[ViewVC] Diff of: cvs/AnyEvent-DBI/DBI.pm

Comparing AnyEvent-DBI/DBI.pm (file contents):
Revision 1.10 by root, Tue Jun 2 16:16:03 2009 UTC vs.
Revision 1.18 by root, Sun Aug 27 09:54:25 2017 UTC

…		…
9	my $cv = AnyEvent->condvar;	9	my $cv = AnyEvent->condvar;
10		10
11	my $dbh = new AnyEvent::DBI "DBI:SQLite:dbname=test.db", "", "";	11	my $dbh = new AnyEvent::DBI "DBI:SQLite:dbname=test.db", "", "";
12		12
13	$dbh->exec ("select * from test where num=?", 10, sub {	13	$dbh->exec ("select * from test where num=?", 10, sub {
14	my ($rows, $rv) = @_;	14	my ($dbh, $rows, $rv) = @_;
		15
		16	$#_ or die "failure: $@";
15		17
16	print "@$_\n"	18	print "@$_\n"
17	for @$rows;	19	for @$rows;
18		20
19	$cv->broadcast;	21	$cv->broadcast;
…		…
31	This module implements asynchronous DBI access by forking or executing	33	This module implements asynchronous DBI access by forking or executing
32	separate "DBI-Server" processes and sending them requests.	34	separate "DBI-Server" processes and sending them requests.
33		35
34	It means that you can run DBI requests in parallel to other tasks.	36	It means that you can run DBI requests in parallel to other tasks.
35		37
36	The overhead for very simple statements ("select 0") is somewhere	38	With DBD::mysql, the overhead for very simple statements
37	around 120% to 200% (dual/single core CPU) compared to an explicit	39	("select 0") is somewhere around 50% compared to an explicit
38	prepare_cached/execute/fetchrow_arrayref/finish combination.	40	prepare_cached/execute/fetchrow_arrayref/finish combination. With
		41	DBD::SQlite3, it's more like a factor of 8 for this trivial statement.
		42
		43	=head2 ERROR HANDLING
		44
		45	This module defines a number of functions that accept a callback
		46	argument. All callbacks used by this module get their AnyEvent::DBI handle
		47	object passed as first argument.
		48
		49	If the request was successful, then there will be more arguments,
		50	otherwise there will only be the C<$dbh> argument and C<$@> contains an
		51	error message.
		52
		53	A convenient way to check whether an error occurred is to check C<$#_> -
		54	if that is true, then the function was successful, otherwise there was an
		55	error.
39		56
40	=cut	57	=cut
41		58
42	package AnyEvent::DBI;	59	package AnyEvent::DBI;
43		60
44	use strict;	61	use common::sense;
45	no warnings;
46		62
47	use Carp;	63	use Carp;
48	use Socket ();	64	use Convert::Scalar ();
49	use Scalar::Util ();	65	use AnyEvent::Fork ();
50	use Storable ();	66	use CBOR::XS ();
51
52	use DBI ();
53		67
54	use AnyEvent ();	68	use AnyEvent ();
55	use AnyEvent::Util ();	69	use AnyEvent::Util ();
56		70
57	use Errno qw(:POSIX);	71	use Errno ();
58	use Fcntl qw(F_SETFD);
59	use POSIX qw(sysconf _SC_OPEN_MAX);
60		72
61	our $VERSION = '1.2';	73	our $VERSION = '3.01';
62	my $fd_max = 1023; # default
63	eval { $fd_max = sysconf _SC_OPEN_MAX - 1; };
64
65	# this is the forked server code
66
67	our $DBH;
68
69	sub req_open {
70	my (undef, $dbi, $user, $pass, %attr) = @{+shift};
71
72	$DBH = DBI->connect ($dbi, $user, $pass, \%attr) or die $DBI::errstr;
73
74	[1]
75	}
76
77	sub req_exec {
78	my (undef, $st, @args) = @{+shift};
79	my $sth = $DBH->prepare_cached ($st, undef, 1)
80	or die [$DBI::errstr];
81
82	my $rv = $sth->execute (@args)
83	or die [$sth->errstr];
84
85	[1, $sth->{NUM_OF_FIELDS} ? $sth->fetchall_arrayref : undef, { rv => $rv }]
86	}
87
88	sub req_attr {
89	my (undef, $attr_name, $attr_val) = @{+shift};
90
91	if (defined $attr_val) {
92	$DBH->{$attr_name} = $attr_val;
93	}
94
95	[1, $DBH->{$attr_name}]
96	}
97
98	sub req_begin_work {
99	[scalar $DBH->begin_work or die $DBI::errstr]
100	}
101
102	sub req_commit {
103	[scalar $DBH->commit or die $DBI::errstr]
104	}
105
106	sub req_rollback {
107	[scalar $DBH->rollback or die $DBI::errstr]
108	}
109
110	sub req_func {
111	my (undef, $arg_string, $function) = @{+shift};
112	my @args = eval $arg_string;
113
114	if ($@) {
115	die "Bad func() arg string: $@";
116	}
117
118	my $rv = $DBH->func (@args, $function);
119	return [$rv . $DBH->err];
120	}
121
122	sub serve {
123	my ($fileno) = @_;
124
125	open my $fh, ">>&=$fileno"
126	or die "Couldn't open service socket: $!";
127
128	no strict;
129
130	eval {
131	my $rbuf;
132
133	while () {
134	sysread $fh, $rbuf, 16384, length $rbuf
135	or last;
136
137	while () {
138	my $len = unpack "L", $rbuf;
139
140	# full request available?
