class-dedicated-sender.php
| 1 | <?php |
| 2 | /** |
| 3 | * Dedicated Sender. |
| 4 | * |
| 5 | * The class is responsible for spawning dedicated Sync requests. |
| 6 | * |
| 7 | * @package automattic/jetpack-sync |
| 8 | */ |
| 9 | |
| 10 | namespace Automattic\Jetpack\Sync; |
| 11 | |
| 12 | use WP_Error; |
| 13 | /** |
| 14 | * Class to manage Sync spawning. |
| 15 | * The purpose of this class is to provide the means to unblock Sync |
| 16 | * from running in the shutdown hook of regular requests by spawning a |
| 17 | * dedicated Sync request instead which will trigger Sync to run. |
| 18 | */ |
| 19 | class Dedicated_Sender { |
| 20 | |
| 21 | /** |
| 22 | * The transient name for storing the response code |
| 23 | * after spawning a dedicated sync test request. |
| 24 | */ |
| 25 | const DEDICATED_SYNC_CHECK_TRANSIENT = 'jetpack_sync_dedicated_sync_spawn_check'; |
| 26 | |
| 27 | /** |
| 28 | * Validation string to check if the endpoint is working correctly. |
| 29 | * |
| 30 | * This is extracted and not hardcoded, as we might want to change it in the future. |
| 31 | */ |
| 32 | const DEDICATED_SYNC_VALIDATION_STRING = 'DEDICATED SYNC OK'; |
| 33 | |
| 34 | /** |
| 35 | * Option name to use to keep the current request lock. |
| 36 | * |
| 37 | * The option format is `microtime(true)`. |
| 38 | */ |
| 39 | const DEDICATED_SYNC_REQUEST_LOCK_OPTION_NAME = 'jetpack_sync_dedicated_spawn_lock'; |
| 40 | |
| 41 | /** |
| 42 | * What's the timeout for the request lock in seconds. |
| 43 | * |
| 44 | * 5 seconds as default value seems sane, but we might want to adjust that in the future. |
| 45 | */ |
| 46 | const DEDICATED_SYNC_REQUEST_LOCK_TIMEOUT = 5; |
| 47 | |
| 48 | /** |
| 49 | * The query parameter name to use when passing the current lock id. |
| 50 | */ |
| 51 | const DEDICATED_SYNC_REQUEST_LOCK_QUERY_PARAM_NAME = 'request_lock_id'; |
| 52 | |
| 53 | /** |
| 54 | * The name of the transient to use to temporarily disable enabling of Dedicated sync. |
| 55 | */ |
| 56 | const DEDICATED_SYNC_TEMPORARY_DISABLE_FLAG = 'jetpack_sync_dedicated_sync_temp_disable'; |
| 57 | |
| 58 | /** |
| 59 | * Filter a URL to check if Dedicated Sync is enabled. |
| 60 | * We need to remove slashes and then run it through `urldecode` as sometimes the |
| 61 | * URL is in an encoded form, depending on server configuration. |
| 62 | * |
| 63 | * @param string $url The URL to filter. |
| 64 | * |
| 65 | * @return string |
| 66 | */ |
| 67 | public static function prepare_url_for_dedicated_request_check( $url ) { |
| 68 | return urldecode( $url ); |
| 69 | } |
| 70 | /** |
| 71 | * Check if this request should trigger Sync to run. |
| 72 | * |
| 73 | * @access public |
| 74 | * |
| 75 | * @return boolean True if this is a 'jetpack/v4/sync/spawn-sync', false otherwise. |
| 76 | */ |
| 77 | public static function is_dedicated_sync_request() { |
| 78 | /** |
| 79 | * Check $_SERVER['REQUEST_URI'] first, to see if we're in the right context. |
| 80 | * This is done to make sure we can hook in very early in the initialization of WordPress to |
| 81 | * be able to send sync requests to the backend as fast as possible, without needing to continue |
| 82 | * loading things for the request. |
| 83 | */ |
| 84 | if ( ! isset( $_SERVER['REQUEST_URI'] ) ) { |
| 85 | return false; |
| 86 | } |
| 87 | |
| 88 | // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized,WordPress.Security.NonceVerification.Recommended |
| 89 | $check_url = self::prepare_url_for_dedicated_request_check( wp_unslash( $_SERVER['REQUEST_URI'] ) ); |
