From fab34098ca7592abdcaf02f466d2c65a9593b09e Mon Sep 17 00:00:00 2001
From: Alex Bowers <bowersbros@gmail.com>
Date: Tue, 26 Jul 2022 18:16:37 +0100
Subject: [PATCH] Handle metrics for databases

---
 config/metrics.php                            |  9 +++
 src/CloudNativeServiceProvider.php            | 71 +++++++++++++++----
 .../UnsupportedAdapterException.php           |  8 +++
 3 files changed, 73 insertions(+), 15 deletions(-)
 create mode 100644 src/Exceptions/UnsupportedAdapterException.php

diff --git a/config/metrics.php b/config/metrics.php
index 4c0a1e0..6f6f8e5 100644
--- a/config/metrics.php
+++ b/config/metrics.php
@@ -1,6 +1,15 @@
 <?php
 
 return [
+    // Allowed values: 'redis', 'apc', 'apcng', 'memory' (default)
+    'adapter' => env('METRICS_ADAPTER', 'memory'),
+
+    // What metrics do we want to report on?
+    'handle' => [
+        'database' => env('METRICS_HANDLE_DATABASE', true),
+        'http' => env('METRICS_HANDLE_HTTP', true),
+    ],
+
     // The route configuration controls which path the metrics data is served on
     'route' => [
         'enabled' => env('ENABLE_METRICS', true),
diff --git a/src/CloudNativeServiceProvider.php b/src/CloudNativeServiceProvider.php
index b0ab13b..c738613 100644
--- a/src/CloudNativeServiceProvider.php
+++ b/src/CloudNativeServiceProvider.php
@@ -4,35 +4,32 @@
 
 use Illuminate\Contracts\Config\Repository;
 use Illuminate\Contracts\Http\Kernel;
+use Illuminate\Database\Events\QueryExecuted;
 use Illuminate\Routing\Router;
+use Illuminate\Support\Facades\App;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Log;
 use Illuminate\Support\ServiceProvider;
+use Jobilla\CloudNative\Laravel\Exceptions\UnsupportedAdapterException;
 use Jobilla\CloudNative\Laravel\Http\Controllers\ServeMetrics;
 use Jobilla\CloudNative\Laravel\Http\Middleware\RecordPrometheusMetrics;
 use Prometheus\CollectorRegistry;
 use Prometheus\Storage\APC;
+use Prometheus\Storage\APCng;
+use Prometheus\Storage\InMemory;
+use Prometheus\Storage\Redis;
 
 class CloudNativeServiceProvider extends ServiceProvider
 {
+    protected CollectorRegistry $registry;
+
     public function register()
     {
         $this->mergeConfigFrom(__DIR__.'/../config/metrics.php', 'metrics');
-
-        $this->app->singleton(CollectorRegistry::class, function () {
-            return new CollectorRegistry(new APC());
-        });
     }
 
     public function boot(Repository $config, Kernel $kernel)
     {
-        $this->publishes([
-            __DIR__.'/../config/logging.php' => config_path('logging.php'),
-            __DIR__.'/../config/metrics.php' => config_path('metrics.php'),
-        ], 'cloud-native-config');
-
-        $this->publishes([
-            __DIR__.'/../config/logging.php' => config_path('logging.php'),
-        ], 'cloud-native-logging');
-
         $this->publishes([
             __DIR__.'/../config/metrics.php' => config_path('metrics.php'),
         ], 'cloud-native-metrics');
@@ -41,11 +38,55 @@ public function boot(Repository $config, Kernel $kernel)
             __DIR__.'/../assets/Dockerfile' => base_path('Dockerfile'),
         ], 'dockerfile');
 
-        if ($config->get('metrics.route.enabled')) {
+        $this->app->singleton(CollectorRegistry::class, function () use ($config) {
+            $adapter = $config->get('metrics.adapter', 'memory');
+
+            switch ($adapter) {
+                case 'redis':
+                    return new CollectorRegistry(new Redis);
+                break;
+                case 'apc':
+                    if (filter_var(ini_get('apcu.enable_cli'), FILTER_VALIDATE_BOOLEAN) === false && App::runningInConsole()) {
+                        Log::warning('Metrics adapter temporarily turned to "memory" because apc is disabled in CLI. See: https://www.php.net/manual/en/apcu.configuration.php');
+                        return new CollectorRegistry(new InMemory);
+                    }
+
+                    return new CollectorRegistry(new APC);
+                break;
+                case 'apcng':
+                    return new CollectorRegistry(new APCng);
+                break;
+                case 'memory':
+                    return new CollectorRegistry(new InMemory);
+                break;
+                default:
+                    throw new UnsupportedAdapterException("Adapter `{$adapter}` is not supported.");
+                break;
+            }
+        });
+
+        $this->registry = $this->app->make(CollectorRegistry::class);
+
+        if ($this->registry && $config->get('metrics.handle.database')) {
+            DB::listen(function(QueryExecuted $query) use ($config) {
+                $query_labels = ['query' => $query->sql, 'mode' => strtok($query->sql, ' ')];
+
+                $query_counter = $this->registry->getOrRegisterCounter('db', 'query_total', 'Counter of total queries', array_keys($query_labels));
+                $query_counter->inc(array_values($query_labels));
+
+                $query_duration = $this->registry->getOrRegisterHistogram('db', 'query_duration_ms', 'Duration of query', array_keys($query_labels), $config->get('metrics.buckets'));
+                $query_duration->observe($query->time, array_values($query_labels));
+            });
+        }
+
+        if ($this->registry && $config->get('metrics.handle.http')) {
+            $kernel->prependMiddleware(RecordPrometheusMetrics::class);
+        }
+
+        if ($this->registry && $config->get('metrics.route.enabled')) {
             /** @var Router $router */
             $router = $this->app['router'];
             $router->get($config->get('metrics.route.path'), ServeMetrics::class);
-            $kernel->prependMiddleware(RecordPrometheusMetrics::class);
         }
     }
 }
\ No newline at end of file
diff --git a/src/Exceptions/UnsupportedAdapterException.php b/src/Exceptions/UnsupportedAdapterException.php
new file mode 100644
index 0000000..65bb7b5
--- /dev/null
+++ b/src/Exceptions/UnsupportedAdapterException.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Jobilla\CloudNative\Laravel\Exceptions;
+
+class UnsupportedAdapterException extends \Exception
+{
+    
+}
\ No newline at end of file