141	last unless $len && $len + 4 <= length $rbuf;
142
143	my $req = Storable::thaw substr $rbuf, 4;
144	substr $rbuf, 0, $len + 4, ""; # remove length + request
145
146	my $wbuf = eval { pack "L/a*", Storable::freeze $req->[0]($req) };
147	$wbuf = pack "L/a*", Storable::freeze [undef, ref $@ ? "$@->[0]" : $@ , ref $@ ? $@->[1] : 1]
148	if $@;
149
150	for (my $ofs = 0; $ofs < length $wbuf; ) {
151	$ofs += (syswrite $fh, substr $wbuf, $ofs
152	or die "unable to write results");
153	}
154	}
155	}
156	};
157
158	if (AnyEvent::WIN32) {
159	kill 9, $$; # no other way on the broken windows platform
160	# and the above doesn't even work on windows, it seems the only
161	# way to is to leak memory and kill 9 from the parent. yay.
162	}
163
164	require POSIX;
165	POSIX::_exit 0;
166	# and the above kills the parent process on windows
167	}
168
169	sub start_server {
170	serve shift @ARGV;
171	}
172		74
173	=head2 METHODS	75	=head2 METHODS
174		76
175	=over 4	77	=over 4
176		78
…		…
197		99
198	When an error occurs, then this callback will be invoked. On entry, C<$@>	100	When an error occurs, then this callback will be invoked. On entry, C<$@>
199	is set to the error message. C<$filename> and C<$line> is where the	101	is set to the error message. C<$filename> and C<$line> is where the
200	original request was submitted.	102	original request was submitted.
201		103
202	If the fatal argument is true then the database connection shuts down and your	104	If the fatal argument is true then the database connection is shut down
203	database handle becomes invalid. All of your queued request callbacks are	105	and your database handle became invalid. In addition to invoking the
204	called without any arguments.	106	C<on_error> callback, all of your queued request callbacks are called
		107	without only the C<$dbh> argument.
205		108
206	If omitted, then C<die> will be called on any errors, fatal or not.	109	If omitted, then C<die> will be called on any errors, fatal or not.
207		110
208	The C<$dbh> argument is always a weak reference to the AnyEvent::DBI object.
209
210	=item on_connect => $callback->($dbh)	111	=item on_connect => $callback->($dbh[, $success])
211		112
212	If you supply an on_connect callback, then this callback will be invoked after	113	If you supply an C<on_connect> callback, then this callback will be
213	the database connection is attempted. If the connection succeeds, C<$dbh>	114	invoked after the database connect attempt. If the connection succeeds,
214	contains a weak reference to the AnyEvent::DBI object. If the connection fails	115	C<$success> is true, otherwise it is missing and C<$@> contains the
215	for any reason, no arguments are passed to the callback and C<$@> contains
216	$DBI::errstr.	116	C<$DBI::errstr>.
217		117
218	Regardless of whether on_connect is supplied, connect errors will result in	118	Regardless of whether C<on_connect> is supplied, connect errors will result in
219	on_error being called. However, if no on_connect callback is supplied, then	119	C<on_error> being called. However, if no C<on_connect> callback is supplied, then
220	connection errors are considered fatal. The client will die() and the on_error	120	connection errors are considered fatal. The client will C<die> and the C<on_error>
221	callback will be called with C<$fatal> true. When on_connect is supplied,	121	callback will be called with C<$fatal> true.
222	connect error are not fatal and AnyEvent::DBI will not die(). You still
223	cannot, however, use the $dbh object you recived from new() to make requests.
224		122
225	=item exec_server => 1	123	When on_connect is supplied, connect error are not fatal and AnyEvent::DBI
		124	will not C<die>. You still cannot, however, use the $dbh object you
		125	received from C<new> to make requests.