| 90 | if ( strpos( $check_url, 'jetpack/v4/sync/spawn-sync' ) !== false ) { |
| 91 | return true; |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * If the above check failed, we might have an issue with detecting calls to the REST endpoint early on. |
| 96 | * Sometimes, like when permalinks are disabled, the REST path is sent via the `rest_route` GET parameter. |
| 97 | * We want to check it too, to make sure we managed to cover more cases and be more certain we actually |
| 98 | * catch calls to the endpoint. |
| 99 | */ |
| 100 | if ( ! isset( $_GET['rest_route'] ) ) { //phpcs:ignore WordPress.Security.NonceVerification.Recommended |
| 101 | return false; |
| 102 | } |
| 103 | |
| 104 | // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized,WordPress.Security.NonceVerification.Recommended |
| 105 | $check_url = self::prepare_url_for_dedicated_request_check( wp_unslash( $_GET['rest_route'] ) ); |
| 106 | if ( strpos( $check_url, 'jetpack/v4/sync/spawn-sync' ) !== false ) { |
| 107 | return true; |
| 108 | } |
| 109 | |
| 110 | return false; |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * Send a request to run Sync for a certain sync queue |
| 115 | * through HTTP request that doesn't halt page loading. |
| 116 | * |
| 117 | * @access public |
| 118 | * |
| 119 | * @param \Automattic\Jetpack\Sync\Queue $queue Queue object. |
| 120 | * |
| 121 | * @return boolean|WP_Error True if spawned, WP_Error otherwise. |
| 122 | */ |
| 123 | public static function spawn_sync( $queue ) { |
| 124 | if ( ! Settings::is_dedicated_sync_enabled() ) { |
| 125 | return new WP_Error( 'dedicated_sync_disabled', 'Dedicated Sync flow is disabled.' ); |
| 126 | } |
| 127 | |
| 128 | if ( $queue->is_locked() ) { |
| 129 | return new WP_Error( 'locked_queue_' . $queue->id ); |
| 130 | } |
| 131 | |
| 132 | if ( $queue->size() === 0 ) { |
| 133 | return new WP_Error( 'empty_queue_' . $queue->id ); |
| 134 | } |
| 135 | |
| 136 | // Return early if we've gotten a retry-after header response that is not expired. |
| 137 | $retry_time = get_option( Actions::RETRY_AFTER_PREFIX . $queue->id ); |
| 138 | if ( $retry_time && $retry_time >= microtime( true ) ) { |
| 139 | return new WP_Error( 'retry_after_' . $queue->id ); |
| 140 | } |
| 141 | |
| 142 | // Don't sync if we are throttled. |
| 143 | $sync_next_time = Sender::get_instance()->get_next_sync_time( $queue->id ); |
| 144 | if ( $sync_next_time > microtime( true ) ) { |
| 145 | return new WP_Error( 'sync_throttled_' . $queue->id ); |
| 146 | } |
| 147 | /** |
| 148 | * How much time to wait before we start suspecting Dedicated Sync is in trouble. |
| 149 | */ |
| 150 | $queue_send_time_threshold = 30 * MINUTE_IN_SECONDS; |
| 151 | |
| 152 | $queue_lag = $queue->lag(); |
| 153 | |
| 154 | // Only check if we're failing to send events if the queue lag is longer than the threshold. |
| 155 | if ( $queue_lag > $queue_send_time_threshold ) { |
| 156 | /** |
| 157 | * Check if Dedicated Sync is healthy and revert to Default Sync if such case is detected. |
| 158 | */ |
| 159 | $last_successful_queue_send_time = get_option( Actions::LAST_SUCCESS_PREFIX . $queue->id, null ); |
| 160 | |
| 161 | if ( $last_successful_queue_send_time === null ) { |
| 162 | /** |
| 163 | * No successful sync sending completed. This might be either a "new" sync site or a site that's totally stuck. |
| 164 | */ |
| 165 | self::on_dedicated_sync_lag_not_sending_threshold_reached(); |
| 166 | |
| 167 | return new WP_Error( 'dedicated_sync_not_sending', 'Dedicated Sync is not successfully sending events' ); |
