DominionEnterprises\Mongo\Queue

Complexity

Total Complexity

58

Size/Duplication

Total Lines	466
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	0

Importance

Changes	14
Bugs	0	Features	2

12 Methods

Rating	Name	Duplication	Size	Complexity
B	__construct()	0	23	5
A	ensureGetIndex()	0	20	1
A	ensureCountIndex()	0	16	3
C	get()	0	69	12
A	count()	0	16	4
A	ack()	0	13	3
D	ackSend()	0	45	9
A	requeue()	0	6	1
B	send()	0	28	4
C	ensureIndex()	0	32	8
B	verifySort()	0	16	5
A	verifyQuery()	0	10	3

<?php
/**
 * Defines the DominionEnterprises\Mongo\Queue class.
 */

namespace DominionEnterprises\Mongo;

/**
 * Abstraction of mongo db collection as priority queue.
 *
 * Tied priorities are ordered by time. So you may use a single priority for normal queuing (default args exist for
 * this purpose).  Using a random priority achieves random get()
 */
final class Queue implements QueueInterface
{
    const MONGO_INT32_MAX = 2147483647;//2147483648 can overflow in php mongo without using the MongoInt64

    /**
     * mongo collection to use for queue.
     *
     * @var \MongoCollection
     */
    private $collection;

    /**
     * Construct queue.
     *
     * @param \MongoCollection|string $collectionOrUrl A MongoCollection instance or the mongo connection url.
     * @param string $db the mongo db name
     * @param string $collection the collection name to use for the queue
     *
     * @throws \InvalidArgumentException $collectionOrUrl, $db or $collection was not a string
     */
    public function __construct($collectionOrUrl, $db = null, $collection = null)
    {
        if ($collectionOrUrl instanceof \MongoCollection) {
            $this->collection = $collectionOrUrl;
            return;
        }

        if (!is_string($collectionOrUrl)) {
            throw new \InvalidArgumentException('$collectionOrUrl was not a string');
        }

        if (!is_string($db)) {
            throw new \InvalidArgumentException('$db was not a string');
        }

        if (!is_string($collection)) {
            throw new \InvalidArgumentException('$collection was not a string');
        }

        $mongo = new \MongoClient($collectionOrUrl);
        $mongoDb = $mongo->selectDB($db);
        $this->collection = $mongoDb->selectCollection($collection);
    }

    /**
     * Ensure an index for the get() method.
     *
     * @param array $beforeSort Fields in get() call to index before the sort field in same format
     *                          as \MongoCollection::ensureIndex()
     * @param array $afterSort  Fields in get() call to index after the sort field in same format as
     *                          \MongoCollection::ensureIndex()
     *
     * @return void
     *
     * @throws \InvalidArgumentException value of $beforeSort or $afterSort is not 1 or -1 for ascending and descending
     * @throws \InvalidArgumentException key in $beforeSort or $afterSort was not a string
     */
    public function ensureGetIndex(array $beforeSort = [], array $afterSort = [])
    {
        //using general rule: equality, sort, range or more equality tests in that order for index
        $completeFields = ['running' => 1];

        self::verifySort($beforeSort, 'beforeSort', $completeFields);

        $completeFields['priority'] = 1;
        $completeFields['created'] = 1;

        self::verifySort($afterSort, 'afterSort', $completeFields);

        $completeFields['earliestGet'] = 1;

        //for the main query in get()
        $this->ensureIndex($completeFields);

        //for the stuck messages query in get()
        $this->ensureIndex(['running' => 1, 'resetTimestamp' => 1]);
    }

    /**
     * Ensure an index for the count() method.
     * Is a no-op if the generated index is a prefix of an existing one. If you have a similar ensureGetIndex call,
     * call it first.
     *
     * @param array $fields fields in count() call to index in same format as \MongoCollection::ensureIndex()
     * @param bool $includeRunning whether to include the running field in the index
     *
     * @return void
     *
     * @throws \InvalidArgumentException $includeRunning was not a boolean
     * @throws \InvalidArgumentException key in $fields was not a string
     * @throws \InvalidArgumentException value of $fields is not 1 or -1 for ascending and descending
     */
    public function ensureCountIndex(array $fields, $includeRunning)
    {
        if (!is_bool($includeRunning)) {
            throw new \InvalidArgumentException('$includeRunning was not a boolean');
        }