226		126
227	If you supply an exec_server argument, then the DBI server process will call	127	=item fork_template => $AnyEvent::Fork-object
228	something like:
229		128
230	exec "$^X -MAnyEvent::DBI -e AnyEvent::DBI::start_server"	129	C<AnyEvent::DBI> uses C<< AnyEvent::Fork->new >> to create the database
		130	slave, which in turn either C<exec>'s a new process (similar to the old
		131	C<exec_server> constructor argument) or uses a process forked early (see
		132	L<AnyEvent::Fork::Early>).
231		133
232	after forking. This will provide the cleanest possible interpreter for your	134	With this argument you can provide your own fork template. This can be
233	database server. There are special provisions to include C<-Mblib> if the	135	useful if you create a lot of C<AnyEvent::DBI> handles and want to save
234	current interpreter is running with blib.	136	memory (And speed up startup) by not having to load C<AnyEvent::DBI> again
		137	and again into your child processes:
235		138
236	If you do not supply the exec_server argument (or supply it with a false value)	139	my $template = AnyEvent::Fork
237	then the traditional method of starting the server within the same forked	140	->new # create new template
238	interpreter context is used. The forked interpreter will try to clean itself	141	->require ("AnyEvent::DBI::Slave"); # preload AnyEvent::DBI::Slave module
239	up by calling POSIX::close on all filedescriptors except STDIN, STDOUT, and	142
240	STDERR (and the socket it uses to communicate with the cilent, of course).	143	for (...) {
		144	$dbh = new AnyEvent::DBI ...
		145	fork_template => $template;
241		146
242	=item timeout => seconds	147	=item timeout => seconds
243		148
244	If you supply a timeout parameter (floating point number of seconds), then a	149	If you supply a timeout parameter (fractional values are supported), then
245	timer is started any time the DBI handle expects a response from the server.	150	a timer is started any time the DBI handle expects a response from the
246	This includes connection setup as well as requests made to the backend. The	151	server. This includes connection setup as well as requests made to the
247	timeout spans the duration from the moment the first data is written (or queued	152	backend. The timeout spans the duration from the moment the first data
248	to be written) until all expected responses are returned, but is postponed for	153	is written (or queued to be written) until all expected responses are
249	"timeout" seconds each time more data is returned from the server. If the	154	returned, but is postponed for "timeout" seconds each time more data is
250	timer ever goes off then a fatal error is generated. If you have an on_error	155	returned from the server. If the timer ever goes off then a fatal error is
251	handler installed, then it will be called, otherwise your program will die().	156	generated. If you have an C<on_error> handler installed, then it will be
		157	called, otherwise your program will die().
252		158
253	When altering your databases with timeouts it is wise to use transactions. If	159	When altering your databases with timeouts it is wise to use
254	you quit due to timeout while performing insert, update or schema-altering	160	transactions. If you quit due to timeout while performing insert, update
255	commands you can end up not knowing if the action was submitted to the	161	or schema-altering commands you can end up not knowing if the action was
256	database, complicating recovery.	162	submitted to the database, complicating recovery.
257		163
258	Timeout errors are always fatal.	164	Timeout errors are always fatal.
259		165
260	=back	166	=back
261		167
262	Any additional key-value pairs will be rolled into a hash reference and passed	168	Any additional key-value pairs will be rolled into a hash reference
263	as the final argument to the DBI->connect(...) call. For example, to supress	169	and passed as the final argument to the C<< DBI->connect (...) >>
264	errors on STDERR and send them instead to an AnyEvent::Handle you could do:	170	call. For example, to suppress errors on STDERR and send them instead to an
		171	AnyEvent::Handle you could do:
265		172
266	$dbh = new AnyEvent::DBI	173	$dbh = new AnyEvent::DBI
267	"DBI:mysql:test;mysql_read_default_file=/root/.my.cnf", "", "",	174	"DBI:mysql:test;mysql_read_default_file=/root/.my.cnf", "", "",
268	PrintError => 0,	175	PrintError => 0,
		176	on_error => sub {
269	on_error => sub { $log_handle->push_write("DBI Error: $@ at $_[1]:$_[2]\n"); }	177	$log_handle->push_write ("DBI Error: $@ at $_[1]:$_[2]\n");
		178	};
270		179
271	=cut	180	=cut
272
273	# stupid Storable autoloading, total loss-loss situation
274	Storable::thaw Storable::freeze [];
275		181
276	sub new {	182	sub new {
277	my ($class, $dbi, $user, $pass, %arg) = @_;	183	my ($class, $dbi, $user, $pass, %arg) = @_;
278		184
279	socketpair my $client, my $server, &Socket::AF_UNIX, &Socket::SOCK_STREAM, &Socket::PF_UNSPEC	185	# we use our own socketpair, so we always have a socket
		186	# available, even before the forked process exsist.
