Question about file management

A salut to the list,

I need read info from a file, extract the info that I want which is the
date and IP and dump them into a database (mysql).

However, this file gets constantly updated, sits on /var/log/.

Until now I have used just the file.open and file.read methods. However,
I feel that both ways are not suitable for what I want to do, because I
will need to make a selection between old and new entries every time my
script reads the file to extract info.

What is the standard (or best) way to manage this situation?

Here is the class which reads the file:

class ReadIPs
def self.ip(log)
file = File.open(log)
file.each_line do |line|
if line.include?(“Ban”)
a = line.split(" ")
date = a[0]
ip = a[6]
puts “date: #{date} IP: #{ip}”
end
end
file.close
end
end

I use File.open now but I should use something like File.append or
similar? Note that I will never write to this file, it’s just the file
that contains the info. Every time a new line appears that contains the
word “Ban” I want to trigger this…

Best regards

Panagiotis (atmosx) Atmatzidis

email: [email protected]
URL: http://www.convalesco.org
GnuPG ID: 0xFC4E8BB4
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On 12.12.2009 21:05, Panagiotis A. wrote:

Here is the class which reads the file:

class ReadIPs
def self.ip(log)
file = File.open(log)

Ha! There you are not using block form of File.open and you do not have
the #close in ensure! :slight_smile:

end

I use File.open now but I should use something like File.append or similar? Note that I will never write to this file, it’s just the file that contains the info. Every time a new line appears that contains the word “Ban” I want to trigger this…

Best regards

I can’t test it right now but this might be an option.

File.open log do |io|
loop do
io.each do |line|
# whatever…
end

 # v2: pos = io.tell
 sleep 10 # whatever interval is appropriate
 # v1: io.seek(0, IO::SEEK_SET)
 # v2: io.seek(pos, IO::SEEK_CUR)

end
end

Maybe you have to do one of the variants to clear eof flag:

v1: seek to offset 0 of current position
v2: fetch the position before the sleep and then seek to that absolute
position

Kind regards

robert

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Hello,

On 13 Δεκ 2009, at 1:20 μ.μ., Robert K. wrote:

Here is the class which reads the file:

class ReadIPs
def self.ip(log)
file = File.open(log)

Ha! There you are not using block form of File.open and you do not have the #close in ensure! :slight_smile:

I don’t understand what do you mean by ‘ensure’.

end
io.each do |line|
Maybe you have to do one of the variants to clear eof flag:

v1: seek to offset 0 of current position
v2: fetch the position before the sleep and then seek to that absolute position

Kind regards

robert

Oh, this solutions, might work but I think that it’s a bit
overcomplicated for me. I did not used IO and “seek” yet…

I found online [1] a few examples but I did not had the time to test
them.

Maybe something like:

file = File.open(path, File::WRONLY|File::APPEND)

Will do.


remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

[1] http://pleac.sourceforge.net/pleac_ruby/fileaccess.html

Panagiotis (atmosx) Atmatzidis

email: [email protected]
URL: http://www.convalesco.org
GnuPG ID: 0xFC4E8BB4
gpg --keyserver x-hkp://pgp.mit.edu --recv-keys 0xFC4E8BB4


The wise man said: “Never argue with an idiot. They bring you down to
their level and beat you with experience.”

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On 13.12.2009 14:37, Panagiotis A. wrote:

What is the standard (or best) way to manage this situation?

Here is the class which reads the file:

class ReadIPs
def self.ip(log)
file = File.open(log)
Ha! There you are not using block form of File.open and you do not have the #close in ensure! :slight_smile:

I don’t understand what do you mean by ‘ensure’.

There full syntax you can have with begin end blocks is

begin
rescue
else
ensure
end

See also
http://blog.rubybestpractices.com/posts/rklemme/002_Writing_Block_Methods.html
http://blog.rubybestpractices.com/posts/rklemme/001-Using_blocks_for_Robustness.html

end
end
v1: seek to offset 0 of current position
v2: fetch the position before the sleep and then seek to that absolute position

Oh, this solutions, might work but I think that it’s a bit overcomplicated for me. I did not used IO and “seek” yet…

#seek is not used in the simplest case. What about reading up on #seek
and #tell or trying out the code? I don’t see where this is
complicated. If that’s too complicated for you then I either my
explanation made it look more complicated that it actually is or you
should abandon software development. You’ll encounter far more
complicated things in the course of it.

I found online [1] a few examples but I did not had the time to test them.

Maybe something like:

file = File.open(path, File::WRONLY|File::APPEND)

Will do.

Will do what?

[1] http://pleac.sourceforge.net/pleac_ruby/fileaccess.html

I am not sure whether pleac is a proper source to enter the world of
ruby. AFAIK their aim is to compare languages - not to present an
introductory read of particular languages. There are quite a few
tutorials and books out there for Ruby.

Kind regards

robert

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hi,

On 13 Δεκ 2009, at 4:35 μ.μ., Robert K. wrote:

Until now I have used just the file.open and file.read methods. However, I feel that both ways are not suitable for what I want to do, because I will need to make a selection between old and new entries every time my script reads the file to extract info.

http://blog.rubybestpractices.com/posts/rklemme/001-Using_blocks_for_Robustness.html
Okay

end
# whatever…

v1: seek to offset 0 of current position
v2: fetch the position before the sleep and then seek to that absolute position

Oh, this solutions, might work but I think that it’s a bit overcomplicated for me. I did not used IO and “seek” yet…

#seek is not used in the simplest case. What about reading up on #seek and #tell or trying out the code? I don’t see where this is complicated. If that’s too complicated for you then I either my explanation made it look more complicated that it actually is or you should abandon software development. You’ll encounter far more complicated things in the course of it.

Given the fact that I’m messing with Ruby less than 8 days, I’ll pass
that note.

By complicated I meant that, ruby might have a build-in function or gem
that already deals with this situation of monitoring etc.

I found online [1] a few examples but I did not had the time to test them.
Maybe something like: file = File.open(path, File::WRONLY|File::APPEND)
Will do.

Will do what?

[1] http://pleac.sourceforge.net/pleac_ruby/fileaccess.html

I am not sure whether pleac is a proper source to enter the world of ruby. AFAIK their aim is to compare languages - not to present an introductory read of particular languages. There are quite a few tutorials and books out there for Ruby.

Okay, thanks

Kind regards

robert


remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

Panagiotis (atmosx) Atmatzidis

email: [email protected]
URL: http://www.convalesco.org
GnuPG ID: 0xFC4E8BB4
gpg --keyserver x-hkp://pgp.mit.edu --recv-keys 0xFC4E8BB4


The wise man said: “Never argue with an idiot. They bring you down to
their level and beat you with experience.”

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