<?php
namespace app\middleware;


use think\facade\Cache;
use think\facade\Request;


class MetricsMiddleware
{
    public function handle($request, \Closure $next)
    {
        $startTime = microtime(true);
        $response = $next($request);


        Cache::inc('http_requests_total');


        $method = $request->method();
        $path = $request->pathinfo();
        $key = "http_requests_by_path{method=\"$method\",path=\"$path\"}";
        Cache::inc($key);


        $responseTime = round(microtime(true) - $startTime, 4);
        Cache::set("http_response_time{path=\"$path\"}", $responseTime);


        $costTime = ($startTime - $_SERVER['REQUEST_TIME_FLOAT']) * 1000;
        Cache::set("http_consumer_cost_time",$costTime);


        return $response;
    }
}

<?php
namespace app\controller;


use think\facade\Cache;
use think\Response;


class Metrics
{
    public function index()
    {
        $metrics = $this->collectMetrics();
        return Response::create($metrics, 'html')
            ->header(['Content-Type' => 'text/plain; charset=utf-8']);
    }


    private function collectMetrics()
    {
        $totalRequests = Cache::get('http_requests_total', 0);
        $onlineUsers = rand(50, 200); 
        $startTime = Cache::remember('app_start_time', function () {
            return time();
        }, 86400);


        $pathMethodMetrics = $this->getHttpRequestsByPath();
        $responseTimeMetrics = $this->getHttpResponseTime();
        $consumerCostTime = Cache::get('http_consumer_cost_time', 0);


        $metrics = <<<METRICS
# HELP http_requests_total 应用总请求数
# TYPE http_requests_total counter
http_requests_total $totalRequests


# HELP online_users 当前在线用户数
# TYPE online_users gauge
online_users $onlineUsers


# HELP app_start_time_seconds 应用启动时间（Unix时间戳）
# TYPE app_start_time_seconds gauge
app_start_time_seconds $startTime


{$pathMethodMetrics}


{$responseTimeMetrics}


# HELP http_consumer_cost_time 请求从到达至响应完成的总耗时（毫秒）
# TYPE http_consumer_cost_time gauge
http_consumer_cost_time $consumerCostTime
METRICS;


        return $metrics;
    }


    /**
     * 处理按路径和方法统计的请求数指标
     */
    private function getHttpRequestsByPath()
    {
        $keys = Cache::handler()->keys('http_requests_by_path*');
        $metrics = [];


        $metrics[] = "# HELP http_requests_by_path 按请求方法和路径统计的请求数";
        $metrics[] = "# TYPE http_requests_by_path counter";


        foreach ($keys as $key) {
            if (preg_match('/http_requests_by_path\{method="([^"]+)",path="([^"]+)"\}/', $key, $matches)) {
                $method = $matches[1]; 
                $path = $matches[2];  
                $value = Cache::get($key, 0); 
                $metrics[] = "http_requests_by_path{method=\"{$method}\",path=\"{$path}\"} {$value}";
            }
        }


        return implode("\n", $metrics);
    }


    /**
     * 处理按路径的响应时间指标
     */
    private function getHttpResponseTime()
    {
        $keys = Cache::handler()->keys('http_response_time*');
        $metrics = [];


        $metrics[] = "# HELP http_response_time 按路径统计的响应时间（秒，保留4位小数）";
        $metrics[] = "# TYPE http_response_time gauge";


        foreach ($keys as $key) {
            if (preg_match('/http_response_time\{path="([^"]+)"\}/', $key, $matches)) {
                $path = $matches[1]; 
                $value = Cache::get($key, 0); 
                $metrics[] = "http_response_time{path=\"{$path}\"} {$value}";
            }
        }


        return implode("\n", $metrics);
    }
}