1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
|
<?php
/**
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
namespace Wikimedia\Rdbms;
use InvalidArgumentException;
/**
* LoadBalancer manager for sites with one "main" cluster and any number of "external" clusters
*
* @see LBFactoryMulti
*
* The class allows for large site farms to split up their data in the following ways:
* - Vertically shard compact site-specific data by site (e.g. page/comment metadata)
* - Vertically shard compact global data by module (e.g. account/notification data)
* - Horizontally shard any bulk data by blob key (e.g. page/comment content)
*
* @ingroup Database
*/
class LBFactorySimple extends LBFactory {
/** @var LoadBalancer */
private $mainLB;
/** @var LoadBalancer[] */
private $externalLBs = [];
/** @var array Configuration for the LoadMonitor to use within LoadBalancer instances */
private $loadMonitorConfig;
/** @var array[] Map of (server index => server config map) */
private $mainServers;
/** @var array[][] Map of (cluster => server index => server config map) */
private $externalServersByCluster = [];
/**
* @see LBFactory::__construct()
* @param array $conf Additional parameters include:
* - servers : list of server config maps to Database::factory().
* Additionally, the server maps should have a 'load' key, which is used to decide
* how often clients connect to one server verses the others. A 'max lag' key should
* also be set on server maps, indicating how stale the data can be before the load
* balancer tries to avoid using it. The map can have 'is static' set to disable blocking
* replication sync checks (intended for archive servers with unchanging data).
* - externalClusters : map of cluster names to server arrays. The servers arrays have the
* same format as "servers" above.
* - loadMonitor: LoadMonitor::__construct() parameters with "class" field. [optional]
*/
public function __construct( array $conf ) {
parent::__construct( $conf );
$this->mainServers = $conf['servers'] ?? [];
foreach ( ( $conf['externalClusters'] ?? [] ) as $cluster => $servers ) {
foreach ( $servers as $index => $server ) {
$this->externalServersByCluster[$cluster][$index] = $server;
}
}
if ( isset( $conf['loadMonitor'] ) ) {
$this->loadMonitorConfig = $conf['loadMonitor'];
} elseif ( isset( $conf['loadMonitorClass'] ) ) { // b/c
$this->loadMonitorConfig = [ 'class' => $conf['loadMonitorClass'] ];
} else {
$this->loadMonitorConfig = [ 'class' => LoadMonitor::class ];
}
}
public function newMainLB( $domain = false ): ILoadBalancerForOwner {
return $this->newLoadBalancer(
self::CLUSTER_MAIN_DEFAULT,
$this->mainServers
);
}
public function getMainLB( $domain = false ): ILoadBalancer {
$this->mainLB ??= $this->newMainLB( $domain );
return $this->mainLB;
}
public function newExternalLB( $cluster ): ILoadBalancerForOwner {
if ( !isset( $this->externalServersByCluster[$cluster] ) ) {
throw new InvalidArgumentException( "Unknown cluster '$cluster'." );
}
return $this->newLoadBalancer(
$cluster,
$this->externalServersByCluster[$cluster]
);
}
public function getExternalLB( $cluster ): ILoadBalancer {
if ( !isset( $this->externalLBs[$cluster] ) ) {
$this->externalLBs[$cluster] = $this->newExternalLB( $cluster );
}
return $this->externalLBs[$cluster];
}
public function getAllMainLBs(): array {
return [ self::CLUSTER_MAIN_DEFAULT => $this->getMainLB() ];
}
public function getAllExternalLBs(): array {
$lbs = [];
foreach ( $this->externalServersByCluster as $cluster => $_ ) {
$lbs[$cluster] = $this->getExternalLB( $cluster );
}
return $lbs;
}
private function newLoadBalancer( string $clusterName, array $servers ) {
$lb = new LoadBalancer( array_merge(
$this->baseLoadBalancerParams(),
[
'servers' => $servers,
'loadMonitor' => $this->loadMonitorConfig,
'clusterName' => $clusterName
]
) );
$this->initLoadBalancer( $lb );
return $lb;
}
protected function getLBsForOwner() {
if ( $this->mainLB !== null ) {
yield $this->mainLB;
}
foreach ( $this->externalLBs as $lb ) {
yield $lb;
}
}
}
|