		187	# this is mostly done so this module is compatible
		188	# to versions of itself older than 3.0.
		189	my ($client, $server) = AnyEvent::Util::portable_socketpair
280	or croak "unable to create dbi communicaiton pipe: $!";	190	or croak "unable to create AnyEvent::DBI communications pipe: $!";
281		191
		192	my $fork = delete $arg{fork_template};
		193
282	my %dbi_args = ( %arg ) ;	194	my %dbi_args = %arg;
283	delete @dbi_args{qw( on_connect on_error timeout exec_server )};	195	delete @dbi_args{qw(on_connect on_error timeout fork_template exec_server)};
284		196
285	my $self = bless \%arg, $class;	197	my $self = bless \%arg, $class;
		198
286	$self->{fh} = $client;	199	$self->{fh} = $client;
287
288	Scalar::Util::weaken (my $wself = $self);
289
290	AnyEvent::Util::fh_nonblocking $client, 1;
291		200
292	my $rbuf;	201	my $rbuf;
293	my @caller = (caller)[1,2]; # the "default" caller	202	my @caller = (caller)[1,2]; # the "default" caller
294		203
295	$self->{rw} = AnyEvent->io (fh => $client, poll => "r", cb => sub {	204	$fork = $fork ? $fork->fork : AnyEvent::Fork->new
296	return unless $wself;	205	or croak "fork: $!";
297	my $len = sysread $client, $rbuf, 65536, length $rbuf;
298	my $err = $!;
299		206
		207	$fork->require ("AnyEvent::DBI::Slave");
		208	$fork->send_arg ($VERSION);
		209	$fork->send_fh ($server);
		210
		211	# we don't rely on the callback, because we use our own
		212	# socketpair, for better or worse.
		213	$fork->run ("AnyEvent::DBI::Slave::serve", sub { });
		214
		215	{
		216	Convert::Scalar::weaken (my $self = $self);
		217
		218	my $cbor = new CBOR::XS;
		219
		220	$self->{rw} = AE::io $client, 0, sub {
		221	my $len = Convert::Scalar::extend_read $client, $rbuf, 65536;
		222
300	if ($len > 0) {	223	if ($len > 0) {
301	# we received data, so reset the timer	224	# we received data, so reset the timer
302	delete $wself->{timer};	225	$self->{last_activity} = AE::now;
303	if ($wself->{timeout}) {
304	$wself->{timer} = AnyEvent->timer (
305	after => $wself->{timeout},
306	cb => sub { $wself && $wself->_timedout },
307	);
308	}
309		226
310	while () {	227	for my $res ($cbor->incr_parse_multiple ($rbuf)) {
311	my $len = unpack "L", $rbuf;
312
313	# full response available?
314	last unless $len && $len + 4 <= length $rbuf;
315
316	my $res = Storable::thaw substr $rbuf, 4;
317	substr $rbuf, 0, $len + 4, ""; # remove length + request
318
319	last unless $wself;	228	last unless $self;
		229
320	my $req = shift @{ $wself->{queue} };	230	my $req = shift @{ $self->{queue} };
321		231
322	if (defined $res->[0]) {	232	if (defined $res->[0]) {
323	$res->[0] = $wself;	233	$res->[0] = $self;
324	$req->[0](@$res);	234	$req->[0](@$res);
325	} else {	235	} else {
326	my $cb = shift @$req;	236	my $cb = shift @$req;
327	$@=$res->[1];	237	local $@ = $res->[1];
328	$cb->();	238	$cb->($self);
329	if ($wself) { # cb() could have deleted it
330	$wself->_error ($res->[1], @$req, $res->[2]); # error, request record, is_fatal	239	$self->_error ($res->[1], @$req, $res->[2]) # error, request record, is_fatal
		240	if $self; # cb() could have deleted it
		241	}
		242
		243	# no more queued requests, so become idle
		244	if ($self && !@{ $self->{queue} }) {
		245	undef $self->{last_activity};
		246	$self->{tw_cb}->();
331	}	247	}
332	}	248	}
333		249
334	# no more queued requests, so cancel timeout	250	} elsif (defined $len) {
335	if ($wself) {	251	# todo, caller?
336	delete $wself->{timer}	252	$self->_error ("unexpected eof", @caller, 1);
337	unless @{ $wself->{queue} };	253	} elsif ($! != Errno::EAGAIN) {
		254	# todo, caller?