        $completeFields = [];

        if ($includeRunning) {
            $completeFields['running'] = 1;
        }

        self::verifySort($fields, 'fields', $completeFields);

        $this->ensureIndex($completeFields);
    }

    /**
     * Get a non running message from the queue.
     *
     * @param array $query in same format as \MongoCollection::find() where top level fields do not contain operators.
     *                     Lower level fields can however. eg: valid {a: {$gt: 1}, "b.c": 3},
     *                     invalid {$and: [{...}, {...}]}
     * @param int $runningResetDuration second duration the message can stay unacked before it resets and can be
     *                                  retreived again.
     * @param int $waitDurationInMillis millisecond duration to wait for a message.
     * @param int $pollDurationInMillis millisecond duration to wait between polls.
     *
     * @return array|null the message or null if one is not found
     *
     * @throws \InvalidArgumentException $runningResetDuration, $waitDurationInMillis or $pollDurationInMillis was not
     *                                   an int
     * @throws \InvalidArgumentException key in $query was not a string
     */
    public function get(array $query, $runningResetDuration, $waitDurationInMillis = 3000, $pollDurationInMillis = 200)
    {
        if (!is_int($runningResetDuration)) {
            throw new \InvalidArgumentException('$runningResetDuration was not an int');
        }

        if (!is_int($waitDurationInMillis)) {
            throw new \InvalidArgumentException('$waitDurationInMillis was not an int');
        }

        if (!is_int($pollDurationInMillis)) {
            throw new \InvalidArgumentException('$pollDurationInMillis was not an int');
        }

        if ($pollDurationInMillis < 0) {
            $pollDurationInMillis = 0;
        }

        //reset stuck messages
        $this->collection->update(
            ['running' => true, 'resetTimestamp' => ['$lte' => new \MongoDate()]],
            ['$set' => ['running' => false]],
            ['multiple' => true]
        );

        $completeQuery = ['running' => false];
        self::verifyQuery($query, $completeQuery);
        $completeQuery['earliestGet'] = ['$lte' => new \MongoDate()];

        $resetTimestamp = time() + $runningResetDuration;
        //ints overflow to floats
        if (!is_int($resetTimestamp)) {
            $resetTimestamp = $runningResetDuration > 0 ? self::MONGO_INT32_MAX : 0;
        }

        $update = ['$set' => ['resetTimestamp' => new \MongoDate($resetTimestamp), 'running' => true]];
        $fields = ['payload' => 1];
        $options = ['sort' => ['priority' => 1, 'created' => 1]];

        //ints overflow to floats, should be fine
        $end = microtime(true) + ($waitDurationInMillis / 1000.0);

        $sleepTime = $pollDurationInMillis * 1000;
        //ints overflow to floats and already checked $pollDurationInMillis was positive
        if (!is_int($sleepTime)) {
            //ignore since testing a giant sleep takes too long
            //@codeCoverageIgnoreStart
            $sleepTime = PHP_INT_MAX;
        }   //@codeCoverageIgnoreEnd

        while (true) {
            $message = $this->collection->findAndModify($completeQuery, $update, $fields, $options);
            //checking if _id exist because findAndModify doesnt seem to return null when it can't match the query on
            //older mongo extension
            if ($message !== null && array_key_exists('_id', $message)) {
                //id on left of union operator so a possible id in payload doesnt wipe it out the generated one
                return ['id' => $message['_id']] + $message['payload'];
            }

            if (microtime(true) >= $end) {
                return null;
            }

            usleep($sleepTime);
        }

        //ignore since always return from the function from the while loop
        //@codeCoverageIgnoreStart
    }
    //@codeCoverageIgnoreEnd

    /**
     * Count queue messages.
     *
     * @param array $query in same format as \MongoCollection::find() where top level fields do not contain operators.
     * Lower level fields can however. eg: valid {a: {$gt: 1}, "b.c": 3}, invalid {$and: [{...}, {...}]}
     * @param bool|null $running query a running message or not or all
     *
     * @return int the count
     *
     * @throws \InvalidArgumentException $running was not null and not a bool
     * @throws \InvalidArgumentException key in $query was not a string
     */
    public function count(array $query, $running = null)
    {
        if ($running !== null && !is_bool($running)) {
            throw new \InvalidArgumentException('$running was not null and not a bool');
        }

