slides.vroom

# This is a sample Vroom input file. It should help you get started.
#
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# the show!
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---- config
# Basic config options.
title: Perl sysadmin stuff (Jesse Thompson)
indent: 5
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# vim: gvim
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#   colorscheme default

----
Jesse Thompson
UW Madison
Division of Information Technology

(Email, Calendar, Chat, Subversion, ...)
----
Perl!

sysadminy stuff...
----
something I've just started using...
----
Compile Perl with: -Duserelocatableinc

Use Relocatable INC

Allows you to move perl to another directory.
---- 
How to do it?

> ./Configure \
    -Dprefix=/opt/perl-5.14.2 \
    -des \
    -Duserelocatableinc 

> # install some cpan modules...

> sudo mv /opt/perl-5.14.2 \
          /opt/perl-5.14.2-WithMyAppDeps-YYMMDD
----

1. in dev:  build base perl,
            install your module dependencies
            rename it to something unique
            tarball the whole smash

2. in test: unpack tarball 
            configure app to use new perl path
            test/QA your app

3. in prod: unpack tarball
            configure app to use new perl path
----
Easy backout failed upgrades...

   App uses: #!/opt/perl/bin/perl

   # upgrade perl and dependencies

   > ln -s /opt/perl-5.14.2-20111108 /opt/perl

   # OH NO!  everything is broken!

   > ln -s /opt/perl-5.14.2-20110421 /opt/perl

   # WHEW
----
IN PRODUCTION:

Stay away from 
installing modules directly from CPAN


  What if CPAN modules change 
  (and break your app)
  between dev -> test -> prod 
----
Other advantages:

  No need for local::lib, fatpack, PAR
              and other workarounds.  
    * Just install CPAN modules normally.

  Easily back out to older rev.  
    * Just change the perl that your app uses.

  Production deployments are done at off-hours 
  when you are likely to make a mistake.
----
Problems

  Some executables installed via ExtUtils::MakeMaker 
  will have the wrong #!perl path 

  Maybe others too, but I haven't found them yet.
----
new topic
----
instead of grep and cut (and awk and sed and ...)

     USE PERL :-)
----
grep is handy
but its matching capabilities suck


egrep?
getting there... 
but still not as good as perl regex
---- perl,i4
> cat file | perl -pe 's/.* IPADDR=(.*?) .*/$1/g'
209.85.225.99
209.85.225.105
209.85.225.147

# I can't ever remember how to do things 
# like that using shell tools
# I have to look it up every time
----
command line perl is very handy

not going to go into it all

just think of perl whenever you need
to do any fancy shell scripting

I always end up rewriting all of my
shell script into perl eventually
after they get too complex
----
grepl

    A handy script that works like grep
    but gives you the power of perl regex

SEE ALSO 

    perldoc perlretut
---- perl,i4
#!/usr/bin/perl

# regex is the first argument
#
# if there are more arguments, 
# then it will treat them as files to read
#    e.g. grepl foo myfile.txt
#
# otherwise it reads from STDIN
#    e.g. cat myfile.txt | grepl foo

my $pattern = shift @ARGV;
while ( my $line = <> ) {
    # ...
}
---- perl,i4
  if ( my @matched = $line =~ m{$pattern} ) {

    # there were captures in the regex
    # so display what was captured
    if ( scalar @matched and $matched[0] ne '1' ) {
      print join(' ', @matched), "\n";
    }

    # otherwise the regex just matched on a line
    # so display the whole line
    else {
      print $line;
    }
  }
---- perl,i4
#




# for example:

# grepl murder slipsum.txt



















# (ignore this)
print `echo "> cat slipsum.txt;\n"; cat slipsum.txt; echo "\n> grepl murder slipsum.txt\n"; ./grepl murder slipsum.txt`;
---- perl,i4
#




# for example:

# cat slipsum.txt | grepl ice

















# (ignore this)
print `echo "> cat slipsum.txt;\n"; cat slipsum.txt; echo "\n> cat slipsum.txt | grepl ice\n"; cat slipsum.txt | ./grepl ice`;
---- perl,i4
#




# for example:

# grepl "(\w+) made it out" slipsum.txt


















# (ignore this)
print `echo "> cat slipsum.txt;\n"; cat slipsum.txt; echo "\n> grepl \\"\(\\w+\) made it out\\" slipsum.txt\n" ;./grepl \" (\\w+) made it out\" slipsum.txt`;
---- perl,i4
#




