ProcessRegistry::_getEncodedHostname() - Code Metrics - Inspection of "[WIP] Version 3" - traderinteractive/cronus - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Pull Request — master (#14)

by Chad

created 2018-02-22 01:26 UTC

ProcessRegistry::_getEncodedHostname() A

↳ Parent: Project

Complexity

Conditions	1
Paths	1

Size

Total Lines	4
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
dl	0
loc	4
rs	10
c	0
b	0
f	0
cc	1
eloc	2
nc	1
nop	0

<?php
/**
 * Defines the ProcessRegistry class which uses MongoDB as a backend.
 */

namespace TraderInteractive\Cronus;

use MongoDB\BSON\ObjectID;
use MongoDB\Collection;

/**
 * Class that adds/removes from a process registry.
 */
final class ProcessRegistry implements ProcessRegistryInterface
{
    /** example doc:
     * {
     *     '_id': 'a unique id',
     *     'hosts': {
     *         'a hostname' : {
     *             'a pid': expire timestamp,
     *             ...
     *         },
     *         ...
     *     },
     *     'version' => ObjectID(an id),
     * }
     */

    const MONGO_INT32_MAX = 2147483647;//2147483648 can overflow in php mongo without using the MongoInt64

    /**
     * MongoDB collection containing the process information.
     *
     * @var Collection
     */
    private $collection;

    /**
     * @var string
     */
    private $encodedHostName;

    /**
     * @var integer
     */
    private $pid;

    /**
     * Construct a new instance of the registry.
     *
     * @param Collection $collection The MongoDB collection containing the process information.
     */
    public function __construct(Collection $collection)
    {
        $this->collection = $collection;
        $this->encodedHostName = str_replace(['.', '$'], ['_DOT_', '_DOLLAR_'], gethostname());
        $this->pid = getmypid();
    }

    /**
     * Add to process registry. Adds based on $maxGlobalProcesses and $maxHostProcesses after a process registry
     * cleaning.
     *
     * @param ProcessInterface $process The process to add.
     *
     * @return boolean true if the process was added, false if not or there is too much concurrency at the moment.
     */
    public function add(ProcessInterface $process) : bool
    {
        //loop in case the update fails its optimistic concurrency check
        for ($i = 0; $i < 5; ++$i) {
            $this->ensureProcessDocumentExists($process->getName());
            $existing = $this->getExistingProcessDocument($process->getName());
            $replacement = $this->generateReplacementDocument($existing);
            $totalPidCount = $this->getTotalPidCount($replacement);
            $thisHostPids = $replacement['hosts'][$this->encodedHostName] ?? [];
            if ($totalPidCount >= $process->getMaxGlobalProcesses()
                    || count($thisHostPids) >= $process->getMaxHostProcesses()) {
                return false;
            }

            // add our process
            $thisHostPids[$this->pid] = $this->getExpiresSeconds($process->getMinsBeforeExpire());
            $replacement['hosts'][$this->encodedHostName] = $thisHostPids;

            if ($this->updateExistingDocument($existing['_id'], $existing['version'], $replacement)) {
                return true;
            }
        }

        //too much concurrency at the moment, return false to signify not added.
        return false;
    }

    private function updateExistingDocument(string $id, ObjectID $version, array $replacement) : bool
    {
        $status = $this->collection->replaceOne(
            ['_id' => $id, 'version' => $version],
            $replacement,
            ['writeConcern' => new \MongoDB\Driver\WriteConcern(1, 100, true)]
        );

        return $status->getMatchedCount() === 1;
    }

    private function ensureProcessDocumentExists(string $id)
    {
        $this->collection->findOneAndUpdate(
            ['_id' => $id],
            ['$setOnInsert' => ['hosts' => [], 'version' => new ObjectID()]],
            ['upsert' => true]
        );
    }

    private function generateReplacementDocument(array $existing) : array
    {
        $replacement = $existing;
        $replacement['version'] = new ObjectID();

        //clean $replacement based on their pids and expire times
        foreach ($existing['hosts'] as $hostname => $pids) {
            $this->removeExpiredPids($pids, $hostname, $replacement);
            if (empty($replacement['hosts'][$hostname])) {
                unset($replacement['hosts'][$hostname]);
            }
        }

        return $replacement;
    }

    private function getExistingProcessDocument(string $id) : array
    {
        return $this->collection->findOne(
            ['_id' => $id],
            ['typeMap' => ['root' => 'array', 'document' => 'array', 'array' => 'array']]
        );
    }

