Forum: Ruby Generating a report from an ugly log file

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Srijayanth S. (Guest)
on 2009-04-27 14:36
(Received via mailing list)
Hello,

I have the following problem.

There exists a really ugly debug log file which has mysql query
statements.
Looking through the log makes it hard to understand esp while providing
reports to bosses/mgrs etc. so I have decided to make it more "English".
I
have over 40 queries, each that can be called in different ways, for
instance:

1) select foo1, foo2 from foo where foo1=... etc
2) select foo1 from foo where foo1= etc

The basic parsing would be
/select(.*)\s+from\s+(.*)(?:\s+where\s+(.*)$)/ #
its a bit more advanced, but its solved and hence not a problem

#captures[1] will be the table name

1) Each table/view is its own class with a to_english method that does
the
translation
2) An abstract class that parses a line from the log file, extracts the
table or view (in this case foo) from the match and generates an object
using eval "#{table.capitalize}.new captures"
3) The to_english method generates an English representation of the
object
based on logic that uses information from the various captures passed
in.

The idea is to have a list of objects that I iterate over and do a
#to_english

My questions are:

1) Should I organize this differently and run away from eval?
2) Since there are over 40 odd classes, is there a better way to require
them other than:

Dir.glob("qry*").each { |r| require r }

Thank you,

Jayanth
Mark T. (Guest)
on 2009-04-27 21:10
(Received via mailing list)
On Apr 27, 6:35 am, Srijayanth S. <removed_email_address@domain.invalid> wrote:
> instance:
> translation
Do you really need this? It may be overkill if the only thing you will
do in each of these classes is a to_english method. You could perhaps
use a singleton class that contains all the translations.

> 2) An abstract class that parses a line from the log file, extracts the
> table or view (in this case foo) from the match and generates an object
> using eval "#{table.capitalize}.new captures"

To avoid eval, use
  Kernel.const_get(table.capitalize).send(:to_english)
where to_english is a class method.
Srijayanth S. (Guest)
on 2009-04-27 21:50
(Received via mailing list)
Thanks.

Unfortunately, I plan to do more than just to_english. The logs have
information that is also dependent on the ordering of the mysql
statements
themselves, so I want to be able to map queries based on certain
conditions
etc, so no running away from it really, but the Kernel#const_get#send is
a
nice option.

Jayanth
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