiseonerr=raiseonerr)`
		`return command`


		`+`
		`class Host(BaseHost):`
		`"""A Unix host"""`
		`command_prelude = 'set -e\n'`

test_pytestmultihost/test_localhost.py

file modified

		`@@ -224,3 +224,11 @@`
		`host = multihost_badpassword.host`
		`with pytest.raises((AuthenticationException, RuntimeError)):`
		`echo = host.run_command(['echo', 'hello', 'world'])`
		`+`
		`+ def test_background(self, multihost):`
		`+ host = multihost.host`
		`+ run_nc = 'nc -l 12080 > /tmp/filename.out'`
		`+ cmd = host.run_command(run_nc, bg=True, raiseonerr=False)`
		`+ send_file = 'nc localhost 12080 < /root/anaconda-ks.cfg'`
		`+ cmd = host.run_command(send_file)`
		`+ assert cmd.returncode == 0`

mrniranjan commented 6 years ago

Signed-off-by: Niranjan M.R mrniranjan@redhat.com

mrniranjan commented 6 years ago

Currently this patch adds support to run command when Transport class is Paramiko .

Test case added:

# py.test -s -v test_localhost.py::TestLocalhost::test_background[paramiko]
==================  test session starts  =======================
platform linux2 -- Python 2.7.11, pytest-2.9.1, py-1.4.31, pluggy-0.3.1 -- /home/mniranja  /python_proj/bin/python
cachedir: ../.cache
ansible: 2.2.1.0
rootdir: /home/mniranja/source/pagure/python-pytest-multihost, inifile:
plugins: modifyjunit-1.0, ansible-2.0.0, multihost-1.1 collected 23 items

test_localhost.py::TestLocalhost::test_background[paramiko] PASSED
================== 1 passed in 0.54 seconds =======================

spoore commented on line 29 of pytest_multihost/host.py 6 years ago

Can we simplify this? Maybe:

if not bg:
    command.wait(raiseonerr=raiseonerr)
return command

Edited 6 years ago by spoore

rebased onto 34529cd

6 years ago

mrniranjan commented 6 years ago

Thanks spoore, added updated patch.

mrniranjan commented 6 years ago

Some more comments about this option. when a command is run with bg=True, there will be no stderr, stdout or returncode . And it's up the user to make sure that the command being run in background is killed in the test case.

We in sssd qe team need this as we would like to run tcpdump and capture packets over ldap to verify certain things. Grepping of logs have never been reliable.

Example:

tcpdump_cmd = 'tcpdump -s0 -w %s port 389' % pcapfile
multihost.master[0].run_command(tcpdump_cmd, bg=True)
pid_cmd = 'pidof tcpdump'
cmd = multihost.master[0].run_command(pid_cmd, raiseonerr=False)
kill_cmd = 'kill -9 %s' % cmd.stdout_text
multihost.master[0].run_command(kill_cmd)
multihost.master[0].transport.get_file(pcapfile, pcapfile)

if the command run in background is not killed , pytest would hang

Edited 6 years ago by mrniranjan