    private function removeExpiredPids(array $pids, string $hostname, array &$replacement)
    {
        foreach ($pids as $pid => $expires) {
            if ($this->canRemovePid($hostname, $pid, $expires)) {
                unset($replacement['hosts'][$hostname][$pid]);
            }
        }
    }

    private function canRemovePid(string $hostname, int $pid, int $expires) : bool
    {
        return (($hostname === $this->encodedHostName && !file_exists("/proc/{$pid}"))
                || time() > $expires
                || ($hostname === $this->encodedHostName && $pid === $this->pid));
    }

    private function getTotalPidCount(array $document) : int
    {
        $totalPidCount = 0;
        foreach ($document['hosts'] as $hostname => $pids) {
            $totalPidCount += count($pids);
        }

        return $totalPidCount;
    }

    private function getExpiresSeconds(int $minsBeforeExpire) : int
    {
         $expireSecs = time() + $minsBeforeExpire * 60;
         //ensure expireSecs is between 0 and self::MONGO_INT32_MAX
         return max(0, min($expireSecs, self::MONGO_INT32_MAX));
    }

    /**
     * Removes from process registry. Does not do anything needed for use of the add() method. Most will only use at the
     * end of their script so the mongo collection is up to date.
     *
     * @param ProcessInterface $process The process to remove.
     *
     * @return void
     */
    public function remove(ProcessInterface $process)
    {
        $this->collection->updateOne(
            ['_id' => $process->getName()],
            ['$unset' => ["hosts.{$this->encodedHostName}.{$this->pid}" => ''], '$set' => ['version' => new ObjectID()]]
        );
    }

    /**
     * Reset a process expire time in the registry.
     *
     * @param ProcessInterface $process The process to reset.
     *
     * @return void
     */
    public function reset(ProcessInterface $process)
    {
        $expireSecs = time() + $process->getMinsBeforeExpire() * 60;
        //ensure expireSecs is between 0 and self::MONGO_INT32_MAX
        $expireSecs = max(0, min($expireSecs, self::MONGO_INT32_MAX));

        $this->collection->updateOne(
            ['_id' => $process->getName()],
            [
                '$set' => [
                    "hosts.{$this->encodedHostName}.{$this->pid}" => $expireSecs,
                    'version' => new ObjectID(),
                ],
            ]
        );
    }
}


