[Kimchi-devel] [PATCH V2] add a synchronous function with timeout to execute command

[Sheldon]

How to test this patch:

1. run a command with long time.*
**$ sudo python -c 'import sys;**
**sys.path.insert(0, "src");**
**from kimchi import utils;**
**print utils.run_command([**"dd", "if=/dev/zero", "of=/dev/null"]**, 1.5)'*

subprocess is killed by signal.SIGKILL for timeout 1.5 seconds
('', '', -9, True)

2. run a command failed
*$ sudo python -c 'import sys;**
**sys.path.insert(0, "src");**
**from kimchi import utils;**
**print utils.run_command(["not-command"])'*

Failed to run command: not-command.
   [Errno 2] No such file or directory
(None, None, None, False)


3. run a command with an error optional param
*$ sudo python -c 'import sys;**
**sys.path.insert(0, "src");**
**from kimchi import utils;**
**print utils.run_command(["ls", "-w"])'*

('', "ls: option requires an argument -- 'w'\nTry 'ls --help' for more 
information.\n", 2, False)

4. run a command successfully
*$ sudo python -c 'import sys;**
**sys.path.insert(0, "src");**
**from kimchi import utils;**
**print utils.run_command(["echo", "test"])'*

('test\n', '', 0, False)


On 01/10/2014 10:10 PM, shaohef at linux.vnet.ibm.com wrote:
> From: ShaoHe Feng <shaohef at linux.vnet.ibm.com>
>
> We need a common function to execute shell command.
> We also need timeout when execute shell command.
>
> A threading.Timer is used to send signal.SIGKILL to kill the command
> when timeout.
>
> Signed-off-by: Royce Lv <lvroyce at linux.vnet.ibm.com>
> Signed-off-by: ShaoHe Feng <shaohef at linux.vnet.ibm.com>
> ---
>   src/kimchi/utils.py | 43 +++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 43 insertions(+)
>
> diff --git a/src/kimchi/utils.py b/src/kimchi/utils.py
> index af245c6..c7165ce 100644
> --- a/src/kimchi/utils.py
> +++ b/src/kimchi/utils.py
> @@ -23,6 +23,7 @@
>
>   import cherrypy
>   import os
> +import subprocess
>   import urllib2
>
>
> @@ -30,6 +31,7 @@ from cherrypy.lib.reprconf import Parser
>
>
>   from kimchi import config
> +from threading import Timer
>
>
>   kimchi_log = cherrypy.log.error_log
> @@ -96,3 +98,44 @@ def check_url_path(path):
>           return False
>
>       return True
> +
> +
> +def run_command(cmd, timeout=None):
> +    def kill_proc(proc, timeout_flag):
> +        timeout_flag[0] = True
> +        proc.kill()
> +
> +    proc = None
> +    timer = None
> +    timeout_flag = [False]
> +
> +    try:
> +        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
> +                                stderr=subprocess.PIPE)
> +        if timeout is not None:
> +            timer = Timer(timeout, kill_proc, [proc, timeout_flag])
> +            timer.start()
> +
> +        out, error = proc.communicate()
> +        kimchi_log.debug("Run command: '%s'", " ".join(cmd))
> +
> +        if out or error:
> +            kimchi_log.debug("out:\n %s\nerror:\n %s", out, error)
> +
> +        if proc.returncode == -9 and timeout_flag[0] is True:
> +            kimchi_log.error("subprocess is killed by signal.SIGKILL "
> +                             "for timeout %s seconds", timeout)
> +
> +        return out, error, proc.returncode, timeout_flag[0]
> +    except Exception as e:
> +        msg = "Failed to run command: %s." % " ".join(cmd)
> +        msg = msg if proc is None else msg + "\n  error code: %s."
> +        kimchi_log.error("%s\n  %s", msg, e)
> +
> +        if proc:
> +            return out, error, proc.returncode, timeout_flag[0]
> +        else:
> +            return None, None, None, timeout_flag[0]
> +    finally:
> +        if timer and not timeout_flag[0]:
> +            timer.cancel()


-- 
Thanks and best regards!

Sheldon Feng(冯少合)<shaohef at linux.vnet.ibm.com>
IBM Linux Technology Center

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