        $totalQuery = [];

        if ($running !== null) {
            $totalQuery['running'] = $running;
        }

        self::verifyQuery($query, $totalQuery);

        return $this->collection->count($totalQuery);
    }

    /**
     * Acknowledge a message was processed and remove from queue.
     *
     * @param array $message message received from get()
     *
     * @return void
     *
     * @throws \InvalidArgumentException $message does not have a field "id" that is a MongoId
     */
    public function ack(array $message)
    {
        $id = null;
        if (array_key_exists('id', $message)) {
            $id = $message['id'];
        }

        if (!($id instanceof \MongoId)) {
            throw new \InvalidArgumentException('$message does not have a field "id" that is a MongoId');
        }

        $this->collection->remove(['_id' => $id]);
    }

    /**
     * Atomically acknowledge and send a message to the queue.
     *
     * @param array $message the message to ack received from get()
     * @param array $payload the data to store in the message to send. Data is handled same way
     *                       as \MongoCollection::insert()
     * @param int $earliestGet earliest unix timestamp the message can be retreived.
     * @param float $priority priority for order out of get(). 0 is higher priority than 1
     * @param bool $newTimestamp true to give the payload a new timestamp or false to use given message timestamp
     *
     * @return void
     *
     * @throws \InvalidArgumentException $message does not have a field "id" that is a MongoId
     * @throws \InvalidArgumentException $earliestGet was not an int
     * @throws \InvalidArgumentException $priority was not a float
     * @throws \InvalidArgumentException $priority is NaN
     * @throws \InvalidArgumentException $newTimestamp was not a bool
     */
    public function ackSend(array $message, array $payload, $earliestGet = 0, $priority = 0.0, $newTimestamp = true)
    {
        $id = null;
        if (array_key_exists('id', $message)) {
            $id = $message['id'];
        }

        if (!($id instanceof \MongoId)) {
            throw new \InvalidArgumentException('$message does not have a field "id" that is a MongoId');
        }

        if (!is_int($earliestGet)) {
            throw new \InvalidArgumentException('$earliestGet was not an int');
        }

        if (!is_float($priority)) {
            throw new \InvalidArgumentException('$priority was not a float');
        }

        if (is_nan($priority)) {
            throw new \InvalidArgumentException('$priority was NaN');
        }

        if ($newTimestamp !== true && $newTimestamp !== false) {
            throw new \InvalidArgumentException('$newTimestamp was not a bool');
        }

        //Ensure $earliestGet is between 0 and MONGO_INT32_MAX
        $earliestGet = min(max(0, $earliestGet), self::MONGO_INT32_MAX);

        $toSet = [
            'payload' => $payload,
            'running' => false,
            'resetTimestamp' => new \MongoDate(self::MONGO_INT32_MAX),
            'earliestGet' => new \MongoDate($earliestGet),
            'priority' => $priority,
        ];
        if ($newTimestamp) {
            $toSet['created'] = new \MongoDate();
        }

        //using upsert because if no documents found then the doc was removed (SHOULD ONLY HAPPEN BY SOMEONE MANUALLY)
        //so we can just send
        $this->collection->update(['_id' => $id], ['$set' => $toSet], ['upsert' => true]);
    }

    /**
     * Requeue message to the queue. Same as ackSend() with the same message.
     *
     * @param array $message message received from get().
     * @param int $earliestGet earliest unix timestamp the message can be retreived.
     * @param float $priority priority for order out of get(). 0 is higher priority than 1
     * @param bool $newTimestamp true to give the payload a new timestamp or false to use given message timestamp
     *
     * @return void
     *
     * @throws \InvalidArgumentException $message does not have a field "id" that is a MongoId
     * @throws \InvalidArgumentException $earliestGet was not an int
     * @throws \InvalidArgumentException $priority was not a float
     * @throws \InvalidArgumentException priority is NaN
     * @throws \InvalidArgumentException $newTimestamp was not a bool
     */
    public function requeue(array $message, $earliestGet = 0, $priority = 0.0, $newTimestamp = true)
    {
        $forRequeue = $message;
        unset($forRequeue['id']);
        $this->ackSend($message, $forRequeue, $earliestGet, $priority, $newTimestamp);
    }