| 168 | } else { |
| 169 | /** |
| 170 | * We have recorded a successful sending of events. Let's see if that is not too long ago in the past. |
| 171 | */ |
| 172 | $time_since_last_succesful_send = time() - $last_successful_queue_send_time; |
| 173 | |
| 174 | if ( $time_since_last_succesful_send > $queue_send_time_threshold ) { |
| 175 | // We haven't successfully sent stuff in more than 30 minutes. Revert to Default Sync |
| 176 | self::on_dedicated_sync_lag_not_sending_threshold_reached(); |
| 177 | |
| 178 | return new WP_Error( 'dedicated_sync_not_sending', 'Dedicated Sync is not successfully sending events' ); |
| 179 | } |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | /** |
| 184 | * Try to acquire a request lock, so we don't spawn multiple requests at the same time. |
| 185 | * This should prevent cases where sites might have limits on the amount of simultaneous requests. |
| 186 | */ |
| 187 | $request_lock = self::try_lock_spawn_request(); |
| 188 | if ( ! $request_lock ) { |
| 189 | return new WP_Error( 'dedicated_request_lock', 'Unable to acquire request lock' ); |
| 190 | } |
| 191 | |
| 192 | $url = rest_url( 'jetpack/v4/sync/spawn-sync' ); |
| 193 | $url = add_query_arg( 'time', time(), $url ); // Enforce Cache busting. |
| 194 | $url = add_query_arg( self::DEDICATED_SYNC_REQUEST_LOCK_QUERY_PARAM_NAME, $request_lock, $url ); |
| 195 | |
| 196 | $args = array( |
| 197 | 'cookies' => $_COOKIE, |
| 198 | 'blocking' => false, |
| 199 | 'timeout' => 0.01, |
| 200 | /** This filter is documented in wp-includes/class-wp-http-streams.php */ |
| 201 | 'sslverify' => apply_filters( 'https_local_ssl_verify', false ), |
| 202 | ); |
| 203 | |
| 204 | $result = wp_remote_get( $url, $args ); |
| 205 | if ( is_wp_error( $result ) ) { |
| 206 | return $result; |
| 207 | } |
| 208 | |
| 209 | return true; |
| 210 | } |
| 211 | |
| 212 | /** |
| 213 | * Attempt to acquire a request lock. |
| 214 | * |
| 215 | * To avoid spawning multiple requests at the same time, we need to have a quick lock that will |
| 216 | * allow only a single request to continue if we try to spawn multiple at the same time. |
| 217 | * |
| 218 | * @return false|mixed|string |
| 219 | */ |
| 220 | public static function try_lock_spawn_request() { |
| 221 | $current_microtime = (string) microtime( true ); |
| 222 | |
| 223 | $current_lock_value = \Jetpack_Options::get_raw_option( self::DEDICATED_SYNC_REQUEST_LOCK_OPTION_NAME, null ); |
| 224 | |
| 225 | if ( ! empty( $current_lock_value ) ) { |
| 226 | // Check if time has passed to overwrite the lock - min 5s? |
| 227 | if ( is_numeric( $current_lock_value ) && ( ( $current_microtime - $current_lock_value ) < self::DEDICATED_SYNC_REQUEST_LOCK_TIMEOUT ) ) { |
| 228 | // Still in previous lock, quit |
| 229 | return false; |
| 230 | } |
| 231 | |
| 232 | // If the value is not numeric (float/current time), we want to just overwrite it and continue. |
| 233 | } |
| 234 | |
| 235 | // Update. We don't want it to autoload, as we want to fetch it right before the checks. |
| 236 | \Jetpack_Options::update_raw_option( self::DEDICATED_SYNC_REQUEST_LOCK_OPTION_NAME, $current_microtime, false ); |
| 237 | // Give some time for the update to happen |
| 238 | usleep( wp_rand( 1000, 3000 ) ); |
| 239 | |
| 240 | $updated_value = \Jetpack_Options::get_raw_option( self::DEDICATED_SYNC_REQUEST_LOCK_OPTION_NAME, null ); |
| 241 | |
| 242 | if ( $updated_value === $current_microtime ) { |
| 243 | return $current_microtime; |
| 244 | } |
| 245 | |
| 246 | return false; |
