Okay. I have completed my first python program.It has around 1000 lines of code.
During development I placed plenty of print
statements before running a command
Putting your own file-like in sys.stdout
will let you capture the text output via print
.
Just a note about append vs write mode. Change filemode to "w" if you would like it to replace log file. I also had to comment out the stream. Then using logging.info() was outputting to file specified.
if __name__ == '__main__':
LOG_FORMAT = '%(asctime)s:%(levelname)s ==> %(message)s'
logging.basicConfig(
level=logging.INFO,
filename="logfile",
filemode="w",
format=LOG_FORMAT
#stream=sys.stdout
)
A simple way to redirect stdout and stderr using the logging module is here: How do I duplicate sys.stdout to a log file in python?
Next time, you'll be happier if instead of using print
statements at all you use the logging
module from the start. It provides the control you want and you can have it write to stdout while that's still where you want it.
Many people here have suggested redirecting stdout. This is an ugly solution. It mutates a global and—what's worse—it mutates it for this one module's use. I would sooner make a regex that changes all print foo
to print >>my_file, foo
and set my_file
to either stdout or an actual file of my choosing.
sys.stdout
for the process.os.system
is virtually always inferior to using the subprocess
module. The latter needn't invoke the shell, doesn't pass signals in a way that usually is unwanted, and can be used in a non-blocking manner.
You can create a log file and prepare it for writing. Then create a function:
def write_log(*args):
line = ' '.join([str(a) for a in args])
log_file.write(line+'\n')
print(line)
and then replace your print() function name with write_log()
Python lets you capture and assign sys.stdout - as mentioned - to do this:
import sys
old_stdout = sys.stdout
log_file = open("message.log","w")
sys.stdout = log_file
print "this will be written to message.log"
sys.stdout = old_stdout
log_file.close()