redirecting stdout to a file as well as screen

[SamG]

How could i make, from inside the program, to have the stdout and
stderr to be printed both to a file as well the terminal(as usual).

 

[Ant]

How could i make, from inside the program, to have the stdout and
stderr to be printed both to a file as well the terminal(as usual).

One way would be to create a custom class which has the same methods
as the file type, and held a list of file-like objects to write to.
e.g.

class multicaster(object):
def __init__(self, filelist):
self.filelist = filelist

def write(self, str):
for f in self.filelist:
f.write(str)
def writelines(self, str_list):
#etc

Then assign stdout and stderr to a new instance of one of these
objects:

mc = multicaster([sys.stdout, sys.stderr, log_file])
sys.stdout = mc
sys.stderr = mc

HTH

 

[Gabriel Genellina]

How could i make, from inside the program, to have the stdout and
stderr to be printed both to a file as well the terminal(as usual).

A very minimal example:

import sys

class Tee(file):
others = ()

def write(self, data):
file.write(self, data)
for f in others:
f.write(data)

tee = Tee(r"c:\temp\output.log","wt")
tee.others = [sys.stdout, sys.stderr]
sys.stdout = sys.stderr = tee

print dir(sys)
sys.foo # error

 

[SamG]

How could i make, from inside the program, to have the stdout and
stderr to be printed both to a file as well the terminal(as usual).

A very minimal example:

import sys

class Tee(file):
others = ()

def write(self, data):
file.write(self, data)
for f in others:
f.write(data)

tee = Tee(r"c:\temp\output.log","wt")
tee.others = [sys.stdout, sys.stderr]
sys.stdout = sys.stderr = tee

print dir(sys)
sys.foo # error

This is only creating an out.log file and all the stdout and stderr
are logged there.

 

[SamG]

How could i make, from inside the program, to have the stdout and
stderr to be printed both to a file as well the terminal(as usual).

One way would be to create a custom class which has the same methods
as the file type, and held a list of file-like objects to write to.
e.g.

class multicaster(object):
def __init__(self, filelist):
self.filelist = filelist

def write(self, str):
for f in self.filelist:
f.write(str)
def writelines(self, str_list):
#etc

Then assign stdout and stderr to a new instance of one of these
objects:

mc = multicaster([sys.stdout, sys.stderr, log_file])
sys.stdout = mc
sys.stderr = mc

HTH

I have written this....

import sys

class multicaster(object):
def __init__(self, filelist):
self.filelist = filelist

def write(self, str):
for f in self.filelist:
f.write(str)

log_file='out.log'
mc = multicaster([sys.stdout, sys.stderr, log_file])
sys.stdout = mc
sys.stderr = mc

print "Hello"

And i get this when i run the porgram.

HelloHelloTraceback (most recent call last):
Traceback (most recent call last):

Kindly advice!

 

[7stud]

One way would be to create a custom class which has the same methods
as the file type, and held a list of file-like objects to write to.
e.g.

class multicaster(object):
def __init__(self, filelist):
self.filelist = filelist

def write(self, str):
for f in self.filelist:
f.write(str)
def writelines(self, str_list):
#etc

Then assign stdout and stderr to a new instance of one of these
objects:

mc = multicaster([sys.stdout, sys.stderr, log_file])
sys.stdout = mc
sys.stderr = mc

HTH

I have written this....

import sys

class multicaster(object):
def __init__(self, filelist):
self.filelist = filelist

def write(self, str):
for f in self.filelist:
f.write(str)

log_file='out.log'
mc = multicaster([sys.stdout, sys.stderr, log_file])
sys.stdout = mc
sys.stderr = mc

print "Hello"

And i get this when i run the porgram.

HelloHelloTraceback (most recent call last):
Traceback (most recent call last):

Kindly advice!

Try:

log_file = open("out.log", "w")

 

[Antoon Pardon]

How could i make, from inside the program, to have the stdout and
stderr to be printed both to a file as well the terminal(as usual).

One way would be to create a custom class which has the same methods
as the file type, and held a list of file-like objects to write to.
e.g.

class multicaster(object):
def __init__(self, filelist):
self.filelist = filelist

def write(self, str):
for f in self.filelist:
f.write(str)
def writelines(self, str_list):
#etc

Then assign stdout and stderr to a new instance of one of these
objects:

mc = multicaster([sys.stdout, sys.stderr, log_file])
sys.stdout = mc
sys.stderr = mc

HTH

I have written this....

import sys

class multicaster(object):
def __init__(self, filelist):
self.filelist = filelist

def write(self, str):
for f in self.filelist:
f.write(str)

log_file='out.log'

log_file is not a file but a string, So when you reach the
write method in your multicaster you get an atttribute error
because a string has no write method

mc = multicaster([sys.stdout, sys.stderr, log_file])

Since sys.stdout and sys.stderr usually both refer to
the terminal, this will result in your output appearing
twice on the terminal

sys.stdout = mc
sys.stderr = mc

Maybe you are better of leaving sys.stderr as it is,
at least until you are sure your multicaster itself
is working as it should.

 

[Gabriel Genellina]

This is only creating an out.log file and all the stdout and stderr
are logged there.

Sorry, `for f in others:` should read `for f in self.others:`

 

[SamG]

En Thu, 12 Apr 2007 06:01:18 -0300, SamG <[email protected]> escribió:





Sorry, `for f in others:` should read `for f in self.others:`

Does not make difference, does this work for you? Im working on linux.
But this code looks portable except for the file path

 

[Gabriel Genellina]

Does not make difference, does this work for you? Im working on linux.
But this code looks portable except for the file path

Yes. And it's rather similar to your other example... Omit sys.stderr as
Antoon Pardon suggested.

 

[SamG]

En Thu, 12 Apr 2007 07:23:43 -0300, SamG <[email protected]> escribió:





Yes. And it's rather similar to your other example... Omit sys.stderr as
Antoon Pardon suggested.

Thanks people i have got it working now...

with this program!

#END
import sys

class multicaster(object):
def __init__(self, filelist):
self.filelist = filelist

def write(self, str):
for f in self.filelist:
f.write(str)

log_file=open('out.log','w')
mc = multicaster([sys.stderr, log_file])
sys.stdout = mc
sys.stderr = mc
sys.stdout.write( "Mojozoox\n")
sys.stderr.write( "Hello\n")
#END

works perfect for my needs.