Detailed explanation of beanstalkd message queue in php and sharing of classes

This article mainly shares the php-beanstalkd message queue class example code for everyone, which has certain reference value. Interested friends can refer to

Overview:
Beanstalkd, a high-level A high-performance, lightweight distributed memory queue system, originally designed to reduce the page access delay of high-volume web application systems by asynchronously executing time-consuming tasks in the background, it has supported the Facebook Causes application with 9.5 million users. Later it was open sourced, and now PostRank is deployed and used on a large scale, processing millions of tasks every day. Beanstalkd is a typical Memcached-like design. The protocol and usage are the same, so users who have used memcached will feel that Beanstalkd looks familiar.
Beanstalk core concepts:
job: A task that requires asynchronous processing needs to be placed in a tube.
tube: A well-known task queue used to store jobs of a uniform type
producer: the producer of the job
consumer: the consumer of the job
In short, the process is just one sentence:
The producer generates a task job and pushes the job into a tube.
Then the consumer takes out the job from the tube and executes it (of course, the premise of all these operations is that the beanstalk service is running).

A job has READY (always ready to be taken out by a consumer), RESERVED (the task is being processed by a consumer), DELAYED (delays the task and enters the ready state after the set delay time), BURIED ( During hibernation, the state needs to be transferred before operation) four states. When the producer directly puts a job, the job is in the READY state, waiting for the consumer to process it. If you choose to delay the put, the job will first enter the DELAYED state, and then migrate to the READY state after the waiting time. After the consumer obtains the current READY job, the status of the job is migrated to RESERVED, so that other consumers can no longer operate the job. After the consumer completes the job, it can choose delete, release or bury operation; after delete, the job dies from the system and cannot be obtained again; the release operation can migrate the job status back to READY (it can also delay the status migration operation). This allows other consumers to continue to obtain and execute the job; the interesting thing is the bury operation, which can put the job to sleep, and then kick the dormant job back to the READY state when needed, or delete the job in the BURIED state. It is precisely because of these interesting operations and states that many interesting applications can be made based on them. For example, if you want to implement a circular queue, you can sleep the jobs in the RESERVED state, and then put the BURIED state jobs to work when there are no jobs in the READY state. The job kicks back to the READY state in one go.

Example analysis: Weibo is a very typical example:
1, post a Weibo
2, push it to his fans (if there are 1 million fans, this place will be blocked for a long time, What users feel is delay)
To publish a piece of content on Weibo, you need to do the above two things to be complete. Posting a Weibo only requires a simple database operation,
but the fans who push it to him The database needs to be operated 1,000,000 times, causing users to wait for a long delay before sending a successful result.
Using the queue method, the user sends a Weibo and the result is returned immediately. If the sending is successful, the remaining push will be put into the queue for asynchronous execution.
The push does not need to be particularly timely, and the delay will be more than a few seconds or dozens of seconds. This is acceptable.

The example in this article shares the specific code of the php beanstalkd message queue class for your reference. The specific content is as follows

<?php
namespace Common\Business;
/**
 * beanstalk: A minimalistic PHP beanstalk client.
 *
 * Copyright (c) 2009-2015 David Persson
 *
 * Distributed under the terms of the MIT License.
 * Redistributions of files must retain the above copyright notice.
 */
 
use RuntimeException;
 
/**
 * An interface to the beanstalk queue service. Implements the beanstalk
 * protocol spec 1.9. Where appropriate the documentation from the protocol
 * has been added to the docblocks in this class.
 *
 * @link https://github.com/kr/beanstalkd/blob/master/doc/protocol.txt
 */
class BeanStalk {
 
  /**
   * Minimum priority value which can be assigned to a job. The minimum
   * priority value is also the _highest priority_ a job can have.
   *
   * @var integer
   */
  const MIN_PRIORITY = 0;
 
  /**
   * Maximum priority value which can be assigned to a job. The maximum
   * priority value is also the _lowest priority_ a job can have.
   *
   * @var integer
   */
  const MAX_PRIORITY = 4294967295;
 
  /**
   * Holds a boolean indicating whether a connection to the server is
   * currently established or not.
   *
   * @var boolean
   */
  public $connected = false;
 
