Logger

All the log messages should be printed with the methods available in fsmBase. This ensures that they are threaded in a coherent way. In the loader a verbosity level can be specified, so that only the messages with verbosity level lower or equal to that are printed. For example a verbosity of zero is related to ERROR logging, and messages are always printed, while a higher verbosity may be useful only while debugging.

There are three options to log:

Log to Standard Output

This is the easiest method, and the default one if no other is specified. Should be used only while developing or on small tests. All the messages are written to the standard output of the console where the executable is launched.

This is achieved via a base class called fsmLogger.

class fsmLogger([level=3])

Collect all the log messages from the various FSMs loaded and print them to stdout.

This can be used by creating an instance and passing it as an optional argument to all the FSMs, or (better) using the loader with no option specified. The verbosity can be set with setVerbosity() function.

Log to File

A better approach is to write logs to file, in order to open them only when needed. For this reason a derivate class of the previous one has been developed:

class fsmFileLogger([level=3[, directory="logs/"[, prefix=""]]])
Parameters:

  • level (int) – the log level

  • directory (string) – the folder where all the log files will be written

  • prefix (string) – a common prefix for all the logs of this executable

This will write one file for each instance of FSM loaded in the executable, and will use the prefix, plus the name of the FSM to name the file.

It can be used directly by creating an instance and passing it as an optional argument to all the FSMs, or (better) using the loader and its logToFile() function. The verbosity can be set with setVerbosity() function.

Log to Syslog

Planned

Examples

Choosing the logging method:

from smblib import loader

l = loader()
l.setVerbosity(2) # INFO verbosity
l.logToFile("~/fsmlogs/", "exampleDaemon") # comment this line to log to stdout

l.load( ... ) # load your FSMs

l.start()

Using log functions inside the FSM code:

def mymethod_eval(self):
    self.logE("This is an ERROR level log message!")
    self.logW("This is an WARNING level log message!")
    self.logI("This is an INFO level log message!")
    self.logD("This is an DEBUG level log message!")