Check multiple file parms in single os.access?

James McMahon jsmcmahon3 at gmail.com
Thu Apr 13 07:31:02 EDT 2017


Hello. Am a Python newbie. I have researched and found examples how we can
check existence, readability, and write-ability on a given fully-qualified
filename for the current python script user. Evidently os.access is the way
to go, wrapped in some additional try and catch logic that helps insulate
us from changes in file state after our os.access checks.

I understand that os.stat() calls can be relatively expensive. I assume
likewise for os.access(). Since I'm going to apply my Python permission
check script within a NiFi ExecuteScript processor handling many flowfiles,
I seek any and all performance optimizations I possibly can.

Is there a way to mask the F_OK, R_OK, and W_OK in a single os.access
call? I'm guessing there must be, rather than doing this

if ( os.access(fqfname,os.F_OK) and os.access(fqfname,os.R_OK) and
os.access(fqfname,os.W_OK)) :

Thanks in advance for your insights. -Jim


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