includes/SquidPurgeClient.php

   1 <?php
   2 /**
   3  * Squid and Varnish cache purging.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 /**
  24  * An HTTP 1.0 client built for the purposes of purging Squid and Varnish.
  25  * Uses asynchronous I/O, allowing purges to be done in a highly parallel
  26  * manner.
  27  *
  28  * Could be replaced by curl_multi_exec() or some such.
  29  */
  30 class SquidPurgeClient {
  31         var $host, $port, $ip;
  32
  33         var $readState = 'idle';
  34         var $writeBuffer = '';
  35         var $requests = array();
  36         var $currentRequestIndex;
  37
  38         const EINTR = 4;
  39         const EAGAIN = 11;
  40         const EINPROGRESS = 115;
  41         const BUFFER_SIZE = 8192;
  42
  43         /**
  44          * The socket resource, or null for unconnected, or false for disabled due to error
  45          */
  46         var $socket;
  47
  48         var $readBuffer;
  49
  50         var $bodyRemaining;
  51
  52         /**
  53          * @param $server string
  54          * @param $options array
  55          */
  56         public function __construct( $server, $options = array() ) {
  57                 $parts = explode( ':', $server, 2 );
  58                 $this->host = $parts[0];
  59                 $this->port = isset( $parts[1] ) ? $parts[1] : 80;
  60         }
  61
  62         /**
  63          * Open a socket if there isn't one open already, return it.
  64          * Returns false on error.
  65          *
  66          * @return bool|resource
  67          */
  68         protected function getSocket() {
  69                 if ( $this->socket !== null ) {
  70                         return $this->socket;
  71                 }
  72
  73                 $ip = $this->getIP();
  74                 if ( !$ip ) {
  75                         $this->log( "DNS error" );
  76                         $this->markDown();
  77                         return false;
  78                 }
  79                 $this->socket = socket_create( AF_INET, SOCK_STREAM, SOL_TCP );
  80                 socket_set_nonblock( $this->socket );
  81                 wfSuppressWarnings();
  82                 $ok = socket_connect( $this->socket, $ip, $this->port );
  83                 wfRestoreWarnings();
  84                 if ( !$ok ) {
  85                         $error = socket_last_error( $this->socket );
  86                         if ( $error !== self::EINPROGRESS ) {
  87                                 $this->log( "connection error: " . socket_strerror( $error ) );
  88                                 $this->markDown();
  89                                 return false;
  90                         }
  91                 }
  92
  93                 return $this->socket;
  94         }
  95
  96         /**
  97          * Get read socket array for select()
  98          * @return array
  99          */
 100         public function getReadSocketsForSelect() {
 101                 if ( $this->readState == 'idle' ) {
 102                         return array();
 103                 }
 104                 $socket = $this->getSocket();
 105                 if ( $socket === false ) {
 106                         return array();
 107                 }
 108                 return array( $socket );
 109         }
 110
 111         /**
 112          * Get write socket array for select()
 113          * @return array
 114          */
 115         public function getWriteSocketsForSelect() {
 116                 if ( !strlen( $this->writeBuffer ) ) {
 117                         return array();
 118                 }
 119                 $socket = $this->getSocket();
 120                 if ( $socket === false ) {
 121                         return array();
 122                 }
 123                 return array( $socket );
 124         }
 125
 126         /**
 127          * Get the host's IP address.
 128          * Does not support IPv6 at present due to the lack of a convenient interface in PHP.
 129          */
 130         protected function getIP() {
 131                 if ( $this->ip === null ) {
 132                         if ( IP::isIPv4( $this->host ) ) {
 133                                 $this->ip = $this->host;
 134                         } elseif ( IP::isIPv6( $this->host ) ) {
 135                                 throw new MWException( '$wgSquidServers does not support IPv6' );
 136                         } else {
 137                                 wfSuppressWarnings();
 138                                 $this->ip = gethostbyname( $this->host );
 139                                 if ( $this->ip === $this->host ) {
 140                                         $this->ip = false;
 141                                 }
 142                                 wfRestoreWarnings();
 143                         }
 144                 }
 145                 return $this->ip;
 146         }
 147
 148         /**
 149          * Close the socket and ignore any future purge requests.
 150          * This is called if there is a protocol error.
 151          */
 152         protected function markDown() {
 153                 $this->close();
 154                 $this->socket = false;
 155         }
 156
 157         /**
 158          * Close the socket but allow it to be reopened for future purge requests
 159          */
 160         public function close() {
 161                 if ( $this->socket ) {
 162                         wfSuppressWarnings();
 163                         socket_set_block( $this->socket );
 164                         socket_shutdown( $this->socket );
 165                         socket_close( $this->socket );
 166                         wfRestoreWarnings();
 167                 }
 168                 $this->socket = null;
 169                 $this->readBuffer = '';
 170                 // Write buffer is kept since it may contain a request for the next socket
 171         }
 172
 173         /**
 174          * Queue a purge operation
 175          *
 176          * @param $url string
 177          */
 178         public function queuePurge( $url ) {
 179                 $url = SquidUpdate::expand( str_replace( "\n", '', $url ) );
 180                 $this->requests[] = "PURGE $url HTTP/1.0\r\n" .
