A prometheus client library written in PHP

This library uses Redis or APCu to do the client side aggregation. If using Redis, we recommend to run a local Redis instance next to your PHP workers.

How does it work?

Usually PHP worker processes don't share any state. You can pick from three adapters. Redis, APC or an in memory adapter. While the first needs a separate binary running, the second just needs the APC extension to be installed. If you don't need persistent metrics between requests (e.g. a long running cron job or script) the in memory adapter might be suitable to use.

Installation

Install via Composer:

composer require tuleap/prometheus-client

Usage

A simple counter:

$storage = new \Enalean\Prometheus\Storage\InMemoryStore();
(new \Enalean\Prometheus\Registry\CollectorRegistry($storage))
    ->getOrRegisterCounter(\Enalean\Prometheus\Value\MetricName::fromName('some_quick_counter'), 'just a quick measurement')
    ->inc();

Write some enhanced metrics:

$storage = new \Enalean\Prometheus\Storage\InMemoryStore();
$registry = new \Enalean\Prometheus\Registry\CollectorRegistry($storage);

$counter = $registry->getOrRegisterCounter(
    \Enalean\Prometheus\Value\MetricName::fromNamespacedName('test', 'some_counter'),
    'it increases',
    \Enalean\Prometheus\Value\MetricLabelNames::fromNames('type')
);
$counter->incBy(3, 'blue');

$gauge = $registry->getOrRegisterGauge(
    \Enalean\Prometheus\Value\MetricName::fromNamespacedName('test', 'some_gauge'),
    'it sets',
    \Enalean\Prometheus\Value\MetricLabelNames::fromNames('type')
);
$gauge->set(2.5, 'blue');

$histogram = $registry->getOrRegisterHistogram(
    \Enalean\Prometheus\Value\MetricName::fromNamespacedName('test', 'some_histogram'),
    'it observes',
    \Enalean\Prometheus\Value\HistogramLabelNames::fromNames('type'),
    [0.1, 1, 2, 3.5, 4, 5, 6, 7, 8, 9]
);
$histogram->observe(3.5, 'blue');

Manually register and retrieve metrics (these steps are combined in the getOrRegister... methods):

$storage = new \Enalean\Prometheus\Storage\InMemoryStore();
$registry = new \Enalean\Prometheus\Registry\CollectorRegistry($storage);

$counterA = $registry->registerCounter(
    \Enalean\Prometheus\Value\MetricName::fromNamespacedName('test', 'some_counter'),
    'it increases',
    \Enalean\Prometheus\Value\MetricLabelNames::fromNames('type')
);
$counterA->incBy(3, 'blue');

// once a metric is registered, it can be retrieved using e.g. getCounter:
$counterB = $registry->getCounter(\Enalean\Prometheus\Value\MetricName::fromNamespacedName('test', 'some_counter'));
$counterB->incBy(2, 'red');

Expose the metrics:

$storage = new \Enalean\Prometheus\Storage\InMemoryStore();
$registry = new \Enalean\Prometheus\Registry\CollectorRegistry($storage);

$renderer = new \Enalean\Prometheus\Renderer\RenderTextFormat();

header('Content-type: ' . $renderer->getMimeType());
echo $renderer->render($registry->getMetricFamilySamples());

Using the Redis storage:

$redis = new \Redis();
$redis->connect('127.0.0.1', 6379);
$storage = new \Enalean\Prometheus\Storage\RedisStore($redis);
$registry = new \Enalean\Prometheus\Registry\CollectorRegistry($storage);

$counter = $registry->registerCounter(
    \Enalean\Prometheus\Value\MetricName::fromNamespacedName('test', 'some_counter'),
    'it increases',
    \Enalean\Prometheus\Value\MetricLabelNames::fromNames('type')
);
$counter->incBy(3, 'blue');

$renderer = new \Enalean\Prometheus\Renderer\RenderTextFormat();
$result = $renderer->render($registry->getMetricFamilySamples());

Using the APCu storage:

$storage = new \Enalean\Prometheus\Storage\APCUStore();
$registry = new \Enalean\Prometheus\Registry\CollectorRegistry($storage);

$counter = $registry->registerCounter(
    \Enalean\Prometheus\Value\MetricName::fromNamespacedName('test', 'some_counter'),
    'it increases',
    \Enalean\Prometheus\Value\MetricLabelNames::fromNames('type')
);
$counter->incBy(3, 'blue');

$renderer = new \Enalean\Prometheus\Renderer\RenderTextFormat();
$result = $renderer->render($registry->getMetricFamilySamples());

Also look at the examples.

Development

Dependencies

• PHP 7.3+
• PHP Redis extension
• PHP APCu extension
• Composer
• Redis

Start a Redis instance:

docker-compose up redis

Tests

Run the tests:

composer install

# when Redis is not listening on localhost:
# export REDIS_HOST=192.168.59.100
./vendor/bin/phpunit
# You might need to enable APCu on the CLI
php -d apc.enable_cli=1 vendor/bin/phpunit

Run the tests with mutation testing:

# when Redis is not listening on localhost:
# export REDIS_HOST=192.168.59.100
./vendor/bin/infection --initial-tests-php-options="-d apc.enable_cli=1"

Run the static analysis:

vendor/bin/psalm

Check conformance with the coding standards:

vendor/bin/phpcs

Black box testing

Just start the nginx, fpm & Redis setup with docker-compose:

docker-compose up

Pick the adapter you want to test.

docker-compose exec phpunit env ADAPTER=apcu vendor/bin/phpunit --testsuite=functionnal
docker-compose exec phpunit env ADAPTER=redis vendor/bin/phpunit --testsuite=functionnal

Acknowledgment

This library is based on the work done on Jimdo/prometheus_client_php.