# for example:

# grepl "(\w+) made it (out)" slipsum.txt


















# (ignore this)
print `echo "> cat slipsum.txt;\n"; cat slipsum.txt; echo "\n> grepl \\"\(\\w+\) made it \(out\)\\" slipsum.txt\n" ;./grepl \" (\\w+) made it (out)\" slipsum.txt`;
----
etc
----
new topic
----
overwrite a file using:

    sysopen()
    flock()
    seek()
    truncate()
    tell()
----
fcntl 

    C library

    for manipulating file descriptors
---- perl,i4
use Fcntl qw(:DEFAULT :flock);

# open file for reading and writing
# and create it if needed 
sysopen( my $fh, $file, O_RDWR|O_CREAT ) 
    or die "can't open! $!";

# lock the file 
# so that other instances of this script will die
flock( $fh, LOCK_EX ) 
    or die "can't lock! $!";
---- perl,i4
# seek to the beginning of the file
seek( $fh, 0, 0);

# print some data
print $fh "blah blah blah";

# truncate the file 
# to where we stopped writing
truncate( $fh, tell($fh) );

# close releases the lock
close( $fh );
----
another example!
----
example: cat a log file starting at last position

    memtail
----
something a bit more complex...
----
logcat
----
Specify a time interval,
using both relative and absolute times,
and common language...
to display log lines, 
within that interval,
from multiple files,
in order,
efficiently
----
what does logcat use?

   Time::ParseDate
   File::SortedSeek
---- perl
Time::ParseDate

   Recognizes any date and time format, 
   absolute or relative
---- perl,i4
$seconds = parsedate("Mon Jan  2 04:24:27 1995");
$seconds = parsedate("Tue Apr 4 00:22:12 PDT 1995");
$seconds = parsedate("04.04.95 00:22", ZONE => PDT);
$seconds = parsedate("Jan 1 1999 11:23:34.578", SUBSECOND => 1);
$seconds = parsedate("122212 950404", ZONE => PDT, TIMEFIRST => 1);
$seconds = parsedate("+3 secs", NOW => 796978800);
$seconds = parsedate("2 months", NOW => 796720932);
$seconds = parsedate("last Tuesday");
($seconds, $remaining) = parsedate("today is the day");
($seconds, $error) = parsedate("today is", WHOLE=>1);
---- perl
File::SortedSeek

   fast access to large files
---- perl,i4
  use File::SortedSeek ':all';
  open BIG, $file or die $!;

  # find a number or the first number greater 
  # in a file (ascending order)
  $tell = numeric( *BIG, $number );

  # optional argument is a reference 
  # to a subroutine to munge the file lines 
  # so that suitable values are extracted 
  # for comparison to $find
  $tell = numeric( *BIG, $find, \&munge_line );
----
how does logcat work?
----
e.g.

   logcat \
       --log_name_re="access_log" \
       --start_time="10 minutes ago" \
       --end_time="now"

   logcat \
       --log_name_re="myapp" \
       --relative_time="3 days ago"
       --start_time="start of today" \
       --end_time="end of today" \
---- perl,i4
# setup

my $relative_time = parsedate($args{relative_time});


my $start_time    = parsedate($args{start_time}, 
                              NOW => $relative_time);


my $end_time      = parsedate($args{end_time},   
                              NOW => $relative_time);
---- perl,i4
# get the log files that match the specified name
# and have been modified sometime in the time window

for ( @log_dirs ) {

  opendir my $logdir, $_;

  for my $file ( 

    grep m/$args{log_name_re}/i, readdir $logdir 

  ) {

       ...
---- perl,i4

# exclude the ones that haven't been modified 
# after the beginning of the target day
my ($mtime) = (stat("$_/$file"))[9];
next if ( $mtime < $start_time ); 

# save the last-modified time 
# so that we can sort the files
$log_files{"$_/$file"} = $mtime;
---- perl,i4
# sort the log files 
# so that they are printed in chronological order

return sort { 
    $log_files{$a} <=> $log_files{$b} 
} keys %log_files;
---- perl,i4
# open each log file

for my $logfile ( @log_files ) {
  open my $fh, $logfile;

---- perl,i4
# find the first line at or after the start time

File::SortedSeek::numeric( 
  $fh, 
  $start_time, 
  sub { parse_log_time($_) } 
);

my $start_point = tell($fh);

my $start_line  = <$fh>;
---- perl,i4
# make sure that log lines were found...

if ( ! $start_line 
       or 
     parse_log_time($start_line) > $end_time 
) {
  # no lines in this file
  next;
}
---- perl,i4
# find the last line

File::SortedSeek::numeric( 
  $fh, 
  $end_time, 
  sub { parse_log_time($_) }
);

my $end_point = tell($fh);

my $end_line = <$fh>;
---- perl,i4
# seek to the start line

seek($fh, $start_point, 0);

