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.

What has changed from the original library

Added support for work with any DB numbers in Redis-storage.

In original library all metrics saving in DB number 0 (default DB on connect to Redis). In current library you can set DB number in 'db' options in configuration, example

$redis = new Prometheus\Storage\Redis([
'host' => '127.0.0.1',
'port' => 6379,
'timeout' => 0.1,
'read_timeout' => 10,
'persistent_connections' => false,
'password' => 'your_StronG_Password',
'db' => '2', // this is a new options
]);

How using this fork in your project

Remove original library:

composer remove jimdo/prometheus_client_php

Add this code to your composer.json

    "repositories": [
        {
            "type": "vcs",
            "url": "https://github.com/ihomyak/prometheus_client_php"
        }
    ],

And install this fork by command:

composer require jimdo/prometheus_client_php:v0.9.5

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.

Usage

A simple counter:

\Prometheus\CollectorRegistry::getDefault()
    ->getOrRegisterCounter('', 'some_quick_counter', 'just a quick measurement')
    ->inc();

Write some enhanced metrics:

$registry = \Prometheus\CollectorRegistry::getDefault();

$counter = $registry->getOrRegisterCounter('test', 'some_counter', 'it increases', ['type']);
$counter->incBy(3, ['blue']);

$gauge = $registry->getOrRegisterGauge('test', 'some_gauge', 'it sets', ['type']);
$gauge->set(2.5, ['blue']);

$histogram = $registry->getOrRegisterHistogram('test', 'some_histogram', 'it observes', ['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):

$registry = \Prometheus\CollectorRegistry::getDefault();

$counterA = $registry->registerCounter('test', 'some_counter', 'it increases', ['type']);
$counterA->incBy(3, ['blue']);

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

Expose the metrics:

$registry = \Prometheus\CollectorRegistry::getDefault();

$renderer = new RenderTextFormat();
$result = $renderer->render($registry->getMetricFamilySamples());

header('Content-type: ' . RenderTextFormat::MIME_TYPE);
echo $result;

Change the Redis options (the example shows the defaults):

\Prometheus\Storage\Redis::setDefaultOptions(
    [
        'host' => '127.0.0.1',
        'port' => 6379,
        'password' => null,
        'timeout' => 0.1, // in seconds
        'read_timeout' => 10, // in seconds
        'persistent_connections' => false
    ]
);

Using the InMemory storage:

$registry = new CollectorRegistry(new InMemory());

$counter = $registry->registerCounter('test', 'some_counter', 'it increases', ['type']);
$counter->incBy(3, ['blue']);

$renderer = new RenderTextFormat();
$result = $renderer->render($registry->getMetricFamilySamples());

Also look at the examples.

Development

Dependencies

• PHP 5.6
• PHP Redis extension
• PHP APCu extension
• Composer
• Redis

Start a Redis instance:

docker-compose up Redis

Run the tests:

composer install

# when Redis is not listening on localhost:
# export REDIS_HOST=192.168.59.100
./vendor/bin/phpunit

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 run phpunit env ADAPTER=apc vendor/bin/phpunit tests/Test/
docker-compose run phpunit env ADAPTER=redis vendor/bin/phpunit tests/Test/