 181                         "Connection: Keep-Alive\r\n" .
 182                         "Proxy-Connection: Keep-Alive\r\n" .
 183                         "User-Agent: " . Http::userAgent() . ' ' . __CLASS__ . "\r\n\r\n";
 184                 if ( $this->currentRequestIndex === null ) {
 185                         $this->nextRequest();
 186                 }
 187         }
 188
 189         /**
 190          * @return bool
 191          */
 192         public function isIdle() {
 193                 return strlen( $this->writeBuffer ) == 0 && $this->readState == 'idle';
 194         }
 195
 196         /**
 197          * Perform pending writes. Call this when socket_select() indicates that writing will not block.
 198          */
 199         public function doWrites() {
 200                 if ( !strlen( $this->writeBuffer ) ) {
 201                         return;
 202                 }
 203                 $socket = $this->getSocket();
 204                 if ( !$socket ) {
 205                         return;
 206                 }
 207
 208                 if ( strlen( $this->writeBuffer ) <= self::BUFFER_SIZE ) {
 209                         $buf = $this->writeBuffer;
 210                         $flags = MSG_EOR;
 211                 } else {
 212                         $buf = substr( $this->writeBuffer, 0, self::BUFFER_SIZE );
 213                         $flags = 0;
 214                 }
 215                 wfSuppressWarnings();
 216                 $bytesSent = socket_send( $socket, $buf, strlen( $buf ), $flags );
 217                 wfRestoreWarnings();
 218
 219                 if ( $bytesSent === false ) {
 220                         $error = socket_last_error( $socket );
 221                         if ( $error != self::EAGAIN && $error != self::EINTR ) {
 222                                 $this->log( 'write error: ' . socket_strerror( $error ) );
 223                                 $this->markDown();
 224                         }
 225                         return;
 226                 }
 227
 228                 $this->writeBuffer = substr( $this->writeBuffer, $bytesSent );
 229         }
 230
 231         /**
 232          * Read some data. Call this when socket_select() indicates that the read buffer is non-empty.
 233          */
 234         public function doReads() {
 235                 $socket = $this->getSocket();
 236                 if ( !$socket ) {
 237                         return;
 238                 }
 239
 240                 $buf = '';
 241                 wfSuppressWarnings();
 242                 $bytesRead = socket_recv( $socket, $buf, self::BUFFER_SIZE, 0 );
 243                 wfRestoreWarnings();
 244                 if ( $bytesRead === false ) {
 245                         $error = socket_last_error( $socket );
 246                         if ( $error != self::EAGAIN && $error != self::EINTR ) {
 247                                 $this->log( 'read error: ' . socket_strerror( $error ) );
 248                                 $this->markDown();
 249                                 return;
 250                         }
 251                 } elseif ( $bytesRead === 0 ) {
 252                         // Assume EOF
 253                         $this->close();
 254                         return;
 255                 }
 256
 257                 $this->readBuffer .= $buf;
 258                 while ( $this->socket && $this->processReadBuffer() === 'continue' );
 259         }
 260
 261         /**
 262          * @throws MWException
 263          * @return string
 264          */
 265         protected function processReadBuffer() {
 266                 switch ( $this->readState ) {
 267                 case 'idle':
 268                         return 'done';
 269                 case 'status':
 270                 case 'header':
 271                         $lines = explode( "\r\n", $this->readBuffer, 2 );
 272                         if ( count( $lines ) < 2 ) {
 273                                 return 'done';
 274                         }
 275                         if ( $this->readState == 'status' )  {
 276                                 $this->processStatusLine( $lines[0] );
 277                         } else { // header
 278                                 $this->processHeaderLine( $lines[0] );
 279                         }
 280                         $this->readBuffer = $lines[1];
 281                         return 'continue';
 282                 case 'body':
 283                         if ( $this->bodyRemaining !== null ) {
 284                                 if ( $this->bodyRemaining > strlen( $this->readBuffer ) ) {
 285                                         $this->bodyRemaining -= strlen( $this->readBuffer );
 286                                         $this->readBuffer = '';
 287                                         return 'done';
 288                                 } else {
 289                                         $this->readBuffer = substr( $this->readBuffer, $this->bodyRemaining );
 290                                         $this->bodyRemaining = 0;
 291                                         $this->nextRequest();
 292                                         return 'continue';
 293                                 }
 294                         } else {
 295                                 // No content length, read all data to EOF
 296                                 $this->readBuffer = '';
 297                                 return 'done';
 298                         }
 299                 default:
 300                         throw new MWException( __METHOD__.': unexpected state' );
 301                 }
 302         }
 303
 304         /**
 305          * @param $line
 306          * @return
 307          */
 308         protected function processStatusLine( $line ) {
 309                 if ( !preg_match( '!^HTTP/(\d+)\.(\d+) (\d{3}) (.*)$!', $line, $m ) ) {
 310                         $this->log( 'invalid status line' );
 311                         $this->markDown();
 312                         return;
 313                 }
 314                 list( , , , $status, $reason ) = $m;