		255	$self->_error ("read error: $!", @caller, 1);
		256	}
		257	};
		258
		259	$self->{tw_cb} = sub {
		260	if ($self->{timeout} && $self->{last_activity}) {
		261	if (AE::now > $self->{last_activity} + $self->{timeout}) {
		262	# we did time out
		263	my $req = $self->{queue}[0];
		264	$self->_error (timeout => $req->[1], $req->[2], 1); # timeouts are always fatal
		265	} else {
		266	# we need to re-set the timeout watcher
		267	$self->{tw} = AE::timer
		268	$self->{last_activity} + $self->{timeout} - AE::now,
		269	0,
		270	$self->{tw_cb},
		271	;
338	}	272	}
		273	} else {
		274	# no timeout check wanted, or idle
		275	undef $self->{tw};
339	}	276	}
340
341	} elsif (defined $len) {
342	$wself->_error ("unexpected eof", @caller, 1);
343	} else {
344	return if $err == EAGAIN;
345	$wself->_error ("read error: $err", @caller, 1);
346	}	277	};
347	});
348		278
349	$self->{ww_cb} = sub {	279	$self->{ww_cb} = sub {
350	return unless $wself;	280	$self->{last_activity} = AE::now;
		281
351	my $len = syswrite $client, $wself->{wbuf}	282	my $len = syswrite $client, $self->{wbuf}
352	or return delete $wself->{ww};	283	or return delete $self->{ww};
353		284
354	substr $wself->{wbuf}, 0, $len, "";	285	substr $self->{wbuf}, 0, $len, "";
355	};
356
357	my $pid = fork;
358
359	if ($pid) {
360	# parent
361	close $server;
362	} elsif (defined $pid) {
363	# child
364	my $serv_fno = fileno $server;
365
366	if ($self->{exec_server}) {
367	fcntl $server, F_SETFD, 0; # don't close the server side
368	exec "$^X -MAnyEvent::DBI -e AnyEvent::DBI::start_server $serv_fno";
369	POSIX::_exit 124;
370	} else {
371	($_ != $serv_fno) && POSIX::close $_
372	for $^F+1..$fd_max;
373	serve $serv_fno;
374	POSIX::_exit 0; # not reachable
375	}	286	};
376	} else {
377	croak "fork: $!";
378	}	287	}
379		288
380	$self->{child_pid} = $pid;
381	# set a connect timeout
382	if ($self->{timeout}) {
383	$self->{timer} = AnyEvent->timer (
384	after => $self->{timeout},
385	cb => sub { $wself && $wself->_timedout },
386	);
387	}
388	$self->_req (	289	$self->_req (
		290	sub {
		291	return unless $self;
		292	$self->{child_pid} = $_[1];
		293	},
		294	(caller)[1,2],
		295	"req_pid"
		296	);
		297
		298	$self->_req (
		299	sub {
		300	return unless $self;
389	($self->{on_connect} ? $self->{on_connect} : sub { }),	301	&{ $self->{on_connect} } if $self->{on_connect};
		302	},
390	(caller)[1,2],	303	(caller)[1,2],
391	req_open => $dbi, $user, $pass, %dbi_args	304	req_open => $dbi, $user, $pass, %dbi_args
392	);	305	);
393		306
394	$self	307	$self
…		…
397	sub _server_pid {	310	sub _server_pid {
398	shift->{child_pid}	311	shift->{child_pid}
399	}	312	}
400		313
401	sub kill_child {	314	sub kill_child {
402	my $self = shift;	315	my $self = shift;
		316
403	my $child_pid = delete $self->{child_pid};	317	if (my $pid = delete $self->{child_pid}) {
404	if ($child_pid) {
405	# send SIGKILL in two seconds
406	my $murder_timer = AnyEvent->timer (
407	after => 2,
408	cb => sub {
409	kill 9, $child_pid;
410	},
411	);
412
413	# reap process	318	# kill and reap process
414	my $kid_watcher;	319	my $kid_watcher; $kid_watcher = AE::child $pid, sub {
415	$kid_watcher = AnyEvent->child (
416	pid => $child_pid ,
417	cb => sub {
418	# just hold on to this so it won't go away
419	undef $kid_watcher;	320	undef $kid_watcher;
420	# cancel SIGKILL
421	undef $murder_timer;
422	},
423	);	321	};
424
425	# SIGTERM = the beginning of the end
426	kill TERM => $child_pid;	322	kill TERM => $pid;
427	}	323	}
		324
		325	delete $self->{rw};
		326	delete $self->{ww};
		327	delete $self->{tw};
		328	close delete $self->{fh};
428	}	329	}
429		330
430	sub DESTROY {	331	sub DESTROY {
431	shift->kill_child;	332	shift->kill_child;
432	}	333	}
433		334
434	sub _error {	335	sub _error {
435	my ($self, $error, $filename, $line, $fatal) = @_;	336	my ($self, $error, $filename, $line, $fatal) = @_;
436		337
437	if ($fatal) {	338	if ($fatal) {
		339	delete $self->{tw};
438	delete $self->{rw};	340	delete $self->{rw};
439	delete $self->{ww};	341	delete $self->{ww};
440	delete $self->{fh};	342	delete $self->{fh};
