如何将PHP应用数据高效地暴露给Prometheus监控系统，使用previousnext/php-prometheus可以轻松实现

<code class="bash">composer require previousnext/php-prometheus</code>

<pre class="brush:php;toolbar:false;">use PreviousNext\Prometheus\MetricSerializerFactory;

$serializer = MetricSerializerFactory::create();

<pre class="brush:php;toolbar:false;">use PreviousNext\Prometheus\Gauge;

// 创建一个Gauge指标，指定名称、类型和帮助文本
$gauge = new Gauge("my_app", "memory_usage", "Current memory usage of the application in bytes");

// 设置指标值，可以带标签
$gauge->set(1024 * 1024 * 50, ['unit' => 'bytes', 'process' => 'web']); // 50MB
$gauge->set(1024 * 1024 * 45, ['unit' => 'bytes', 'process' => 'cli']); // 45MB
$gauge->set(0); // 也可以不带标签，表示默认实例

// 序列化为Prometheus文本格式
$output = $serializer->serialize($gauge, 'prometheus');

echo $output;

<pre class="brush:php;toolbar:false;"># HELP my_app_memory_usage Current memory usage of the application in bytes
# TYPE my_app_memory_usage gauge
my_app_memory_usage{unit="bytes",process="web"} 52428800
my_app_memory_usage{unit="bytes",process="cli"} 47185920
my_app_memory_usage 0

<pre class="brush:php;toolbar:false;">use PreviousNext\Prometheus\Counter;

// 创建一个Counter指标
$counter = new Counter("my_app", "total_requests", "Total number of requests processed");

// 设置当前累加值，同样可以带标签
$counter->set(12345, ['endpoint' => '/api/v1/users']);
$counter->set(678, ['endpoint' => '/api/v1/health']);

$output = $serializer->serialize($counter, 'prometheus');

echo $output;

<pre class="brush:php;toolbar:false;"># HELP my_app_total_requests Total number of requests processed
# TYPE my_app_total_requests counter
my_app_total_requests{endpoint="/api/v1/users"} 12345
my_app_total_requests{endpoint="/api/v1/health"} 678

<pre class="brush:php;toolbar:false;">use PreviousNext\Prometheus\Summary;

// 创建一个Summary指标，注意这里的'request_duration'是标签的键名
$summary = new Summary("my_app", "request_latency", "Request latency in seconds", 'quantile');

// 设置分位数桶及其对应的值
$buckets = [0, 0.25, 0.5, 0.75, 1]; // 0s, 0.25s, 0.5s, 0.75s, 1s
$values = [2, 4, 6, 8, 10]; // 对应分位数的值
$summary->setValues($buckets, $values);

// 设置总和与总计数
$summary->setSum(543.21); // 总延迟时间
$summary->setCount(212);  // 总请求次数

$output = $serializer->serialize($summary, 'prometheus');

echo $output;

<pre class="brush:php;toolbar:false;"># HELP my_app_request_latency Request latency in seconds
# TYPE my_app_request_latency summary
my_app_request_latency{quantile="0"} 2
my_app_request_latency{quantile="0.25"} 4
my_app_request_latency{quantile="0.5"} 6
my_app_request_latency{quantile="0.75"} 8
my_app_request_latency{quantile="1"} 10
my_app_request_latency_sum 543.21
my_app_request_latency_count 212