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=head1 NAME |
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AnyEvent::Debug - debugging utilities for AnyEvent |
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=head1 SYNOPSIS |
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use AnyEvent::Debug; |
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# create an interactive shell into the program |
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my $shell = AnyEvent::Debug::shell "unix/", "/home/schmorp/myshell"; |
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# then on the shell: "socat readline /home/schmorp/myshell" |
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=head1 DESCRIPTION |
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This module provides functionality hopefully useful for debugging. |
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At the moment, "only" an interactive shell is implemented. This shell |
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allows you to interactively "telnet into" your program and execute Perl |
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code, e.g. to look at global variables. |
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=head1 FUNCTIONS |
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=over 4 |
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=cut |
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package AnyEvent::Debug; |
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use Errno (); |
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use AnyEvent (); BEGIN { AnyEvent::common_sense } |
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use AnyEvent::Util (); |
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use AnyEvent::Socket (); |
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=item $shell = AnyEvent;::Debug::shell $host, $service |
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This function binds on the given host and service port and returns a |
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shell object, whcih determines the lifetime of the shell. Any number |
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of conenctions are accepted on the port, and they will give you a very |
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primitive shell that simply executes every line you enter. |
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All commands will be executed "blockingly" with the socket C<select>ed for |
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output. For a less "blocking" interface see L<Coro::Debug>. |
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The commands will be executed in the C<AnyEvent::Debug::shell> package, |
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which is initially empty and up to use by all shells. Code is evaluated |
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under C<use strict 'subs'>. |
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Consider the beneficial aspects of using more global (our) variables than |
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local ones (my) in package scope: Earlier all my modules tended to hide |
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internal variables inside C<my> variables, so users couldn't accidentally |
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access them. Having interactive access to your programs changed that: |
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having internal variables still in the global scope means you can debug |
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them easier. |
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As no authenticsation is done, in most cases it is best not to use a TCP |
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port, but a unix domain socket, whcih cna be put wherever youc an access |
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it, but not others: |
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our $SHELL = AnyEvent::Debug::shell "unix/", "/home/schmorp/shell"; |
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Then you can use a tool to connect to the shell, such as the ever |
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versatile C<socat>, which in addition can give you readline support: |
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socat readline /home/schmorp/shell |
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# or: |
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cd /home/schmorp; socat readline unix:shell |
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Socat can even give you a persistent history: |
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socat readline,history=.anyevent-history unix:shell |
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Binding on C<127.0.0.1> (or C<::1>) might be a less secure but sitll not |
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totally insecure (on single-user machines) alternative to let you use |
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other tools, such as telnet: |
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our $SHELL = AnyEvent::Debug::shell "127.1", "1357"; |
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And then: |
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telnet localhost 1357 |
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=cut |
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sub shell($$) { |
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AnyEvent::Socket::tcp_server $_[0], $_[1], sub { |
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my ($fh, $host, $port) = @_; |
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syswrite $fh, "Welcome, $host:$port!\015\012> "; |
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my $rbuf; |
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my $rw; $rw = AE::io $fh, 0, sub { |
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my $len = sysread $fh, $rbuf, 1024, length $rbuf; |
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if (defined $len ? $len == 0 : $! != Errno::EAGAIN) { |
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undef $rw; |
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} else { |
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while ($rbuf =~ s/^(.*)\015?\012//) { |
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my $line = $1; |
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AnyEvent::Util::fh_nonblocking $fh, 0; |
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if ($line =~ /^\s*exit\b/) { |
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syswrite $fh, "sorry, no... if you want to execute exit, try CORE::exit.\015\012"; |
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} else { |
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package AnyEvent::Debug::shell; |
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no strict 'vars'; |
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my $old_stdout = select $fh; |
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local $| = 1; |
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my @res = eval $line; |
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select $old_stdout; |
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syswrite $fh, "$@" if $@; |
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syswrite $fh, "\015\012"; |
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if (@res > 1) { |
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syswrite $fh, "$_: $res[$_]\015\012" for 0 .. $#res; |
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} elsif (@res == 1) { |
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syswrite $fh, "$res[0]\015\012"; |
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} |
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} |
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syswrite $fh, "> "; |
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AnyEvent::Util::fh_nonblocking $fh, 1; |
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} |
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} |
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1.3 |
}; |
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1.1 |
} |
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} |
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1; |
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=back |
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=head1 AUTHOR |
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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=cut |
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