 315                 $status = intval( $status );
 316                 if ( $status !== 200 && $status !== 404 ) {
 317                         $this->log( "unexpected status code: $status $reason" );
 318                         $this->markDown();
 319                         return;
 320                 }
 321                 $this->readState = 'header';
 322         }
 323
 324         /**
 325          * @param $line string
 326          */
 327         protected function processHeaderLine( $line ) {
 328                 if ( preg_match( '/^Content-Length: (\d+)$/i', $line, $m ) ) {
 329                         $this->bodyRemaining = intval( $m[1] );
 330                 } elseif ( $line === '' ) {
 331                         $this->readState = 'body';
 332                 }
 333         }
 334
 335         protected function nextRequest() {
 336                 if ( $this->currentRequestIndex !== null ) {
 337                         unset( $this->requests[$this->currentRequestIndex] );
 338                 }
 339                 if ( count( $this->requests ) ) {
 340                         $this->readState = 'status';
 341                         $this->currentRequestIndex = key( $this->requests );
 342                         $this->writeBuffer = $this->requests[$this->currentRequestIndex];
 343                 } else {
 344                         $this->readState = 'idle';
 345                         $this->currentRequestIndex = null;
 346                         $this->writeBuffer = '';
 347                 }
 348                 $this->bodyRemaining = null;
 349         }
 350
 351         /**
 352          * @param $msg string
 353          */
 354         protected function log( $msg ) {
 355                 wfDebugLog( 'squid', __CLASS__." ($this->host): $msg\n" );
 356         }
 357 }
 358
 359 class SquidPurgeClientPool {
 360
 361         /**
 362          * @var array of SquidPurgeClient
 363          */
 364         var $clients = array();
 365         var $timeout = 5;
 366
 367         /**
 368          * @param $options array
 369          */
 370         function __construct( $options = array() ) {
 371                 if ( isset( $options['timeout'] ) ) {
 372                         $this->timeout = $options['timeout'];
 373                 }
 374         }
 375
 376         /**
 377          * @param $client SquidPurgeClient
 378          * @return void
 379          */
 380         public function addClient( $client ) {
 381                 $this->clients[] = $client;
 382         }
 383
 384         public function run() {
 385                 $done = false;
 386                 $startTime = microtime( true );
 387                 while ( !$done ) {
 388                         $readSockets = $writeSockets = array();
 389                         /**
 390                          * @var $client SquidPurgeClient
 391                          */
 392                         foreach ( $this->clients as $clientIndex => $client ) {
 393                                 $sockets = $client->getReadSocketsForSelect();
 394                                 foreach ( $sockets as $i => $socket ) {
 395                                         $readSockets["$clientIndex/$i"] = $socket;
 396                                 }
 397                                 $sockets = $client->getWriteSocketsForSelect();
 398                                 foreach ( $sockets as $i => $socket ) {
 399                                         $writeSockets["$clientIndex/$i"] = $socket;
 400                                 }
 401                         }
 402                         if ( !count( $readSockets ) && !count( $writeSockets ) ) {
 403                                 break;
 404                         }
 405                         $exceptSockets = null;
 406                         $timeout = min( $startTime + $this->timeout - microtime( true ), 1 );
 407                         wfSuppressWarnings();
 408                         $numReady = socket_select( $readSockets, $writeSockets, $exceptSockets, $timeout );
 409                         wfRestoreWarnings();
 410                         if ( $numReady === false ) {
 411                                 wfDebugLog( 'squid', __METHOD__.': Error in stream_select: ' .
 412                                         socket_strerror( socket_last_error() ) . "\n" );
 413                                 break;
 414                         }
 415                         // Check for timeout, use 1% tolerance since we aimed at having socket_select()
 416                         // exit at precisely the overall timeout
 417                         if ( microtime( true ) - $startTime > $this->timeout * 0.99 ) {
 418                                 wfDebugLog( 'squid', __CLASS__.": timeout ({$this->timeout}s)\n" );
 419                                 break;
 420                         } elseif ( !$numReady ) {
 421                                 continue;
 422                         }
 423
 424                         foreach ( $readSockets as $key => $socket ) {
 425                                 list( $clientIndex, ) = explode( '/', $key );
 426                                 $client = $this->clients[$clientIndex];
 427                                 $client->doReads();
 428                         }
 429                         foreach ( $writeSockets as $key => $socket ) {
 430                                 list( $clientIndex, ) = explode( '/', $key );
 431                                 $client = $this->clients[$clientIndex];
 432                                 $client->doWrites();
 433                         }
 434
 435                         $done = true;
 436                         foreach ( $this->clients as $client ) {
 437                                 if ( !$client->isIdle() ) {
 438                                         $done = false;
 439                                 }
 440                         }
 441                 }
 442                 foreach ( $this->clients as $client ) {
 443                         $client->close();
 444                 }
 445         }
 446 }