[Kimchi-devel] [PATCH V4] [Wok] Make run_command log its output into a file.

[Ramon Medeiros]

open() can return IOError. Please, add a try when opening it.

https://docs.python.org/2/library/functions.html#open

On 12/24/2015 12:50 PM, pvital at linux.vnet.ibm.com wrote:
> From: Paulo Vital <pvital at linux.vnet.ibm.com>
>
> Adds the ability of run_command to log the output of a console command into a
> given file, like the "tee" command does.
>
> Using this patch, a command that takes too many time to execute can be monitored
> by reading the log file while other tasks are executed.
>
> Signed-off-by: Paulo Vital <pvital at linux.vnet.ibm.com>
> ---
>   src/wok/utils.py | 45 +++++++++++++++++++++++++++++++++++++++++++--
>   1 file changed, 43 insertions(+), 2 deletions(-)
>
> diff --git a/src/wok/utils.py b/src/wok/utils.py
> index 7b1b309..9b0a113 100644
> --- a/src/wok/utils.py
> +++ b/src/wok/utils.py
> @@ -28,6 +28,7 @@ import pwd
>   import re
>   import sqlite3
>   import subprocess
> +import sys
>   import traceback
>   import xml.etree.ElementTree as ET
>   from cherrypy.lib.reprconf import Parser
> @@ -135,13 +136,15 @@ def import_module(module_name, class_name=''):
>       return __import__(module_name, globals(), locals(), [class_name])
>
>
> -def run_command(cmd, timeout=None, silent=False):
> +def run_command(cmd, timeout=None, silent=False, tee=None):
>       """
>       cmd is a sequence of command arguments.
>       timeout is a float number in seconds.
>       timeout default value is None, means command run without timeout.
>       silent is bool, it will log errors using debug handler not error.
>       silent default value is False.
> +    tee is a file path to store the output of the command, like 'tee' command.
> +    tee default value is None, means output will not be logged.
>       """
>       # subprocess.kill() can leave descendants running
>       # and halting the execution. Using psutil to
> @@ -159,6 +162,19 @@ def run_command(cmd, timeout=None, silent=False):
>           else:
>               timeout_flag[0] = True
>
> +    # function to append the given msg into the log_file
> +    def tee_log(msg=None, log_file=None):
> +        if (msg is None) or (log_file is None):
> +            return
> +
> +        f = open(log_file, 'a')
> +        msg += '\n'
> +        try:
> +            f.write(msg)
> +        except TypeError:
> +            f.write(msg.encode('utf_8'))
> +        f.close()
> +
>       proc = None
>       timer = None
>       timeout_flag = [False]
> @@ -171,8 +187,33 @@ def run_command(cmd, timeout=None, silent=False):
>               timer.setDaemon(True)
>               timer.start()
>
> -        out, error = proc.communicate()
>           wok_log.debug("Run command: '%s'", " ".join(cmd))
> +        if tee is not None:
> +            if os.path.exists(tee):
> +                os.remove(tee)
> +            output = []
> +            while True:
> +                line = ""
> +                try:
> +                    line = proc.stdout.readline()
> +                    line = line.decode('utf_8')
> +                except Exception:
> +                    type, e, tb = sys.exc_info()
> +                    wok_log.error(e)
> +                    wok_log.error("The output of the command could not be "
> +                                  "decoded as %s\ncmd: %s\n line ignored: %s" %
> +                                  ('utf_8', cmd, repr(line)))
> +                    pass
> +
> +                output.append(line)
> +                if not line:
> +                    break
> +                line = line.rstrip('\n\r')
> +                tee_log(line, tee)
> +            out = ''.join(output)
> +            error = proc.stderr.read()
> +        else:
> +            out, error = proc.communicate()
>
>           if out:
>               wok_log.debug("out:\n%s", out)
> --
> 2.5.0
>
> _______________________________________________
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> Kimchi-devel at ovirt.org
> http://lists.ovirt.org/mailman/listinfo/kimchi-devel
>

-- 

Ramon Nunes Medeiros
Kimchi Developer
Linux Technology Center Brazil
IBM Systems & Technology Group
Phone : +55 19 2132 7878
ramonn at br.ibm.com