A snippet from a blog post about writing extensions - how to write a logger.

learning-extensions-2

import datetime

log_file            = op( 'text_log_file' )
log_path            = "example_extensions/log_files/log.txt"

full_text           = '''{now}

Current Year        | {year}
Current Month       | {month}
Current Day         | {day}
Current Hour        | {hour}
Current Minute      | {minute}
Current Second      | {second}
Current Microsecond | {microsecond}
'''

raw_date_time       = "On {month}-{day}-{year} at {hour}:{minute}:{second}"

verbose_log_message = '''============================
VERBOSE MESSAGE

{date_time}
----------------------------
operator            || {operator}
At Network Location || {path}

----------------------------
Logged
{message}
============================
'''

log_message         = '''----------------------------
{now}
----------------------------
{operator}
{path}
{message}
'''

class Ext_example():

    def __init__( self ):
        '''The init function.

        We're not doing anything with our init function in this example
        so we'll leave this empty.

        Notes
        ---------------
        ''' 
        return

    def Log_date( self ):
        year                        = datetime.datetime.now().year
        month                       = datetime.datetime.now().month
        day                         = datetime.datetime.now().day
        hour                        = datetime.datetime.now().hour
        minute                      = datetime.datetime.now().minute
        second                      = datetime.datetime.now().second

        updated_log_date            = log_date.format( 
                                                        month       = month,
                                                        day         = day,
                                                        year        = year,
                                                        hours       = hour,
                                                        minutes     = minute,
                                                        seconds     = second
                                                    )

        return updated_log_date

    def Log_date_time( self ):
        '''Create a formatted time stamp

        A look at how we might create a formatted time stamp to use with
        various logging applications.

        Arguments
        --------------- 
        None

        Returns
        ---------------
        formatted_text( str ) - a string time stamp

        Notes
        ---------------
        '''

        now         = datetime.datetime.now()
        year        = datetime.datetime.now().year
        month       = datetime.datetime.now().month
        day         = datetime.datetime.now().day
        hour        = datetime.datetime.now().hour
        minute      = datetime.datetime.now().minute
        second      = datetime.datetime.now().second
        microsecond = datetime.datetime.now().microsecond

        date_time   = raw_date_time.format( 
                                        month   = month,
                                        day     = day,
                                        year    = year,
                                        hour    = hour,
                                        minute  = minute,
                                        second  = second
                                        )

        return date_time

    def Log_message( self, operator, message, verbose=False, text_port_print=True, append_log=True ):
        '''Logging Method.

        A simple look at how you might start to think about building a logger for a TouchDesigner
        application. A logger is a great way to build out files with time stamped events. The
        more complex a project becomes, the more important it can become to have some means
        of logging the operations of your program. Here's a simple look at what that might
        look like.

        Arguments
        --------------- 
        operator( touch object ) - the touch object whose path you'd like incldued in the log message
        message( str ) - a message to include in the log
        verbose( bool ) - a toggle for verbose or compact messages
        text_port_print( bool ) - a toggle to print to the text port, or not
        append_log( bool ) - a toggle to append to the log file , or not

        Example
        --------------- 
        target_op       = op( 'constant1' )
        message         = "This operator needs attention"

        parent().Log_message( target_op, message )

        also

        parent().Log_message( target_op, message, verbose = True )

        Returns
        ---------------
        None

        Notes
        ---------------
        You'll notice that some arguments receive default values. This is so you don't have
        to include them in the call. This means that by default the message will be compact, 
        will print to the text port, and will append the log file.
        '''

        path        = operator.path
        op_name     = operator.name

        # logic tests for verbose or compact
        if verbose:
            message = verbose_log_message.format(
                                                    date_time   = self.Log_date_time(),
                                                    operator    = op_name,
                                                    path        = path,
                                                    message     = message
                                                )

        else:
            message = log_message.format(
                                            now                 = self.Log_date_time(),
                                            operator            = op_name,
                                            path                = path,
                                            message             = message
                                        )

        # logic tests for text_port_print
        if text_port_print:
            print( message )

        else:
            pass

        # log tests for appending log
        if append_log:
            log_file.write( '\n' + message )

        else:
            pass

        # save the log file to disk - external from the TouchDesigner project   
        self.Save_log()

        return

    def Save_log( self ):
        '''Saves log to disk.

        This helper function saves the log file to disk.

        Notes
        ---------------
        None
        '''

        op( log_file ).save( log_path )

        return

    def Clear_log( self ):
        '''Clears Log File.

        This helper function clears the text dat used to hold the log file.

        Notes
        ---------------
        None
        '''

        op( log_file ).clear()

        return