Files
percona-toolkit/lib/Cxn.pm
2012-10-08 12:53:54 -06:00

237 lines
8.1 KiB
Perl

# This program is copyright 2011 Percona Inc.
# Feedback and improvements are welcome.
#
# THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
# MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation, version 2; OR the Perl Artistic License. On UNIX and similar
# systems, you can issue `man perlgpl' or `man perlartistic' to read these
# licenses.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc., 59 Temple
# Place, Suite 330, Boston, MA 02111-1307 USA.
# ###########################################################################
# Cxn package
# ###########################################################################
{
# Package: Cxn
# Cxn creates and properly initializes a MySQL connection. This class
# encapsulates connections for several reasons. One, initialization
# may involve setting or changing several things, so centralizing this
# guarantees that each cxn is properly and consistently initialized.
# Two, the class's deconstructor (DESTROY) ensures that each cxn is
# disconnected even if the program dies unexpectedly. Three, when a cxn
# is lost and re-connected, accessing the dbh via the sub dbh() instead
# of via the var $dbh ensures that the program always uses the new, correct
# dbh. Four, by encapsulating a cxn with subs that manage that cxn,
# the receiver of a Cxn obj can re-connect the cxn if it's lost without
# knowing how that's done (and it shouldn't know; that's not its job).
package Cxn;
use strict;
use warnings FATAL => 'all';
use English qw(-no_match_vars);
use Scalar::Util qw(blessed);
use constant {
PTDEBUG => $ENV{PTDEBUG} || 0,
# Hostnames make testing less accurate. Tests need to see
# that such-and-such happened on specific slave hosts, but
# the sandbox servers are all on one host so all slaves have
# the same hostname.
PERCONA_TOOLKIT_TEST_USE_DSN_NAMES => $ENV{PERCONA_TOOLKIT_TEST_USE_DSN_NAMES} || 0,
};
# Sub: new
#
# Required Arguments:
# DSNParser - <DSNParser> object
# OptionParser - <OptionParser> object
# dsn - DSN hashref, or...
# dsn_string - ... DSN string like "h=127.1,P=12345"
#
# Optional Arguments:
# dbh - Pre-created, uninitialized dbh
# set - Callback to set vars on dbh when dbh is first connected
#
# Returns:
# Cxn object
sub new {
my ( $class, %args ) = @_;
my @required_args = qw(DSNParser OptionParser);
foreach my $arg ( @required_args ) {
die "I need a $arg argument" unless $args{$arg};
};
my ($dp, $o) = @args{@required_args};
# Any tool that connects to MySQL should have a standard set of
# connection options like --host, --port, --user, etc. These
# are default values; they're used in the DSN if the DSN doesn't
# explicate the corresponding part (h=--host, P=--port, etc.).
my $dsn_defaults = $dp->parse_options($o);
my $prev_dsn = $args{prev_dsn};
my $dsn = $args{dsn};
if ( !$dsn ) {
# If there's no DSN and no DSN string, then the user probably ran
# the tool without specifying a DSN or any default connection options.
# They're probably relying on DBI/DBD::mysql to do the right thing
# by connecting to localhost. On many systems, connecting just to
# localhost causes DBI to use a built-in socket, i.e. it doesn't
# always equate to 'h=127.0.0.1,P=3306'.
$args{dsn_string} ||= 'h=' . ($dsn_defaults->{h} || 'localhost');
$dsn = $dp->parse(
$args{dsn_string}, $prev_dsn, $dsn_defaults);