| 247 | } |
| 248 | |
| 249 | /** |
| 250 | * Attempt to release the request lock. |
| 251 | * |
| 252 | * @param string $lock_id The request lock that's currently being held. |
| 253 | * |
| 254 | * @return bool|WP_Error |
| 255 | */ |
| 256 | public static function try_release_lock_spawn_request( $lock_id = '' ) { |
| 257 | // Try to get the lock_id from the current request if it's not supplied. |
| 258 | if ( empty( $lock_id ) ) { |
| 259 | $lock_id = self::get_request_lock_id_from_request(); |
| 260 | } |
| 261 | |
| 262 | // If it's still not a valid lock_id, throw an error and let the lock process figure it out. |
| 263 | if ( empty( $lock_id ) || ! is_numeric( $lock_id ) ) { |
| 264 | return new WP_Error( 'dedicated_request_lock_invalid', 'Invalid lock_id supplied for unlock' ); |
| 265 | } |
| 266 | |
| 267 | $current_lock_value = \Jetpack_Options::get_raw_option( self::DEDICATED_SYNC_REQUEST_LOCK_OPTION_NAME, null ); |
| 268 | |
| 269 | // If this is the flow that has the lock, let's release it so we can spawn other requests afterwards |
| 270 | if ( (string) $lock_id === $current_lock_value ) { |
| 271 | \Jetpack_Options::delete_raw_option( self::DEDICATED_SYNC_REQUEST_LOCK_OPTION_NAME ); |
| 272 | return true; |
| 273 | } |
| 274 | |
| 275 | return false; |
| 276 | } |
| 277 | |
| 278 | /** |
| 279 | * Try to get the request lock id from the current request. |
| 280 | * |
| 281 | * @return array|string|string[]|null |
| 282 | */ |
| 283 | public static function get_request_lock_id_from_request() { |
| 284 | // phpcs:ignore WordPress.Security.NonceVerification.Recommended |
| 285 | if ( ! isset( $_GET[ self::DEDICATED_SYNC_REQUEST_LOCK_QUERY_PARAM_NAME ] ) || ! is_numeric( $_GET[ self::DEDICATED_SYNC_REQUEST_LOCK_QUERY_PARAM_NAME ] ) ) { |
| 286 | return null; |
| 287 | } |
| 288 | |
| 289 | // phpcs:ignore WordPress.Security.NonceVerification.Recommended,WordPress.Security.ValidatedSanitizedInput.InputNotSanitized |
| 290 | return wp_unslash( $_GET[ self::DEDICATED_SYNC_REQUEST_LOCK_QUERY_PARAM_NAME ] ); |
| 291 | } |
| 292 | |
| 293 | /** |
| 294 | * Test Sync spawning functionality by making a request to the |
| 295 | * Sync spawning endpoint and storing the result (status code) in a transient. |
| 296 | * |
| 297 | * @since $$next_version$$ |
| 298 | * |
| 299 | * @return bool True if we got a successful response, false otherwise. |
| 300 | */ |
| 301 | public static function can_spawn_dedicated_sync_request() { |
| 302 | $dedicated_sync_check_transient = self::DEDICATED_SYNC_CHECK_TRANSIENT; |
| 303 | |
| 304 | $dedicated_sync_response_body = get_transient( $dedicated_sync_check_transient ); |
| 305 | |
| 306 | if ( false === $dedicated_sync_response_body ) { |
| 307 | $url = rest_url( 'jetpack/v4/sync/spawn-sync' ); |
| 308 | $url = add_query_arg( 'time', time(), $url ); // Enforce Cache busting. |
| 309 | $args = array( |
| 310 | 'cookies' => $_COOKIE, |
| 311 | 'timeout' => 30, |
| 312 | /** This filter is documented in wp-includes/class-wp-http-streams.php */ |
| 313 | 'sslverify' => apply_filters( 'https_local_ssl_verify', false ), |
| 314 | ); |
| 315 | |
| 316 | $response = wp_remote_get( $url, $args ); |
| 317 | $dedicated_sync_response_code = wp_remote_retrieve_response_code( $response ); |
| 318 | $dedicated_sync_response_body = trim( wp_remote_retrieve_body( $response ) ); |
| 319 | |
| 320 | /** |
| 321 | * Limit the size of the body that we save in the transient to avoid cases where an error |
| 322 | * occurs and a whole generated HTML page is returned. We don't need to store the whole thing. |