# print all lines 
while ( my $line = <$fh> ) {
   print $line;
   ...

   # until we reach the end ...
   last if ( tell($fh) >= $end_point );
----
so, what is parse_log_time()???

Time::ParseDate is smart, 
but you need to help it out

you need to parse out the date/time information 

this is kind of a kludge...
---- perl,i4
# Time::ParseDate gives it the line to parse
# we need to return just the date/time info

sub parse_log_time {
  my $line = shift;
  chomp($line);
  my $munged;

---- perl,i4
# UGH, this is too manual
# because there are so many date/time formats

# 20-Aug-2009 11:03:52.12
if ( $line =~ /^(\d+\-\w+\-\d+\s+\d+\:\d+\:\d+\.\d+)\s/ ) {
  $munged = $1;
}

# 216.180.217.126 - - [20/Aug/2009:11:03:52 -0500] 
if ( $line =~ /^[\d\.]+\s+\-\s+\S+\s+\[(\d+\/\w+\/\d+\:\d+\:\d+\:\d+\s+[\-\+]\d+)\]\s/ ) {
  $munged = $1;
}
# 20092008 110352
if ( $line =~ /^(\d{4})(\d{2})(\d{2})\s(\d{2})(\d{2})(\d{2})\s/ ) {
    $munged = "$1/$2/$3 $4:$5:$6";
}
# [20/Aug/2009:11:03:52 -0500]
if ( $line =~ /^\[(\d+\/\w+\/\d+\:\d+\:\d+\:\d+\s+[\-\+]\d+)\]/ ) {
    $munged = $1;
}
# 2009-08-20T11:03:52
if ( $line =~ /^(\d+\-\d+\-\d+T\d+\:\d+\:\d+)\s+/ ) {
    $munged = $1;
}
# [Thu Aug 20 11:03:52 2009]
if ( $line =~ /^\[(\w+\s+\w+\s+\d+\s+\d+\:\d+\:\d+\s+\d+)\]\s+/ ) {
    $munged = $1;
}
# Aug 20 11:03:52
if ( $line =~ /^(\w+\s+\d+\s+\d+\:\d+:\d+)\s+/ ) {
    $munged = $1;
}
# =INFO REPORT==== 2009-08-20 11:03:52 ===
if ( $line =~ /^[\=\s\w]+\s+(\d+\-\d+\-\d+\s+\d+\:\d+\:\d+)\s+/ ) {
    $munged = $1;
}
# [20-Aug-2009 11:03:52]
if ( $line =~ /^\[(\d+\-\w+\-\d+\s+\d+\:\d+\:\d+)\]\s+/ ) {
    $munged = $1;
}
# Aug 20 2009 11:03:52 
if ( $line =~ /^(\w+\s+\d+\s+\d+\s+\d+\:\d+\:\d+)\s+/ ) {
    $munged = $1;
}
# [Wed Aug 20 11:03:52 2009] 
if ( $line =~ /^\[(\w+\s+\w+\d+\s+\d+\:\d+\:\d+\s+\d+)\]\s+/ ) {
    $munged = $1;
}
# 2010/08/16 15:16:41
if ( $line =~ /^(\d+\/\d+\/\d+\s+\d+\:\d+\:\d+)\s+/ ) {
    $munged = $1;
}
# 2011-05-20 11:58:35
if ( $line =~ /^(\d+\-\d+\-\d+\s+\d+\:\d+\:\d+)\s+/ ) {
    $munged = $1;
}
---- perl,i4
# run the parsed date/time through Parse::TimeDate

return parsedate($munged);
----
Anyone got a better way to do that part?
----
THE END
----
VROOM (Ingy döt Net)
----
== Slideshows in Vim

* Hate using PowerPoint or HTML Slides for Talks?
+* Use Vroom!

+* You can write you slides in Vim...
* ...and present them in Vim!

----
== Getting Started

* Write a file called 'slides.vroom'.
  * Do this in a new directory.
* Run 'vroom --vroom'.
* Voilà!

----
== Navigation

* Hit <SPACE> to move forward.
* Hit <BACKSPACE> to go backwards.
* Hit 'Q' to quit.

---- perl,i4
# This is some Perl code.
# Notice the syntax highlighting.
# Run it with the <RR> vim command.
for my $word (qw(Vroom totally rocks!)) {
    print "$word\n";
}

----
== Get Vroom!

* http://search.cpan.org/dist/Vroom/
* http://github.com/ingydotnet/vroom-pm/

----
== Vroom as HTML

* http://ingydotnet.github.com/vroom-pm/

----
== The End