    /**
     * Send a message to the queue.
     *
     * @param array $payload the data to store in the message. Data is handled same way as \MongoCollection::insert()
     * @param int $earliestGet earliest unix timestamp the message can be retreived.
     * @param float $priority priority for order out of get(). 0 is higher priority than 1
     *
     * @return void
     *
     * @throws \InvalidArgumentException $earliestGet was not an int
     * @throws \InvalidArgumentException $priority was not a float
     * @throws \InvalidArgumentException $priority is NaN
     */
    public function send(array $payload, $earliestGet = 0, $priority = 0.0)
    {
        if (!is_int($earliestGet)) {
            throw new \InvalidArgumentException('$earliestGet was not an int');
        }

        if (!is_float($priority)) {
            throw new \InvalidArgumentException('$priority was not a float');
        }

        if (is_nan($priority)) {
            throw new \InvalidArgumentException('$priority was NaN');
        }

        //Ensure $earliestGet is between 0 and MONGO_INT32_MAX
        $earliestGet = min(max(0, $earliestGet), self::MONGO_INT32_MAX);

        $message = [
            'payload' => $payload,
            'running' => false,
            'resetTimestamp' => new \MongoDate(self::MONGO_INT32_MAX),
            'earliestGet' => new \MongoDate($earliestGet),
            'priority' => $priority,
            'created' => new \MongoDate(),
        ];

        $this->collection->insert($message);
    }

    /**
     * Ensure index of correct specification and a unique name whether the specification or name already exist or not.
     * Will not create index if $index is a prefix of an existing index
     *
     * @param array $index index to create in same format as \MongoCollection::ensureIndex()
     *
     * @return void
     *
     * @throws \Exception couldnt create index after 5 attempts
     */
    private function ensureIndex(array $index)
    {
        //if $index is a prefix of any existing index we are good
        foreach ($this->collection->getIndexInfo() as $existingIndex) {
            $slice = array_slice($existingIndex['key'], 0, count($index), true);
            if ($slice === $index) {
                return;
            }
        }

        for ($i = 0; $i < 5; ++$i) {
            for ($name = uniqid(); strlen($name) > 0; $name = substr($name, 0, -1)) {
                //creating an index with same name and different spec does nothing.
                //creating an index with same spec and different name does nothing.
                //so we use any generated name, and then find the right spec after we have called,
                //and just go with that name.
                try {
                    $this->collection->ensureIndex($index, ['name' => $name, 'background' => true]);
                } catch (\MongoException $e) {
                    //this happens when the name was too long, let continue
                }

                foreach ($this->collection->getIndexInfo() as $existingIndex) {
                    if ($existingIndex['key'] === $index) {
                        return;
                    }
                }
            }
        }

        throw new \Exception('couldnt create index after 5 attempts');
    }

    /**
     * Helper method to validate keys and values for the given sort array
     *
     * @param array  $sort             The proposed sort for a mongo index.
     * @param string $label            The name of the variable given to the public ensureXIndex method.
     * @param array  &$completedFields The final index array with payload. prefix added to fields.
     *
     * @return void
     */
    private static function verifySort(array $sort, $label, &$completeFields)
    {
        foreach ($sort as $key => $value) {
            if (!is_string($key)) {
                throw new \InvalidArgumentException("key in \${$label} was not a string");
            }

            if ($value !== 1 && $value !== -1) {
                throw new \InvalidArgumentException(
                    "value of \${$label} is not 1 or -1 for ascending and descending"
                );
            }

            $completeFields["payload.{$key}"] = $value;
        }
    }

    /**
     * Helper method to validate get queries.
     *
     * @param array $query The user provided query.
     * @param array &$completeQuery The validated query for gets.
     *
     * @return void
     */
    private static function verifyQuery(array $query, array &$completeQuery)
    {
        foreach ($query as $key => $value) {
            if (!is_string($key)) {
                throw new \InvalidArgumentException('key in $query was not a string');
            }

            $completeQuery["payload.{$key}"] = $value;
        }
    }
}