Re: Using logging module to log into flash drive
On Jun 9, 7:57 pm, Carl Banks pavlovevide...@gmail.com wrote: On Jun 9, 8:57 am, kretel krzysztof.re...@googlemail.com wrote: Hi All, I am trying to implement the following functionality: 1. log messages to the flash drive 2. if the flash drive is not available, switch handler to the BufferringHandler and log into buffer, 3. once the flash drive is plugged in and available store the logs from BufferHandler into that flash drive and switch the handler into RotateFileHandler. Which approach would you suggest to use while implementing this functionality? One that come into my mind is to have one process or thread to check periodically if the flashdrive is available, and have a flag that will indicate that we can store the logs into the flash drive. But I don't particularly like this approach. Would you do it different way? Any suggestions are appreciated. I'd refactor the steps this way: 1. log messages to a buffer 2. periodically flush the buffer to the flash drive, if it's available The periodically part could be accomplished with a thread or scheduled delays, however suits your application. It might not be a final if you need to log messages promptly, but that's how I'd begin. Carl Banks Hi Carl, Thanks for the advice. I haven't think about it this way, but it looks like that might be the starting point. Thanks, Krzysztof -- http://mail.python.org/mailman/listinfo/python-list
Re: Using logging module to log into flash drive
On Tue, 9 Jun 2009 18:10:18 +0100, A. Cavallo a.cava...@mailsnare.com wrote: [top-posting fixed] On Tuesday 09 June 2009 16:57:00 kretel wrote: Hi All, I am trying to implement the following functionality: 1. log messages to the flash drive 2. if the flash drive is not available, switch handler to the BufferringHandler and log into buffer, 3. once the flash drive is plugged in and available store the logs from BufferHandler into that flash drive and switch the handler into RotateFileHandler. Which approach would you suggest to use while implementing this functionality? First, to ignore the words flash drive and think in terms of can I open the file named so-and-so for writing?. Unless you absolutely must avoid storing your file on a file system based on some other storage technology. One that come into my mind is to have one process or thread to check periodically if the flashdrive is available, and have a flag that will indicate that we can store the logs into the flash drive. But I don't particularly like this approach. Would you do it different way? Any suggestions are appreciated. Hi, the problem screams for a separate thread. I don't hear any screaming. It seems simpler to just def log(something): if logging_to_memore() and seconds_since_i_last_checked() N: try_to_switch_to_file() do_the_actual_logging(something) unless it's vital that as many of these logs as possible survive a crash (in which case I guess the program would also refuse to exit until the user finds the physical flash memory device somewhere and mounts it correctly -- flashback to ancient floppy-based Macs). Yes, I find the requirements quite odd. /Jorgen -- // Jorgen Grahn grahn@Ph'nglui mglw'nafh Cthulhu \X/ snipabacken.se R'lyeh wgah'nagl fhtagn! -- http://mail.python.org/mailman/listinfo/python-list
Using logging module to log into flash drive
Hi All, I am trying to implement the following functionality: 1. log messages to the flash drive 2. if the flash drive is not available, switch handler to the BufferringHandler and log into buffer, 3. once the flash drive is plugged in and available store the logs from BufferHandler into that flash drive and switch the handler into RotateFileHandler. Which approach would you suggest to use while implementing this functionality? One that come into my mind is to have one process or thread to check periodically if the flashdrive is available, and have a flag that will indicate that we can store the logs into the flash drive. But I don't particularly like this approach. Would you do it different way? Any suggestions are appreciated. Cheers, Krzysztof -- http://mail.python.org/mailman/listinfo/python-list
Re: Using logging module to log into flash drive
Hi, the problem screams for a separate thread. Anyway there's a TimedRotatingFileHandler handler in the logging package: you can derive from it and change the emit/doRollover pair to hold the records until a device is not ready. Regards, Antonio On Tuesday 09 June 2009 16:57:00 kretel wrote: Hi All, I am trying to implement the following functionality: 1. log messages to the flash drive 2. if the flash drive is not available, switch handler to the BufferringHandler and log into buffer, 3. once the flash drive is plugged in and available store the logs from BufferHandler into that flash drive and switch the handler into RotateFileHandler. Which approach would you suggest to use while implementing this functionality? One that come into my mind is to have one process or thread to check periodically if the flashdrive is available, and have a flag that will indicate that we can store the logs into the flash drive. But I don't particularly like this approach. Would you do it different way? Any suggestions are appreciated. Cheers, Krzysztof -- http://mail.python.org/mailman/listinfo/python-list
Re: Using logging module to log into flash drive
On Jun 9, 6:10 pm, A. Cavallo a.cava...@mailsnare.com wrote: Hi, the problem screams for a separate thread. I was thinking about that, as mentioned in the first post. Although, I was wonder if there is another way to tackle the problem. Anyway there's a TimedRotatingFileHandler handler in the logging package: you can derive from it and change the emit/doRollover pair to hold the records until a device is not ready. Hm, that might be the way to go. Will have a try. If anyone has other thoughts, please share them. Thanks, Krzysztof -- http://mail.python.org/mailman/listinfo/python-list
Re: Using logging module to log into flash drive
Anyway there's a TimedRotatingFileHandler handler in the logging package: you can derive from it and change the emit/doRollover pair to hold the records until a device is not ready. Hm, that might be the way to go. Will have a try. I had another look at the logging package. The class TimedRotatingFileHandler within the initialisation method uses the FileHandler.__init__. Whereas the FileHandler.__init__ method opens the stream in the 'append' mode (mode='a'). If the flash drive is not available while you start the script, which equals that you can't open a file in the append mode, then the TimedRotatingFileHandler (or FileHandler) fails. In my opinion the only way to go through this is to use two different handlers and once the flash drive is available then start to use the FileHandler. Still not sure if I want to use separate thread for checking the flash drive availability. Probably I need to build it this way. Regards Krzysztof -- http://mail.python.org/mailman/listinfo/python-list
Re: Using logging module to log into flash drive
On Jun 9, 8:57 am, kretel krzysztof.re...@googlemail.com wrote: Hi All, I am trying to implement the following functionality: 1. log messages to the flash drive 2. if the flash drive is not available, switch handler to the BufferringHandler and log into buffer, 3. once the flash drive is plugged in and available store the logs from BufferHandler into that flash drive and switch the handler into RotateFileHandler. Which approach would you suggest to use while implementing this functionality? One that come into my mind is to have one process or thread to check periodically if the flashdrive is available, and have a flag that will indicate that we can store the logs into the flash drive. But I don't particularly like this approach. Would you do it different way? Any suggestions are appreciated. I'd refactor the steps this way: 1. log messages to a buffer 2. periodically flush the buffer to the flash drive, if it's available The periodically part could be accomplished with a thread or scheduled delays, however suits your application. It might not be a final if you need to log messages promptly, but that's how I'd begin. Carl Banks -- http://mail.python.org/mailman/listinfo/python-list