1			<?php
2			/**
3			* Defines the ProcessRegistry class which uses MongoDB as a backend.
4			*/
5
6			namespace TraderInteractive\Cronus;
7
8			use MongoDB\BSON\ObjectID;
9			use MongoDB\Collection;
10
11			/**
12			* Class that adds/removes from a process registry.
13			*/
14			final class ProcessRegistry implements ProcessRegistryInterface
15			{
16			/** example doc:
17			* {
18			* '_id': 'a unique id',
19			* 'hosts': {
20			* 'a hostname' : {
21			* 'a pid': expire timestamp,
22			* ...
23			* },
24			* ...
25			* },
26			* 'version' => ObjectID(an id),
27			* }
28			*/
29
30			const MONGO_INT32_MAX = 2147483647;//2147483648 can overflow in php mongo without using the MongoInt64
31
32			/**
33			* MongoDB collection containing the process information.
34			*
35			* @var Collection
36			*/
37			private $collection;
38
39			/**
40			* @var string
41			*/
42			private $encodedHostName;
43
44			/**
45			* @var integer
46			*/
47			private $pid;
48
49			/**
50			* Construct a new instance of the registry.
51			*
52			* @param Collection $collection The MongoDB collection containing the process information.
53			*/
54			public function __construct(Collection $collection)
55			{
56			$this->collection = $collection;
57			$this->encodedHostName = str_replace(['.', '$'], ['_DOT_', '_DOLLAR_'], gethostname());
58			$this->pid = getmypid();
59			}
60
61			/**
62			* Add to process registry. Adds based on $maxGlobalProcesses and $maxHostProcesses after a process registry
63			* cleaning.
64			*
65			* @param ProcessInterface $process The process to add.
66			*
67			* @return boolean true if the process was added, false if not or there is too much concurrency at the moment.
68			*/
69			public function add(ProcessInterface $process) : bool
70			{
71			//loop in case the update fails its optimistic concurrency check
72			for ($i = 0; $i < 5; ++$i) {
73			$this->ensureProcessDocumentExists($process->getName());
74			$existing = $this->getExistingProcessDocument($process->getName());
75			$replacement = $this->generateReplacementDocument($existing);
76			$totalPidCount = $this->getTotalPidCount($replacement);
77			$thisHostPids = $replacement['hosts'][$this->encodedHostName] ?? [];
78			if ($totalPidCount >= $process->getMaxGlobalProcesses()
79			\|\| count($thisHostPids) >= $process->getMaxHostProcesses()) {
80			return false;
81			}
82
83			// add our process
84			$thisHostPids[$this->pid] = $this->getExpiresSeconds($process->getMinsBeforeExpire());
85			$replacement['hosts'][$this->encodedHostName] = $thisHostPids;
86
87			if ($this->updateExistingDocument($existing['_id'], $existing['version'], $replacement)) {
88			return true;
89			}
90			}
91
92			//too much concurrency at the moment, return false to signify not added.
93			return false;
94			}
95
96			private function updateExistingDocument(string $id, ObjectID $version, array $replacement) : bool
97			{
98			$status = $this->collection->replaceOne(
99			['_id' => $id, 'version' => $version],
100			$replacement,
101			['writeConcern' => new \MongoDB\Driver\WriteConcern(1, 100, true)]
102			);
103
104			return $status->getMatchedCount() === 1;
105			}
106
107			private function ensureProcessDocumentExists(string $id)
108			{
109			$this->collection->findOneAndUpdate(
110			['_id' => $id],
111			['$setOnInsert' => ['hosts' => [], 'version' => new ObjectID()]],
112			['upsert' => true]
113			);
114			}
115
116			private function generateReplacementDocument(array $existing) : array
117			{
118			$replacement = $existing;
119			$replacement['version'] = new ObjectID();
120
121			//clean $replacement based on their pids and expire times
122			foreach ($existing['hosts'] as $hostname => $pids) {
123			$this->removeExpiredPids($pids, $hostname, $replacement);
124			if (empty($replacement['hosts'][$hostname])) {
125			unset($replacement['hosts'][$hostname]);
126			}
127			}
128
129			return $replacement;
130			}
131
132			private function getExistingProcessDocument(string $id) : array
133			{
134			return $this->collection->findOne(
135			['_id' => $id],
136			['typeMap' => ['root' => 'array', 'document' => 'array', 'array' => 'array']]
137			);
138			}
139
140			private function removeExpiredPids(array $pids, string $hostname, array &$replacement)
141			{
142			foreach ($pids as $pid => $expires) {
143			if ($this->canRemovePid($hostname, $pid, $expires)) {
144			unset($replacement['hosts'][$hostname][$pid]);
145			}
146			}
147			}
148
149			private function canRemovePid(string $hostname, int $pid, int $expires) : bool
150			{
151			return (($hostname === $this->encodedHostName && !file_exists("/proc/{$pid}"))
152			\|\| time() > $expires
153			\|\| ($hostname === $this->encodedHostName && $pid === $this->pid));
154			}
155
156			private function getTotalPidCount(array $document) : int
157			{
158			$totalPidCount = 0;
159			foreach ($document['hosts'] as $hostname => $pids) {
160			$totalPidCount += count($pids);
161			}
162
163			return $totalPidCount;
164			}
165
166			private function getExpiresSeconds(int $minsBeforeExpire) : int
167			{
168			$expireSecs = time() + $minsBeforeExpire * 60;
169			//ensure expireSecs is between 0 and self::MONGO_INT32_MAX
170			return max(0, min($expireSecs, self::MONGO_INT32_MAX));
171			}
172
173			/**
174			* Removes from process registry. Does not do anything needed for use of the add() method. Most will only use at the
175			* end of their script so the mongo collection is up to date.
176			*
177			* @param ProcessInterface $process The process to remove.
178			*
179			* @return void
180			*/
181			public function remove(ProcessInterface $process)
182			{
183			$this->collection->updateOne(
184			['_id' => $process->getName()],
185			['$unset' => ["hosts.{$this->encodedHostName}.{$this->pid}" => ''], '$set' => ['version' => new ObjectID()]]
186			);
187			}
188
189			/**
190			* Reset a process expire time in the registry.
191			*
192			* @param ProcessInterface $process The process to reset.
193			*
194			* @return void
195			*/
196			public function reset(ProcessInterface $process)
197			{
198			$expireSecs = time() + $process->getMinsBeforeExpire() * 60;
199			//ensure expireSecs is between 0 and self::MONGO_INT32_MAX
200			$expireSecs = max(0, min($expireSecs, self::MONGO_INT32_MAX));
201
202			$this->collection->updateOne(
203			['_id' => $process->getName()],
204			[
205			'$set' => [
206			"hosts.{$this->encodedHostName}.{$this->pid}" => $expireSecs,
207			'version' => new ObjectID(),
208			],
209			]
210			);
211			}
212			}
213

traderinteractive / cronus

Pull Request — master (#14)

ProcessRegistry::_getEncodedHostname() A

Complexity

Size

Duplication

Importance

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