Existential crisis

Today I configured BIND from scratch and I realize that my knowledge on something as basic as DNS was a little too superficial. I tend to be perfectionist with the things related to my career but I will never master everything I like so I have to pick one of the many things in the list and try to make deep understanding on it.

What should I specialize in? I don’t know yet and I will delay the answer to avoid losing focus. In the meantime, I’ll keep posting and eventually the right answer will show itself, hopefully soon :D.

Date/Time operations

Since I am not very fanatic of software homogeneity, when I write perl scripts and I need some function that performs certain task I use commands from console whenever it’s available even knowing that could be an equivalent Perl module available out there.

When your main goal is to get things done in the least amount of time, you cannot afford the time wasted in searching a library/module when the tools are just as far as calling a external program. This doesn’t mean that your code has to look horrible, it means that there’s no need to search for a (long) piece of code to attach it to yours in order to make your program¬†homogeneous. After all, if you know how to write clean code, you will do it even if you mix 2323423423 languages inside your perl script.

Date/Time arithmetic using Perl.

I am aware of the existence of DateTime.pm but I have no experience using it. This was not the case with date command which finally led me to skip the learning curve and pass directly to the coding job.

The problem.

From a CDR entry containing end-datetime and duration, calculate the start-time, and transform the output using the YYMMDD/HHMMSS format.

[perl]

use strict;
use warnings;

sub main()
{
my $startTime = “02/01/2011 12:02:00”;
my $secs = 3650;

print “$startTime – $secs secs (YYMMDD HHMMSS) = @{ [ CalculateDate(“$startTime”, $secs) ] }”;
print “$secs secs in HHMMSS format is = @{ [ FormatTime($secs) ] } n”;
}

sub CalculateDate($$)
{
my ($date, $secs) = @_;

$date = FormatDateTime(date --date "$date $secs seconds ago");

return $date;
}

sub FormatDateTime($)
{
return date --date "$_[0]" +"%y%m%d %H%M%S";
}

sub FormatTime($)
{
my ($seconds, $hours, $mins, $secs) = shift;

$hours = padLeft(int($seconds / 3600));

$mins = padLeft($hours == 0 ? int($seconds / 60) : int(($seconds – ($hours * 3600)) / 60));

$secs = padLeft($hours == 0 && $mins == 0 ? $seconds : $seconds % 60);

return “$hours$mins$secs”;
}

sub padLeft($)
{
my $value = shift;
return (length “$value” == 1) ? “0$value” : $value;
}

main();
[/perl]

And the output is

[bash]
$ perl convert.pl
02/01/2011 12:02:00 – 3650 secs (YYMMDD HHMMSS) = 110201 110110
3650 secs in HHMMSS format is = 010050
[/bash]

Now, what I did not found searching the web was an easy method to convert seconds¬†to a hour:minute:second format. This forced me to write my own algorithm which, hopefully, is bug free ūüėÄ
[perl]
sub FormatTime($)
{
my ($seconds, $hours, $mins, $secs) = shift;

$hours = padLeft(int($seconds / 3600));
$mins = padLeft($hours == 0 ? int($seconds / 60) : int(($seconds – ($hours * 3600)) / 60));
$secs = padLeft($hours == 0 && $mins == 0 ? $seconds : $seconds % 60);
return “$hours$mins$secs”;
}
[/perl]

What would a portability freak say?

It would probably say that my solution ignores the portability features of Perl. Yes, it is true but I don’t really care since my target is, and will always be, Unix based machines.

 

Software development, times and costs

Time estimation in software development is probably the most difficult part for me when it comes to starting projects independently.

I studied this subject back in university but the classes were never accurate enough to reflex real world examples and I just can blame the teacher for using a 20 years old book talking about failures of WINWORD 1.0, IBM OS/2 and what the hell. The tools has changed, the people has changed and the programming paradigms too. I don’t know if I was doing something wrong but I never found useful any of these so called “techniques” to estimate cost in building software.

Every time a potential client comes to me asking for a solution I¬†analyse the complexity of the project, the possible time I would have to spend in order to get it done, the time he’s giving me and the situation of the marketplace for the kind of software he’s asking for. Clients always come with “I have this problem, I need it fixed, how much for that?”, and they expect an answer immediately and you just have no time to open your spreadsheet and fill it with the variables.

All the techniques I learned at university doesn’t work as I expected. They are just too old or were designed for major software companies with dozens of developers and not for the rest of the people working independently or with a team of 2 or 3 people as much.

My algorithm has some failures. The client sometimes makes last time changes and since a commitment contract was not signed and was all verbally agreed, you can’t say no because you won’t get paid. It is almost a 100% sure that if you, an independent software developer living at Paraguay, try to make your client sign an agreement paper, he will run away :D.

I have a full time job but I also work as an external consultant in my spare time and I have to deal with these kind of situations very often.