| 323 | * |
| 324 | * The regexp check is done to make sure we can detect the string even if the body returns some additional |
| 325 | * output, like some caching plugins do when they try to pad the request. |
| 326 | */ |
| 327 | $regexp = '!' . preg_quote( self::DEDICATED_SYNC_VALIDATION_STRING, '!' ) . '!uis'; |
| 328 | if ( preg_match( $regexp, $dedicated_sync_response_body ) ) { |
| 329 | $saved_response_body = self::DEDICATED_SYNC_VALIDATION_STRING; |
| 330 | } else { |
| 331 | $saved_response_body = time(); |
| 332 | } |
| 333 | |
| 334 | set_transient( $dedicated_sync_check_transient, $saved_response_body, HOUR_IN_SECONDS ); |
| 335 | |
| 336 | // Send a bit more information to WordPress.com to help debugging issues. |
| 337 | if ( $saved_response_body !== self::DEDICATED_SYNC_VALIDATION_STRING ) { |
| 338 | $data = array( |
| 339 | 'timestamp' => microtime( true ), |
| 340 | 'response_code' => $dedicated_sync_response_code, |
| 341 | 'response_body' => $dedicated_sync_response_body, |
| 342 | |
| 343 | // Send the flow type that was attempted. |
| 344 | 'sync_flow_type' => 'dedicated', |
| 345 | ); |
| 346 | |
| 347 | $sender = Sender::get_instance(); |
| 348 | |
| 349 | $sender->send_action( 'jetpack_sync_flow_error_enable', $data ); |
| 350 | } |
| 351 | } |
| 352 | |
| 353 | return self::DEDICATED_SYNC_VALIDATION_STRING === $dedicated_sync_response_body; |
| 354 | } |
| 355 | |
| 356 | /** |
| 357 | * Disable dedicated sync and set a transient to prevent re-enabling it for some time. |
| 358 | * |
| 359 | * @return void |
| 360 | */ |
| 361 | public static function on_dedicated_sync_lag_not_sending_threshold_reached() { |
| 362 | set_transient( self::DEDICATED_SYNC_TEMPORARY_DISABLE_FLAG, true, 6 * HOUR_IN_SECONDS ); |
| 363 | |
| 364 | Settings::update_settings( |
| 365 | array( |
| 366 | 'dedicated_sync_enabled' => 0, |
| 367 | ) |
| 368 | ); |
| 369 | |
| 370 | // Inform that we had to temporarily disable Dedicated Sync |
| 371 | $data = array( |
| 372 | 'timestamp' => microtime( true ), |
| 373 | |
| 374 | // Send the flow type that was attempted. |
| 375 | 'sync_flow_type' => 'dedicated', |
| 376 | ); |
| 377 | |
| 378 | $sender = Sender::get_instance(); |
| 379 | |
| 380 | $sender->send_action( 'jetpack_sync_flow_error_temp_disable', $data ); |
| 381 | } |
| 382 | |
| 383 | /** |
| 384 | * Disable or enable Dedicated Sync sender based on the header value returned from WordPress.com |
| 385 | * |
| 386 | * @param string $dedicated_sync_header The Dedicated Sync header value - `on` or `off`. |
| 387 | * |
| 388 | * @return bool Whether Dedicated Sync is going to be enabled or not. |
| 389 | */ |
| 390 | public static function maybe_change_dedicated_sync_status_from_wpcom_header( $dedicated_sync_header ) { |
| 391 | $dedicated_sync_enabled = 'on' === $dedicated_sync_header ? 1 : 0; |
| 392 | |
| 393 | // Prevent enabling of Dedicated sync via header flag if we're in an autoheal timeout. |
| 394 | if ( $dedicated_sync_enabled ) { |
| 395 | $check_transient = get_transient( self::DEDICATED_SYNC_TEMPORARY_DISABLE_FLAG ); |
| 396 | |
| 397 | if ( $check_transient ) { |
| 398 | // Something happened and Dedicated Sync should not be automatically re-enabled. |
| 399 | return false; |
| 400 | } |
| 401 | } |
| 402 | |
| 403 | Settings::update_settings( |
| 404 | array( |
| 405 | 'dedicated_sync_enabled' => $dedicated_sync_enabled, |
| 406 | ) |
| 407 | ); |
| 408 | |
| 409 | return Settings::is_dedicated_sync_enabled(); |
| 410 | } |
| 411 | } |
| 412 |