441	delete $self->{timer};
442		343
443	# for fatal errors call all enqueued callbacks with error	344	# for fatal errors call all enqueued callbacks with error
444	while (my $req = shift @{$self->{queue}}) {	345	while (my $req = shift @{$self->{queue}}) {
445	$@ = $error;	346	local $@ = $error;
446	$req->[0]->();	347	$req->[0]->($self);
447	}	348	}
448	$self->kill_child;	349	$self->kill_child;
449	}	350	}
450		351
451	$@ = $error;	352	local $@ = $error;
452		353
453	if ($self->{on_error}) {	354	if ($self->{on_error}) {
454	$self->{on_error}($self, $filename, $line, $fatal)	355	$self->{on_error}($self, $filename, $line, $fatal)
455	} else {	356	} else {
456	die "$error at $filename, line $line\n";	357	die "$error at $filename, line $line\n";
457	}	358	}
458	}	359	}
459		360
460	=item $dbh->on_error ($cb->($dbh, $filename, $line, $fatal))	361	=item $dbh->on_error ($cb->($dbh, $filename, $line, $fatal))
461		362
462	Sets (or clears, with C<undef>) the on_error handler.	363	Sets (or clears, with C<undef>) the C<on_error> handler.
463		364
464	=cut	365	=cut
465		366
466	sub on_error {	367	sub on_error {
467	$_[0]{on_error} = $_[1];	368	$_[0]{on_error} = $_[1];
468	}	369	}
469		370
470	=item $dbh->on_connect ($cb->($dbh))
471
472	Sets (or clears, with C<undef>) the on_connect handler.
473
474	=cut
475
476	sub on_connect {
477	$_[0]{on_connect} = $_[1];
478	}
479
480	=item $dbh->timeout ($seconds)	371	=item $dbh->timeout ($seconds)
481		372
482	Sets (or clears, with C<undef>) the database timeout. Useful to extend the	373	Sets (or clears, with C<undef>) the database timeout. Useful to extend the
483	timeout when you are about to make a really long query.	374	timeout when you are about to make a really long query.
484		375
485	=cut	376	=cut
486		377
487	sub timeout {	378	sub timeout {
488	my ($self, $timeout) = @_;	379	my ($self, $timeout) = @_;
489		380
490	if ($timeout) {
491	$self->{timeout} = $timeout;	381	$self->{timeout} = $timeout;
		382
492	# reschedule timer if one was running	383	# reschedule timer if one was running
493	if ($self->{timer}) {	384	$self->{tw_cb}->();
494	Scalar::Util::weaken (my $wself = $self);
495	$self->{timer} = AnyEvent->timer (
496	after => $self->{timeout},
497	cb => sub { $wself && $wself->_timedout },
498	);
499	}
500	} else {
501	delete @{%$self}[qw(timer timeout)];
502	}
503	}
504
505	sub _timedout {
506	my ($self) = @_;
507
508	my $req = shift @{ $self->{queue} };
509
510	if ($req) {
511	my $cb = shift @$req;
512	$@ = 'TIMEOUT';
513	$cb->();
514	$self->_error ('TIMEOUT', @$req, 1); # timeouts are always fatal
515	} else {
516	# shouldn't be possible to timeout without a pending request
517	$self->_error ('TIMEOUT', 'NO_PENDING_WTF', 0, 1);
518	}
519	}	385	}
520		386
521	sub _req {	387	sub _req {
522	my ($self, $cb, $filename, $line) = splice @_, 0, 4, ();	388	my ($self, $cb, $filename, $line) = splice @_, 0, 4, ();
523		389
524	if (!$self->{fh}) {	390	unless ($self->{fh}) {
525	my $err = $@ = 'NO DATABASE CONNECTION';	391	local $@ = my $err = 'no database connection';
526	$cb->();	392	$cb->($self);
527	$self->_error ($err, $filename, $line, 1);	393	$self->_error ($err, $filename, $line, 1);
528	return;	394	return;
529	}	395	}
530		396
531	push @{ $self->{queue} }, [$cb, $filename, $line ];	397	push @{ $self->{queue} }, [$cb, $filename, $line];
532		398
		399	# re-start timeout if necessary
533	if ($self->{timeout} && !$self->{timer}) {	400	if ($self->{timeout} && !$self->{tw}) {
534	Scalar::Util::weaken (my $wself = $self);	401	$self->{last_activity} = AE::now;
535	$self->{timer} = AnyEvent->timer (	402	$self->{tw_cb}->();
536	after => $self->{timeout},
537	cb => sub { $wself && $wself->_timedout },
538	);
539	}	403	}
540		404
541	$self->{wbuf} .= pack "L/a*", Storable::freeze \@_;	405	$self->{wbuf} .= CBOR::XS::encode_cbor \@_;
542		406
543	unless ($self->{ww}) {	407	unless ($self->{ww}) {
544	my $len = syswrite $self->{fh}, $self->{wbuf};	408	my $len = syswrite $self->{fh}, $self->{wbuf};
545	substr $self->{wbuf}, 0, $len, "";	409	substr $self->{wbuf}, 0, $len, "";
