Application Design Issue

perlCrazy has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Application Design Issue by apl (Monsignor) on Feb 04, 2008 at 12:36 UTC
Similarly, you could have a single file that contained the last successfully processed step. When the process restarts, read the one file and process accordingly (i.e. the value is '3', now process Step 4).	[reply]
Re: Application Design Issue by stiller (Friar) on Feb 04, 2008 at 11:32 UTC
You need an easy way to keep score, I have used a system where I `mv step_1_started step_1_done` and `mv step_1_done step_2_started` ... `unlink step_8_done` Now you can `if (-e step_1_done)` [download]	[reply] [d/l] [select]
Re^2: Application Design Issue by perlCrazy (Monk) on Feb 04, 2008 at 11:49 UTC
I am creating step1_file that indicates that step1 has been executed successfully. If any error comes then that step${n}_file will not be created. How this to implement in main script. Are you indicating something like, create label and then use GO TO ?	[reply]
Re^3: Application Design Issue by stiller (Friar) on Feb 04, 2008 at 12:09 UTC
I would read in (with glob) the step_X_done file. Read its number, or 1 into a variable `$already_done` `for my $todo ($already_done .. $final_step){ do_step1() if $todo == 1; do_step2() if (-e step_1_done);` [download] then wrap the code for each step in separate subs. Now you can manually delete a "step-file" to have the job start from scratch, or at some spesific step, if you ever need that.	[reply] [d/l] [select]
Re: Application Design Issue by TedPride (Priest) on Feb 04, 2008 at 13:55 UTC
Create a new module with a die wrapper, that stores the last place the user was at. It doesn't matter what the mechanism is - you can add / remove file markers, or you can store the position in a database (I recommend this for sure if you may run more than one user simultaneously) - but the wrapper will allow you to exit from any point with the desired action and only have to give a simple function call `myDie($user, $position, $error)` Then of course you'll have another function that you run at the start that picks up the last user position, which is then used with conditionals to skip the parts you already covered. `myPosition($user)` Again, the mechanism isn't important, you can swap it around later if you feel like it.	[reply] [d/l] [select]
Re: Application Design Issue by jdporter (Paladin) on Feb 04, 2008 at 16:24 UTC
Wouldn't you normally want to resume processing from the failed step (i.e. step 3)? I would think the objective would be for every step to have been executed successfully. No? A word spoken in Mind will reach its own level, in the objective world, by its own weight	[reply]
Re: Application Design Issue by plobsing (Friar) on Feb 04, 2008 at 23:34 UTC
Sounds like a job for `dump` and `undump`. If only I could get them to work.	[reply] [d/l] [select]


Perl Monk, Perl Meditation
	PerlMonks