  /**
   * Holds configuration values.
   *
   * @var array
   */
  protected $_config = [];
 
  /**
   * The current connection resource handle (if any).
   *
   * @var resource
   */
  protected $_connection;
 
  /**
   * Constructor.
   *
   * @param array $config An array of configuration values:
   *    - `&#39;persistent&#39;` Whether to make the connection persistent or
   *             not, defaults to `true` as the FAQ recommends
   *             persistent connections.
   *    - `&#39;host&#39;`    The beanstalk server hostname or IP address to
   *             connect to, defaults to `127.0.0.1`.
   *    - `&#39;port&#39;`    The port of the server to connect to, defaults
   *             to `11300`.
   *    - `&#39;timeout&#39;`   Timeout in seconds when establishing the
   *             connection, defaults to `1`.
   *    - `&#39;logger&#39;`   An instance of a PSR-3 compatible logger.
   *
   * @link https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-3-logger-interface.md
   * @return void
   */
  public function __construct(array $config = []) {
    $defaults = [
      &#39;persistent&#39; => true,
      &#39;host&#39; => &#39;127.0.0.1&#39;,
      &#39;port&#39; => 11300,
      &#39;timeout&#39; => 1,
      &#39;logger&#39; => null
    ];
    $this->_config = $config + $defaults;
  }
 
  /**
   * Destructor, disconnects from the server.
   *
   * @return void
   */
  public function __destruct() {
    $this->disconnect();
  }
 
  /**
   * Initiates a socket connection to the beanstalk server. The resulting
   * stream will not have any timeout set on it. Which means it can wait
   * an unlimited amount of time until a packet becomes available. This
   * is required for doing blocking reads.
   *
   * @see \Beanstalk\Client::$_connection
   * @see \Beanstalk\Client::reserve()
   * @return boolean `true` if the connection was established, `false` otherwise.
   */
  public function connect() {
    if (isset($this->_connection)) {
      $this->disconnect();
    }
    $errNum = &#39;&#39;;
    $errStr = &#39;&#39;;
    $function = $this->_config[&#39;persistent&#39;] ? &#39;pfsockopen&#39; : &#39;fsockopen&#39;;
    $params = [$this->_config[&#39;host&#39;], $this->_config[&#39;port&#39;], &$errNum, &$errStr];
 
    if ($this->_config[&#39;timeout&#39;]) {
      $params[] = $this->_config[&#39;timeout&#39;];
    }
    $this->_connection = @call_user_func_array($function, $params);
 
    if (!empty($errNum) || !empty($errStr)) {
      $this->_error("{$errNum}: {$errStr}");
    }
 
    $this->connected = is_resource($this->_connection);
 
    if ($this->connected) {
      stream_set_timeout($this->_connection, -1);
    }
    return $this->connected;
  }
 
  /**
   * Closes the connection to the beanstalk server by first signaling
   * that we want to quit then actually closing the socket connection.
   *
   * @return boolean `true` if diconnecting was successful.
   */
  public function disconnect() {
    if (!is_resource($this->_connection)) {
      $this->connected = false;
    } else {
      $this->_write(&#39;quit&#39;);
      $this->connected = !fclose($this->_connection);
 
      if (!$this->connected) {
        $this->_connection = null;
      }
    }
    return !$this->connected;
  }
 
  /**
   * Pushes an error message to the logger, when one is configured.
   *
   * @param string $message The error message.
   * @return void
   */
  protected function _error($message) {
    if ($this->_config[&#39;logger&#39;]) {
      $this->_config[&#39;logger&#39;]->error($message);
    }
  }
 
  public function errors()
  {
    return $this->_config[&#39;logger&#39;];
  }
  /**
   * Writes a packet to the socket. Prior to writing to the socket will
   * check for availability of the connection.
   *
   * @param string $data
   * @return integer|boolean number of written bytes or `false` on error.
   */
  protected function _write($data) {
    if (!$this->connected) {
      $message = &#39;No connecting found while writing data to socket.&#39;;
      throw new RuntimeException($message);
    }
 
    $data .= "\r\n";
    return fwrite($this->_connection, $data, strlen($data));
  }
 