546		410
547	# still any left? then install a write watcher	411	# still any left? then install a write watcher
548	$self->{ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $self->{ww_cb})	412	$self->{ww} = AE::io $self->{fh}, 1, $self->{ww_cb}
549	if length $self->{wbuf};	413	if length $self->{wbuf};
550	}	414	}
551	}	415	}
552		416
		417	=item $dbh->attr ($attr_name[, $attr_value], $cb->($dbh, $new_value))
		418
		419	An accessor for the database handle attributes, such as C<AutoCommit>,
		420	C<RaiseError>, C<PrintError> and so on. If you provide an C<$attr_value>
		421	(which might be C<undef>), then the given attribute will be set to that
		422	value.
		423
		424	The callback will be passed the database handle and the attribute's value
		425	if successful.
		426
		427	If an error occurs and the C<on_error> callback returns, then only C<$dbh>
		428	will be passed and C<$@> contains the error message.
		429
553	=item $dbh->exec ("statement", @args, $cb->($dbh, \@rows, \%metadata))	430	=item $dbh->exec ("statement", @args, $cb->($dbh, \@rows, $rv))
554		431
555	Executes the given SQL statement with placeholders replaced by	432	Executes the given SQL statement with placeholders replaced by
556	C<@args>. The statement will be prepared and cached on the server side, so	433	C<@args>. The statement will be prepared and cached on the server side, so
557	using placeholders is compulsory.	434	using placeholders is extremely important.
558		435
559	The callback will be called with a weakened AnyEvent::DBI object as the first	436	The callback will be called with a weakened AnyEvent::DBI object as the
560	argument and the result of C<fetchall_arrayref> as (or C<undef> if the	437	first argument and the result of C<fetchall_arrayref> as (or C<undef>
561	statement wasn't a select statement) as the second argument. Third argument is	438	if the statement wasn't a select statement) as the second argument.
562	a hash reference holding metadata about the request. Currently, the only key
563	defined is C<$metadata->{rv}> holding the return value of
564	C<execute>. Additional metadata might be added.
565		439
		440	Third argument is the return value from the C<< DBI->execute >> method
		441	call.
		442
566	If an error occurs and the C<on_error> callback returns, then no arguments	443	If an error occurs and the C<on_error> callback returns, then only C<$dbh>
567	will be passed and C<$@> contains the error message.	444	will be passed and C<$@> contains the error message.
568		445
569	=item $dbh->attr (attr_name, [ $attr_value ], $cb->($dbh, $new_value))	446	=item $dbh->stattr ($attr_name, $cb->($dbh, $value))
570		447
571	An accessor for the handle attributes, such as AutoCommit, RaiseError,	448	An accessor for the statement attributes of the most recently executed
572	PrintError, etc. If you provide an $attr_value, then the given attribute will	449	statement, such as C<NAME> or C<TYPE>.
573	be set to that value.
574		450
575	The callback will be passed the database handle and the	451	The callback will be passed the database handle and the attribute's value
576	attribute's value if successful. If accessing the attribute fails, then no	452	if successful.
577	arguments are passed to your callback, and $@ contains a description of the
578	problem instead.
579		453
		454	If an error occurs and the C<on_error> callback returns, then only C<$dbh>
		455	will be passed and C<$@> contains the error message.
		456
580	=item $dbh->begin_work ($cb->($dbh))	457	=item $dbh->begin_work ($cb->($dbh[, $rc]))
581		458
582	=item $dbh->commit ($cb->($dbh))	459	=item $dbh->commit ($cb->($dbh[, $rc]))
583		460
584	=item $dbh->rollback ($cb->($dbh))	461	=item $dbh->rollback ($cb->($dbh[, $rc]))
585		462
586	The begin_work, commit, and rollback methods exopose the equivelant transaction	463	The begin_work, commit, and rollback methods expose the equivalent
587	control methods of the DBI. If something goes wrong, you will get no $dbh in	464	transaction control method of the DBI driver. On success, C<$rc> is true.
