A statemachine is always uniquely identified by the combination of an entity
id and a machine name (that provides the relation to the statemachine the
entity is governed by).
the machine name should be a 'machine readable' string, since it will be stored in different
backends and might be used as a key there (eg: in redis).
The entity id is something that uniquely identifies a domain model. Probably
something that is stored in your application, like a primary key in a table, a GUID or a hash.
This object thus stores the minimum data needed from other processes in your
application domain to succesfully work with the statemachine.
public function isPersisted(Identifier $identifier)
{
$key = $identifier->getId();
if (!isset($_SESSION[$this->namespace][$key])) {
return false;
}
return true;
}
/**
*
* @param Identifier $identifier
* @param string $state
*/
public function __construct(Identifier $identifier, $state, $message = null)
{
$this->id = $identifier->getEntityId();
$this->machine = $identifier->getMachine();
$this->state = $state;
$this->timestamp = time();
$this->message = $message;
}
protected function build(Identifier $identifier)
{
$light = new TrafficLight($identifier->getEntityId());
return $light;
}
/**
* {@inheritDoc}
*/
public function isPersisted(Identifier $identifier)
{
$is_persisted = false;
try {
//https://php.net/manual/en/mongocollection.findone.php
$query = array("entity_id" => $identifier->getEntityId(), "machine" => $identifier->getMachine());
$data = $this->getClient()->izzum->states->findOne($query);
if ($data) {
$is_persisted = true;
}
} catch (\Exception $e) {
throw new Exception(sprintf('getting persistence info failed: [%s]', $e->getMessage()), Exception::PERSISTENCE_LAYER_EXCEPTION);
}
return $is_persisted;
}
/**
* {@inheritDoc}
*/
public function addHistory(Identifier $identifier, $state, $message = null, $is_exception = false)
{
$redis = $this->getRedis();
try {
$machine = $identifier->getMachine();
$entity_id = $identifier->getEntityId();
//counter for the number of transitions.
$key = self::KEY_COUNTERS_TRANSITIONS_ALL;
//this will function as the id of the transition data, stored as a redis hash
$counter = $redis->incr($key);
//now that we have the counter, start a redis multi command in pipeline mode
$redis->multi(\Redis::PIPELINE);
//create the record for the transition to store in a redis hash
$timestamp = time();
$record = array();
$record['state'] = $state;
$record['machine'] = $machine;
$record['entity_id'] = $entity_id;
if ($message) {
if (is_string($message)) {
$info = new \stdClass();
$info->message = $message;
$message = $info;
}
//always json_encode so we can pass objects as messages
$message = json_encode($message);
}
$record['message'] = $message;
$record['timestamp'] = $timestamp;
$record['datetime'] = date('Y-m-d H:i:s', $timestamp);
//ISO_8601
$record['exception'] = $is_exception ? 1 : 0;
$record['id'] = $counter;
/*
* set the canonical form of the transition as a hash with the counter as the id.
* This allows you to get data from the canonical from by storing a reference to the transaction id
* in other lists or sets (memory optimization) via:
* sort izzum:transitions:all:normal by nosort get izzum:transitions:canonical:*->message STORE mymessages
* @see http://redis.io/commands/sort
*/
$key_hash_id = sprintf(self::KEY_TRANSITIONS_CANONICAL, $counter);
$redis->hmset($key_hash_id, $record);
//store all transitions referencing the id of the canonical form in sorted sets (keyed by timestamp),
//set manipulations are powerful in redis (diff, union, intersect etc with the exceptions for example)
$key = self::KEY_TRANSITIONS_ALL;
$redis->zadd($key, $timestamp, $counter);
$key = sprintf(self::KEY_TRANSITIONS_MACHINES, $machine);
$redis->zadd($key, $timestamp, $counter);
$key = sprintf(self::KEY_TRANSITIONS_STATES, $machine, $state);
$redis->zadd($key, $timestamp, $counter);
$key = sprintf(self::KEY_TRANSITIONS_ENTITIES, $machine, $entity_id);
$redis->zadd($key, $timestamp, $counter);
if ($is_exception) {
//store all failed transitions referencing the id of the canonical form in sets
$key = self::KEY_TRANSITIONS_ALL_FAILED;
$redis->zadd($key, $timestamp, $counter);
$key = sprintf(self::KEY_TRANSITIONS_MACHINES_FAILED, $machine);
$redis->zadd($key, $timestamp, $counter);
$key = sprintf(self::KEY_TRANSITIONS_STATES_FAILED, $machine, $state);
$redis->zadd($key, $timestamp, $counter);
$key = sprintf(self::KEY_TRANSITIONS_ENTITIES_FAILED, $machine, $entity_id);
$redis->zadd($key, $timestamp, $counter);
}
//execute the sequence of redis commands
$redis->exec();
} catch (\Exception $e) {
$redis->discard();
throw new Exception(sprintf('adding history failed: [%s]', $e->getMessage()), Exception::PERSISTENCE_LAYER_EXCEPTION);
}
}
/**
*{@inheritDoc}
*/
public function addHistory(Identifier $identifier, $state, $message = null, $is_exception = false)
{
$connection = $this->getConnection();
$prefix = $this->getPrefix();
try {
$query = 'INSERT INTO ' . $prefix . 'statemachine_history
(machine, entity_id, state, message, changetime, exception)
VALUES
(:machine, :entity_id, :state, :message, :timestamp, :exception)';
$statement = $connection->prepare($query);
$machine = $identifier->getMachine();
$entity_id = $identifier->getEntityId();
$timestamp = $this->getTimestampForDriver();
$is_exception = $this->getBooleanForDriver($is_exception);
$statement->bindParam(":machine", $machine);
$statement->bindParam(":entity_id", $entity_id);
$statement->bindParam(":state", $state);
if ($message) {
if (is_string($message)) {
$info = new \stdClass();
$info->message = $message;
$message = $info;
}
//always json encode it so we can pass objects as the message and store it
$message = json_encode($message);
}
$statement->bindParam(":message", $message);
$statement->bindParam(":timestamp", $timestamp);
$statement->bindParam(":exception", $is_exception);
$result = $statement->execute();
if ($result === false) {
throw new Exception($this->getErrorInfo($statement));
}
} catch (\Exception $e) {
throw new Exception(sprintf('query for updating state failed: [%s]', $e->getMessage()), Exception::PERSISTENCE_LAYER_EXCEPTION);
}
}
public function getStorageFromRegistry(Identifier $identifier)
{
$registry = $this->getRegistry();
if (!isset($registry[$identifier->getId()])) {
$storage = null;
} else {
$storage = $registry[$identifier->getId()];
}
return $storage;
}
protected function build(Identifier $identifier)
{
$output = new \stdClass();
$output->entity_id = $identifier->getEntityId();
$output->machine = $identifier->getMachine();
return $output;
}