  /**
   * Reads a packet from the socket. Prior to reading from the socket
   * will check for availability of the connection.
   *
   * @param integer $length Number of bytes to read.
   * @return string|boolean Data or `false` on error.
   */
  protected function _read($length = null) {
    if (!$this->connected) {
      $message = &#39;No connection found while reading data from socket.&#39;;
      throw new RuntimeException($message);
    }
    if ($length) {
      if (feof($this->_connection)) {
        return false;
      }
      $data = stream_get_contents($this->_connection, $length + 2);
      $meta = stream_get_meta_data($this->_connection);
 
      if ($meta[&#39;timed_out&#39;]) {
        $message = &#39;Connection timed out while reading data from socket.&#39;;
        throw new RuntimeException($message);
      }
      $packet = rtrim($data, "\r\n");
    } else {
      $packet = stream_get_line($this->_connection, 16384, "\r\n");
    }
    return $packet;
  }
 
  /* Producer Commands */
 
  /**
   * The `put` command is for any process that wants to insert a job into the queue.
   *
   * @param integer $pri Jobs with smaller priority values will be scheduled
   *    before jobs with larger priorities. The most urgent priority is
   *    0; the least urgent priority is 4294967295.
   * @param integer $delay Seconds to wait before putting the job in the
   *    ready queue. The job will be in the "delayed" state during this time.
   * @param integer $ttr Time to run - Number of seconds to allow a worker to
   *    run this job. The minimum ttr is 1.
   * @param string $data The job body.
   * @return integer|boolean `false` on error otherwise an integer indicating
   *     the job id.
   */
  public function put($pri, $delay, $ttr, $data) {
    $this->_write(sprintf("put %d %d %d %d\r\n%s", $pri, $delay, $ttr, strlen($data), $data));
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;INSERTED&#39;:
      case &#39;BURIED&#39;:
        return (integer) strtok(&#39; &#39;); // job id
      case &#39;EXPECTED_CRLF&#39;:
      case &#39;JOB_TOO_BIG&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * The `use` command is for producers. Subsequent put commands will put
   * jobs into the tube specified by this command. If no use command has
   * been issued, jobs will be put into the tube named `default`.
   *
   * @param string $tube A name at most 200 bytes. It specifies the tube to
   *    use. If the tube does not exist, it will be created.
   * @return string|boolean `false` on error otherwise the name of the tube.
   */
  public function useTube($tube) {
    $this->_write(sprintf(&#39;use %s&#39;, $tube));
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;USING&#39;:
        return strtok(&#39; &#39;);
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Pause a tube delaying any new job in it being reserved for a given time.
   *
   * @param string $tube The name of the tube to pause.
   * @param integer $delay Number of seconds to wait before reserving any more
   *    jobs from the queue.
   * @return boolean `false` on error otherwise `true`.
   */
  public function pauseTube($tube, $delay) {
    $this->_write(sprintf(&#39;pause-tube %s %d&#39;, $tube, $delay));
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;PAUSED&#39;:
        return true;
      case &#39;NOT_FOUND&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /* Worker Commands */
 
  /**
   * Reserve a job (with a timeout).
   *
   * @param integer $timeout If given specifies number of seconds to wait for
   *    a job. `0` returns immediately.
   * @return array|false `false` on error otherwise an array holding job id
   *     and body.
   */
  public function reserve($timeout = null) {
    if (isset($timeout)) {
      $this->_write(sprintf(&#39;reserve-with-timeout %d&#39;, $timeout));
    } else {
      $this->_write(&#39;reserve&#39;);
    }
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;RESERVED&#39;:
        return [
          &#39;id&#39; => (integer) strtok(&#39; &#39;),
          &#39;body&#39; => $this->_read((integer) strtok(&#39; &#39;))
        ];
      case &#39;DEADLINE_SOON&#39;:
      case &#39;TIMED_OUT&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Removes a job from the server entirely.
   *
   * @param integer $id The id of the job.
   * @return boolean `false` on error, `true` on success.
   */
  public function delete($id) {
    $this->_write(sprintf(&#39;delete %d&#39;, $id));
    $status = $this->_read();
 
