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joko |
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#!/usr/bin/perl -w |
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# $Id: followtail.perl,v 1.8 2001/05/07 12:23:04 rcaputo Exp $ |
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# This program tests Wheel::FollowTail. The FollowTail wheel provides |
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# a reusable "tail -f" behavior for drivers and filters. |
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# NOTE: sessions.perl, objsessions.perl, and packagesessions.perl have |
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# better comments for the basic stuff. |
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use strict; |
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#use lib '..'; |
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#sub POE::Kernel::ASSERT_DEFAULT () { 1 } |
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#sub POE::Kernel::TRACE_DEFAULT () { 1 } |
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use POE qw(Wheel::FollowTail Driver::SysRW Filter::Line Wheel::ReadWrite); |
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use IO::File; |
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#============================================================================== |
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# used to keep track of file names |
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#my @names; |
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# the names of sessions to create |
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#my @numbers = qw(one two three four five six seven eight nine ten); |
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#------------------------------------------------------------------------------ |
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# Create twenty sessions: ten log generators and ten log followers. |
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# The generators periodically write a line of information to their |
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# respective logs. The followers detect that the logs have new |
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# information and display it. |
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#for my $j (0..9) { |
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# call the sessions by name |
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#my $i = $numbers[$j]; |
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# create temporary filenames |
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my $name = 'c:\var\home\amo\.mjamcmd'; |
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### create a log follower |
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POE::Session->new |
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( '_start' => sub |
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{ my ($kernel, $session, $heap) = @_[KERNEL, SESSION, HEAP]; |
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#$heap->{'id'} = $i; |
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# try to open the file |
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if (defined(my $handle = IO::File->new("<$name"))) { |
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# start following the file's tail |
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#$handle->blocking(1); |
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$heap->{'wheel'} = POE::Wheel::FollowTail->new |
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( 'Handle' => $handle, # follow this handle |
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#'Driver' => POE::Driver::SysRW->new, # use sysread to read |
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#'Filter' => POE::Filter::Line->new, # file contains lines |
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'InputEvent' => 'got a line', # input handler |
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'ErrorEvent' => 'error reading', # error handler |
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'PollInterval' => 1, |
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'SeekBack' => 5, |
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); |
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print "reader started", "\n"; |
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use Data::Dumper; |
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print Dumper($heap->{'wheel'}); |
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} |
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# could not read the file |
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else { |
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print "Reader $heap->{'id'} can't open $name for reading: $!\n"; |
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} |
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}, |
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# close and destroy the log filehandle |
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'_stop' => sub |
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{ my $heap = $_[HEAP]; |
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delete $heap->{'wheel'}; |
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print "Reader $heap->{'id'} has stopped.\n"; |
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}, |
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# error handler |
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'error reading' => sub |
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{ my ($heap, $operation, $errnum, $errstr) = @_[HEAP, ARG0, ARG1, ARG2]; |
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print( "Reader ",$heap->{'id'}, |
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" encountered $operation error $errnum: $errstr.\n" |
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); |
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# removes the session's purpose to live |
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delete $heap->{'wheel'}; |
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}, |
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# input handler |
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'got a line' => sub |
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{ my $line_of_input = $_[ARG0]; |
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# just display the input |
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print "got line: "; |
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print $line_of_input, "\n"; |
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}, |
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# To catch strange events. |
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_default => |
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sub { |
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warn "default caught $_[ARG0] with (@{$_[ARG1]})"; |
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my $i = 0; |
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while (1) { |
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my @xyz = map { defined($_) ? $_ : '(undef)' } caller($i++); |
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$xyz[-1] = unpack 'B*', $xyz[-1]; |
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last unless @xyz; |
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warn "$i: @xyz\n"; |
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} |
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return 0; |
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}, |
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); |
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#} |
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#------------------------------------------------------------------------------ |
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# This session is just a busy loop that prints a message every half |
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# second. It does this to ensure that the other twenty sessions are |
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# not blocking while waiting for input. |
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POE::Session->new |
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( _start => sub |
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{ my ($kernel, $session) = @_[KERNEL, SESSION]; |
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$kernel->post($session, 'spin a wheel'); |
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}, |
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'spin a wheel' => sub |
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{ my $kernel = $_[KERNEL]; |
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print "*** spin! ***\n"; |
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$kernel->delay_add('spin a wheel', 2); |
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}, |
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); |
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#============================================================================== |
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# Run the kernel until all the sessions die (SIGINT, most likely). |
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# When done, unlink the temporary files in @names. |
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$poe_kernel->run(); |
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# The temporary files are unlinked out here because some systems |
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# (notably DOSISH ones) don't allow files to be unlinked while they |
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# are open. |
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#unlink @names; |
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exit; |
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