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Overhauled "lock" functionality

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This commit is contained in:
Michael 2017-06-04 07:26:21 +00:00
parent ec5a3c3440
commit 32f61016d3
3 changed files with 63 additions and 81 deletions
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2
include/dbstructure.php
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@ -1205,7 +1205,7 @@ function db_definition() {
"id" => array("type" => "int(11)", "not null" => "1", "extra" => "auto_increment", "primary" => "1"), "id" => array("type" => "int(11)", "not null" => "1", "extra" => "auto_increment", "primary" => "1"),
"name" => array("type" => "varchar(128)", "not null" => "1", "default" => ""), "name" => array("type" => "varchar(128)", "not null" => "1", "default" => ""),
"locked" => array("type" => "tinyint(1)", "not null" => "1", "default" => "0"), "locked" => array("type" => "tinyint(1)", "not null" => "1", "default" => "0"),
"created" => array("type" => "datetime", "default" => NULL_DATE), "pid" => array("type" => "int(10) unsigned", "not null" => "1", "default" => "0"),
), ),
"indexes" => array( "indexes" => array(
"PRIMARY" => array("id"), "PRIMARY" => array("id"),

80
include/lock.php
View file

@ -1,80 +0,0 @@
<?php
// Provide some ability to lock a PHP function so that multiple processes
// can't run the function concurrently
if (! function_exists('lock_function')) {
function lock_function($fn_name, $block = true, $wait_sec = 2, $timeout = 30) {
if ( $wait_sec == 0 )
$wait_sec = 2; // don't let the user pick a value that's likely to crash the system
$got_lock = false;
$start = time();
do {
q("LOCK TABLE `locks` WRITE");
$r = q("SELECT `locked`, `created` FROM `locks` WHERE `name` = '%s' LIMIT 1",
dbesc($fn_name)
);
if ((dbm::is_result($r)) AND (!$r[0]['locked'] OR (strtotime($r[0]['created']) < time() - 3600))) {
q("UPDATE `locks` SET `locked` = 1, `created` = '%s' WHERE `name` = '%s'",
dbesc(datetime_convert()),
dbesc($fn_name)
);
$got_lock = true;
}
elseif (! dbm::is_result($r)) {
/// @TODO the Boolean value for count($r) should be equivalent to the Boolean value of $r
q("INSERT INTO `locks` (`name`, `created`, `locked`) VALUES ('%s', '%s', 1)",
dbesc($fn_name),
dbesc(datetime_convert())
);
$got_lock = true;
}
q("UNLOCK TABLES");
if (($block) && (! $got_lock))
sleep($wait_sec);
} while (($block) && (! $got_lock) && ((time() - $start) < $timeout));
logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock . ' time = ' . (time() - $start), LOGGER_DEBUG);
return $got_lock;
}}
if (! function_exists('block_on_function_lock')) {
function block_on_function_lock($fn_name, $wait_sec = 2, $timeout = 30) {
if ( $wait_sec == 0 )
$wait_sec = 2; // don't let the user pick a value that's likely to crash the system
$start = time();
do {
$r = q("SELECT locked FROM locks WHERE name = '%s' LIMIT 1",
dbesc($fn_name)
);
if (dbm::is_result($r) && $r[0]['locked']) {
sleep($wait_sec);
}
} while (dbm::is_result($r) && $r[0]['locked'] && ((time() - $start) < $timeout));
return;
}}
if (! function_exists('unlock_function')) {
function unlock_function($fn_name) {
$r = q("UPDATE `locks` SET `locked` = 0, `created` = '%s' WHERE `name` = '%s'",
dbesc(NULL_DATE),
dbesc($fn_name)
);
logger('unlock_function: released lock for function ' . $fn_name, LOGGER_DEBUG);
return;
}}

62
src/Util/Lock.php Normal file
View file

@ -0,0 +1,62 @@
<?php
namespace Friendica\Util;
/**
* @file src/Util/Lock.php
* @brief Functions for preventing parallel execution of functions
*
*/
use dba;
use dbm;
/**
* @brief This class contain Functions for preventing parallel execution of functions
*/
class Lock {
// Provide some ability to lock a PHP function so that multiple processes
// can't run the function concurrently
public static function set($fn_name, $wait_sec = 2, $timeout = 30) {
if ($wait_sec == 0) {
$wait_sec = 2;
}
$got_lock = false;
$start = time();
do {
dba:p("LOCK TABLE `locks` WRITE");
$lock = dba::select('locks', array('locked'), array('name' => $fn_name), array('limit' => 1));
if ((dbm::is_result($lock)) AND !$lock['locked']) {
dba::update('locks', array('locked' => true), array('name' => $fn_name));
$got_lock = true;
} elseif (!dbm::is_result($lock)) {
dbm::insert('locks', array('name' => $fn_name, 'locked' => true));
$got_lock = true;
}
dbm::p("UNLOCK TABLES");
if (!$got_lock) {
sleep($wait_sec);
}
} while (!$got_lock AND ((time() - $start) < $timeout));
logger('lock_function: function ' . $fn_name . ' with blocking = ' . $block . ' got_lock = ' . $got_lock . ' time = ' . (time() - $start), LOGGER_DEBUG);
return $got_lock;
}
public static function remove($fn_name) {
dba::update('locks', array('locked' => false), array('name' => $fn_name));
logger('unlock_function: released lock for function ' . $fn_name, LOGGER_DEBUG);
return;
}
}