    switch ($status) {
      case &#39;DELETED&#39;:
        return true;
      case &#39;NOT_FOUND&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Puts a reserved job back into the ready queue.
   *
   * @param integer $id The id of the job.
   * @param integer $pri Priority to assign to the job.
   * @param integer $delay Number of seconds to wait before putting the job in the ready queue.
   * @return boolean `false` on error, `true` on success.
   */
  public function release($id, $pri, $delay) {
    $this->_write(sprintf(&#39;release %d %d %d&#39;, $id, $pri, $delay));
    $status = $this->_read();
 
    switch ($status) {
      case &#39;RELEASED&#39;:
      case &#39;BURIED&#39;:
        return true;
      case &#39;NOT_FOUND&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Puts a job into the `buried` state Buried jobs are put into a FIFO
   * linked list and will not be touched until a client kicks them.
   *
   * @param integer $id The id of the job.
   * @param integer $pri *New* priority to assign to the job.
   * @return boolean `false` on error, `true` on success.
   */
  public function bury($id, $pri) {
    $this->_write(sprintf(&#39;bury %d %d&#39;, $id, $pri));
    $status = $this->_read();
 
    switch ($status) {
      case &#39;BURIED&#39;:
        return true;
      case &#39;NOT_FOUND&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Allows a worker to request more time to work on a job.
   *
   * @param integer $id The id of the job.
   * @return boolean `false` on error, `true` on success.
   */
  public function touch($id) {
    $this->_write(sprintf(&#39;touch %d&#39;, $id));
    $status = $this->_read();
 
    switch ($status) {
      case &#39;TOUCHED&#39;:
        return true;
      case &#39;NOT_TOUCHED&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Adds the named tube to the watch list for the current connection.
   *
   * @param string $tube Name of tube to watch.
   * @return integer|boolean `false` on error otherwise number of tubes in watch list.
   */
  public function watch($tube) {
    $this->_write(sprintf(&#39;watch %s&#39;, $tube));
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;WATCHING&#39;:
        return (integer) strtok(&#39; &#39;);
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Remove the named tube from the watch list.
   *
   * @param string $tube Name of tube to ignore.
   * @return integer|boolean `false` on error otherwise number of tubes in watch list.
   */
  public function ignore($tube) {
    $this->_write(sprintf(&#39;ignore %s&#39;, $tube));
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;WATCHING&#39;:
        return (integer) strtok(&#39; &#39;);
      case &#39;NOT_IGNORED&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /* Other Commands */
 
  /**
   * Inspect a job by its id.
   *
   * @param integer $id The id of the job.
   * @return string|boolean `false` on error otherwise the body of the job.
   */
  public function peek($id) {
    $this->_write(sprintf(&#39;peek %d&#39;, $id));
    return $this->_peekRead();
  }
 
  /**
   * Inspect the next ready job.
   *
   * @return string|boolean `false` on error otherwise the body of the job.
   */
  public function peekReady() {
    $this->_write(&#39;peek-ready&#39;);
    return $this->_peekRead();
  }
 
  /**
   * Inspect the job with the shortest delay left.
   *
   * @return string|boolean `false` on error otherwise the body of the job.
   */
  public function peekDelayed() {
    $this->_write(&#39;peek-delayed&#39;);
    return $this->_peekRead();
  }
 
  /**
   * Inspect the next job in the list of buried jobs.
   *
   * @return string|boolean `false` on error otherwise the body of the job.
   */
  public function peekBuried() {
    $this->_write(&#39;peek-buried&#39;);
    return $this->_peekRead();
  }
 