}
elsif ( $prev_dsn ) {
# OptionParser doesn't make DSN type options inherit values from
# a command line DSN because it doesn't know which ARGV from the
# command line are DSNs or other things. So if the caller wants
# DSNs to inherit values from a prev DSN (i.e. one from the
# command line), then they must pass it as the prev_dsn and we
# copy values from it into this new DSN, resulting in a new DSN
# with values from both sources.
$dsn = $dp->copy($prev_dsn, $dsn);
}
my $self = {
dsn => $dsn,
dbh => $args{dbh},
dsn_name => $dp->as_string($dsn, [qw(h P S)]),
hostname => '',
set => $args{set},
NAME_lc => defined($args{NAME_lc}) ? $args{NAME_lc} : 1,
dbh_set => 0,
OptionParser => $o,
DSNParser => $dp,
is_cluster_node => undef,
};
return bless $self, $class;
}
sub connect {
my ( $self ) = @_;
my $dsn = $self->{dsn};
my $dp = $self->{DSNParser};
my $o = $self->{OptionParser};
my $dbh = $self->{dbh};
if ( !$dbh || !$dbh->ping() ) {
# Ask for password once.
if ( $o->get('ask-pass') && !$self->{asked_for_pass} ) {
$dsn->{p} = OptionParser::prompt_noecho("Enter MySQL password: ");
$self->{asked_for_pass} = 1;
}
$dbh = $dp->get_dbh($dp->get_cxn_params($dsn), { AutoCommit => 1 });
}
PTDEBUG && _d($dbh, 'Connected dbh to', $self->{name});
return $self->set_dbh($dbh);
}
sub set_dbh {
my ($self, $dbh) = @_;
# If we already have a dbh, and that dbh is the same as this dbh,
# and the dbh has already been set, then do not re-set the same
# dbh. dbh_set is required so that if this obj was created with
# a dbh, we set that dbh when connect() is called because whoever
# created the dbh probably didn't set what we set here. For example,
# MasterSlave makes dbhs when finding slaves, but it doesn't set
# anything.
if ( $self->{dbh} && $self->{dbh} == $dbh && $self->{dbh_set} ) {
PTDEBUG && _d($dbh, 'Already set dbh');
return $dbh;
}
PTDEBUG && _d($dbh, 'Setting dbh');
# Set stuff for this dbh (i.e. initialize it).
$dbh->{FetchHashKeyName} = 'NAME_lc' if $self->{NAME_lc};
# Update the cxn's name. Until we connect, the DSN parts
# h and P are used. Once connected, use @@hostname.
my $sql = 'SELECT @@hostname, @@server_id';
PTDEBUG && _d($dbh, $sql);
my ($hostname, $server_id) = $dbh->selectrow_array($sql);
PTDEBUG && _d($dbh, 'hostname:', $hostname, $server_id);
if ( $hostname ) {
$self->{hostname} = $hostname;
}
# Call the set callback to let the caller SET any MySQL variables.
if ( my $set = $self->{set}) {
$set->($dbh);
}
$self->{dbh} = $dbh;
$self->{dbh_set} = 1;
return $dbh;
}
# Sub: dbh
# Return the cxn's dbh.
sub dbh {
my ($self) = @_;
return $self->{dbh};
}
# Sub: dsn
# Return the cxn's dsn.
sub dsn {
my ($self) = @_;
return $self->{dsn};
}
# Sub: name
# Return the cxn's name.
sub name {
my ($self) = @_;
return $self->{dsn_name} if PERCONA_TOOLKIT_TEST_USE_DSN_NAMES;
return $self->{hostname} || $self->{dsn_name} || 'unknown host';
}
sub is_cluster_node {
my ($self) = @_;
return $self->{is_cluster_node} if defined $self->{is_cluster_node};
my $sql = "SHOW VARIABLES LIKE 'wsrep_on'";
PTDEBUG && _d($sql);
my $row = $self->{dbh}->selectrow_arrayref($sql);
PTDEBUG && _d(defined $row ? @$row : 'undef');
$self->{is_cluster_node} = $row && $row->[1]
? ($row->[1] eq 'ON' || $row->[1] eq '1')
: 0;
return $self->{is_cluster_node};
}
sub DESTROY {
my ($self) = @_;
if ( $self->{dbh}
&& blessed($self->{dbh})
&& $self->{dbh}->can("disconnect") ) {
PTDEBUG && _d('Disconnecting dbh', $self->{dbh}, $self->{name});
$self->{dbh}->disconnect();
}
return;
}
sub _d {
my ($package, undef, $line) = caller 0;
@_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }
map { defined $_ ? $_ : 'undef' }
@_;
print STDERR "# $package:$line $PID ", join(' ', @_), "\n";
}
1;
}
# ###########################################################################
# End Cxn package
# ###########################################################################