588	your callaback, and will instead have an error to examine in $@.
589		465
		466	If an error occurs and the C<on_error> callback returns, then only C<$dbh>
		467	will be passed and C<$@> contains the error message.
		468
590	=item $dbh->func ('string_which_yields_args_when_evaled', $func_name, $cb->($dbh, $result, $handle_error))	469	=item $dbh->func ('string_which_yields_args_when_evaled', $func_name, $cb->($dbh, $rc, $dbi_err, $dbi_errstr))
591		470
592	This gives access to database driver private methods. Because they are not	471	This gives access to database driver private methods. Because they
593	standard you cannot always depend on the value of $result or $handle_error.	472	are not standard you cannot always depend on the value of C<$rc> or
594	Check the documentation for your specific driver/function combination to see	473	C<$dbi_err>. Check the documentation for your specific driver/function
595	what it returns.	474	combination to see what it returns.
596		475
597	Note that the first argument will be eval'ed to produce the argument list to	476	Note that the first argument will be eval'ed to produce the argument list to
598	the func() method. This must be done because the searialization protocol	477	the func() method. This must be done because the serialization protocol
599	between the AnyEvent::DBI server process and your program does not support the	478	between the AnyEvent::DBI server process and your program does not support the
600	passage of closures.	479	passage of closures.
601		480
602	Here's an example to extend the query language in SQLite so it supports an	481	Here's an example to extend the query language in SQLite so it supports an
603	intstr() function:	482	intstr() function:
604		483
605	$cv = AnyEvent->condvar;	484	$cv = AnyEvent->condvar;
606	$dbh->func(	485	$dbh->func (
607	q{	486	q{
608	'instr',	487	instr => 2, sub {
609	2,
610	sub {
611	my ($string, $search) = @_;	488	my ($string, $search) = @_;
612	return index $string, $search;	489	return index $string, $search;
613	},	490	},
614	},	491	},
615	'create_function',	492	create_function => sub {
616	sub {return $cv->send($@) unless $_[0];$cv->send(undef,@_[1,2]);}	493	return $cv->send ($@)
		494	unless $#_;
		495	$cv->send (undef, @_[1,2,3]);
		496	}
617	);	497	);
618	my ($err,$result,$handle_err) = $cv->recv();	498
		499	my ($err,$rc,$errcode,$errstr) = $cv->recv;
		500
		501	die $err if defined $err;
619	die "EVAL failed: $err" if $err;	502	die "EVAL failed: $errstr"
		503	if $errcode;
		504
620	# otherwise, we can ignore $result and $handle_err for this particular func	505	# otherwise, we can ignore $rc and $errcode for this particular func
621		506
622	=cut	507	=cut
623		508
624	for my $cmd_name (qw(exec attr begin_work commit rollback func)) {	509	for my $cmd_name (qw(attr exec stattr begin_work commit rollback func)) {
625	eval 'sub ' . $cmd_name . '{	510	eval 'sub ' . $cmd_name . '{
626	my $cb = pop;	511	my $cb = pop;
627	splice @_, 1, 0, $cb, (caller)[1,2], "req_' . $cmd_name . '";	512	splice @_, 1, 0, $cb, (caller)[1,2], "req_' . $cmd_name . '";
628	goto &_req;	513	&_req
629	}';	514	}';
630	}	515	}
631		516
632	=back	517	=back
633		518
634	=head1 SEE ALSO	519	=head1 SEE ALSO
635		520
636	L<AnyEvent>, L<DBI>.	521	L<AnyEvent>, L<DBI>, L<Coro::Mysql>.
637		522
638	=head1 AUTHOR	523	=head1 AUTHOR AND CONTACT
639		524
640	Marc Lehmann <schmorp@schmorp.de>	525	Marc Lehmann <schmorp@schmorp.de> (current maintainer)
641	http://home.schmorp.de/	526	http://home.schmorp.de/
642		527
643	Adam Rosenstein <adam@redcondor.com>	528	Adam Rosenstein <adam@redcondor.com>
644	http://www.redcondor.com/	529	http://www.redcondor.com/
645		530
646	=cut	531	=cut
647		532
648	1;	533	1
649

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Comparing AnyEvent-DBI/DBI.pm (file contents): Revision 1.10 by root, Tue Jun 2 16:16:03 2009 UTC vs. Revision 1.18 by root, Sun Aug 27 09:54:25 2017 UTC

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Comparing AnyEvent-DBI/DBI.pm (file contents):
Revision 1.10 by root, Tue Jun 2 16:16:03 2009 UTC vs.
Revision 1.18 by root, Sun Aug 27 09:54:25 2017 UTC