  /**
   * Handles response for all peek methods.
   *
   * @return string|boolean `false` on error otherwise the body of the job.
   */
  protected function _peekRead() {
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;FOUND&#39;:
        return [
          &#39;id&#39; => (integer) strtok(&#39; &#39;),
          &#39;body&#39; => $this->_read((integer) strtok(&#39; &#39;))
        ];
      case &#39;NOT_FOUND&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Moves jobs into the ready queue (applies to the current tube).
   *
   * If there are buried jobs those get kicked only otherwise delayed
   * jobs get kicked.
   *
   * @param integer $bound Upper bound on the number of jobs to kick.
   * @return integer|boolean False on error otherwise number of jobs kicked.
   */
  public function kick($bound) {
    $this->_write(sprintf(&#39;kick %d&#39;, $bound));
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;KICKED&#39;:
        return (integer) strtok(&#39; &#39;);
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * This is a variant of the kick command that operates with a single
   * job identified by its job id. If the given job id exists and is in a
   * buried or delayed state, it will be moved to the ready queue of the
   * the same tube where it currently belongs.
   *
   * @param integer $id The job id.
   * @return boolean `false` on error `true` otherwise.
   */
  public function kickJob($id) {
    $this->_write(sprintf(&#39;kick-job %d&#39;, $id));
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;KICKED&#39;:
        return true;
      case &#39;NOT_FOUND&#39;:
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /* Stats Commands */
 
  /**
   * Gives statistical information about the specified job if it exists.
   *
   * @param integer $id The job id.
   * @return string|boolean `false` on error otherwise a string with a yaml formatted dictionary.
   */
  public function statsJob($id) {
    $this->_write(sprintf(&#39;stats-job %d&#39;, $id));
    return $this->_statsRead();
  }
 
  /**
   * Gives statistical information about the specified tube if it exists.
   *
   * @param string $tube Name of the tube.
   * @return string|boolean `false` on error otherwise a string with a yaml formatted dictionary.
   */
  public function statsTube($tube) {
    $this->_write(sprintf(&#39;stats-tube %s&#39;, $tube));
    return $this->_statsRead();
  }
 
  /**
   * Gives statistical information about the system as a whole.
   *
   * @return string|boolean `false` on error otherwise a string with a yaml formatted dictionary.
   */
  public function stats() {
    $this->_write(&#39;stats&#39;);
    return $this->_statsRead();
  }
 
  /**
   * Returns a list of all existing tubes.
   *
   * @return string|boolean `false` on error otherwise a string with a yaml formatted list.
   */
  public function listTubes() {
    $this->_write(&#39;list-tubes&#39;);
    return $this->_statsRead();
  }
 
  /**
   * Returns the tube currently being used by the producer.
   *
   * @return string|boolean `false` on error otherwise a string with the name of the tube.
   */
  public function listTubeUsed() {
    $this->_write(&#39;list-tube-used&#39;);
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;USING&#39;:
        return strtok(&#39; &#39;);
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Returns a list of tubes currently being watched by the worker.
   *
   * @return string|boolean `false` on error otherwise a string with a yaml formatted list.
   */
  public function listTubesWatched() {
    $this->_write(&#39;list-tubes-watched&#39;);
    return $this->_statsRead();
  }
 
  /**
   * Handles responses for all stat methods.
   *
   * @param boolean $decode Whether to decode data before returning it or not. Default is `true`.
   * @return array|string|boolean `false` on error otherwise statistical data.
   */
  protected function _statsRead($decode = true) {
    $status = strtok($this->_read(), &#39; &#39;);
 
    switch ($status) {
      case &#39;OK&#39;:
        $data = $this->_read((integer) strtok(&#39; &#39;));
        return $decode ? $this->_decode($data) : $data;
      default:
        $this->_error($status);
        return false;
    }
  }
 
  /**
   * Decodes YAML data. This is a super naive decoder which just works on
   * a subset of YAML which is commonly returned by beanstalk.
   *
   * @param string $data The data in YAML format, can be either a list or a dictionary.
   * @return array An (associative) array of the converted data.
   */
  protected function _decode($data) {
    $data = array_slice(explode("\n", $data), 1);
    $result = [];
 
    foreach ($data as $key => $value) {
      if ($value[0] === &#39;-&#39;) {
        $value = ltrim($value, &#39;- &#39;);
      } elseif (strpos($value, &#39;:&#39;) !== false) {
        list($key, $value) = explode(&#39;:&#39;, $value);
        $value = ltrim($value, &#39; &#39;);
      }
      if (is_numeric($value)) {
        $value = (integer) $value == $value ? (integer) $value : (float) $value;
      }
      $result[$key] = $value;
    }
    return $result;
  }
}
 
?>

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