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From: Paul M. <pau...@gm...> - 2022-03-22 20:18:53
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If you are just trying to, determine if there was an error thrown by the module command,
Just test the exit status:
EXIT STATUS
The module command exits with 0 if its execution succeed. Otherwise 1
is returned.
Keep in mind that every call to the module command redirects sys.stdout so that the output is evaluated by python (so you probably can't capture that).
And sys.stderr redirection by a module command might depend on what stderr is connected to.
Last - stderr and stdout are buffered IO, so you may also have to do a flush before reading them.
I should preface the below with, "I haven't coded in python":
Maybe you need to test your code with no modules involved first.
You might want to read this (seems like stringIO() may have some limitations).
https://stackoverflow.com/questions/1218933/can-i-redirect-the-stdout-into-some-sort-of-string-buffer
On 2022-03-22 09:18 AM, Jonathan Buck wrote:
> Hi Jacques,
>
> Thanks for the quick reply! I have successfully use the module() command
> to setup environments without issue. What I'm hoping to do is capture any
> stderr messages to a variable. I have several use cases for this, most
> importantly I'm attempting to automate checks against our hundreds of
> modules to determine if any of them are broken when loaded. I'm unable to
> redirect stdout/stderr in a manner that I've used before which I believe is
> due to the command being a subprocess. I'm not a python guru, but the
> popen statement declares " stdout=subprocess.PIPE" which I thought was the
> right way to get the stdout returned to the originating process.
>
> All that being said, here's my test script:
>
> import os
> import sys
> from io import StringIO
>
> # Setup variables to hold stdout/stderr
> result_stdout = StringIO()
> result_stderr = StringIO()
> sys.stdout = result_stdout
> sys.stderr = result_stderr
>
> # setup environment module
> exec(open('/p/app/Modules/4.7.1/init/python.py').read())
>
> # run
> print("----- TRY RUNNING MODULE COMMAND -----")
> module('--version')
> print("----- DONE RUNNING MODULE COMMAND -----")
> module_stdout = result_stdout.getvalue()
> module_stderr = result_stderr.getvalue()
>
> # reset stdout/stderr to defaults
> sys.stdout = sys.__stdout__
> sys.stderr = sys.__stderr__
>
> # print out what was captured to the variables
> print("===== TRY PRINTING STDOUT =====")
> sys.stdout.write(module_stdout)
> print("===== DONE PRINTING STDOUT =====")
>
> print("***** TRY PRINTING STDERR *****")
> sys.stderr.write(module_stderr)
> print("***** DONE PRINTING STDERR *****")
>
>
> As you can see, it's simple. I make sure to reset stdout/stderr to
> defaults, however these are my results:
>
> ~> python3 module_test.py
> Modules Release 4.7.1 (2021-04-06)
> ===== TRY PRINTING JSON STDOUT =====
> ----- TRY RUNNING MODULE COMMAND -----
> ----- DONE RUNNING MODULE COMMAND -----
> ===== DONE PRINTING JSON STDOUT =====
> ***** TRY PRINTING JSON STDERR *****
> ***** DONE PRINTING JSON STDERR *****
> ~>
>
> This shows that my stdout redirect is capturing the 'print' statements
> for running the module command. However the output for the module
> command prints at the very beginning and doesn't show up. Any
> thoughts? I found a fancy way to do the same thing in bash, and I
> proved that in bash the same output is going to stdout.
>
>
> Very Respectfully,
>
> Jonathan
>
>
> On Tue, Mar 22, 2022 at 8:06 AM Contact <dv...@cr...> wrote:
>
>> Hello,
>>
>> In my case I used modules from python with the following logic:
>>
>> import os
>> exec(open(/home/jrp/modules/init/python.py')).read())
>> module('avail')
>> module('load', 'gcc/7')
>> module('list')
>>
>> From the above example,
>>
>> - exec call will allow me to use modules from python itself and define
>> module function
>> - Each module function invocation will be redirected to module to
>> perform required action
>>
>> As reminder, the content of stdout is used by modules to setup all
>> required environment functions, functions/alias (if supported by current
>> shell), ...
>>
>> I hope it will help you.
>>
>> Jacques
>>
>>
>> Le 21/03/2022 à 20:09, Jonathan Buck a écrit :
>>
>> Hi,
>>
>> I'm attempting to capture and act on the stdout and stderr of the module
>> command. The python implementation appears to be a subprocess for which I
>> wasn't able to redirect with io.StringIO() as I have with other output
>> capture.
>>
>> I attempted to look through the code, which I admit I don't fully
>> understand and appears to have a one-liner style of executing the
>> subprocess. I'm writing code that integrates with a production system, so
>> I'm not able to modify the python.py code.
>>
>> Does anyone know how else this might be accomplished? Or should I make
>> this a feature request?
>>
>> Thanks for your help,
>> Jonathan
>>
>>
>> _______________________________________________
>> Modules-interest mailing lis...@li...https://lists.sourceforge.net/lists/listinfo/modules-interest
>>
>>
>
>
>
> _______________________________________________
> Modules-interest mailing list
> Mod...@li...
> https://lists.sourceforge.net/lists/listinfo/modules-interest
>
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