feat: integrate Monolog for enhanced logging across providers and controller

src/Controller/GraphController.php

@@ -39,18 +39,24 @@ class GraphController
     public function graph(Request $request): Response
     {
         if ($this->allowedHosts !== [] && !in_array($request->getHost(), $this->allowedHosts, true)) {
+            $this->logger->warning('GraphController: rejected request from disallowed host', ['host' => $request->getHost()]);
+
             return new Response('Forbidden', 403);
         }
 
         $theme    = $request->query->get('theme', 'dark');
         $cacheKey = 'graph_' . $theme;
 
-        $svg = $this->cache->get($cacheKey, function (ItemInterface $item) use ($theme): string {
+        $cacheMiss = false;
+        $svg = $this->cache->get($cacheKey, function (ItemInterface $item) use ($theme, &$cacheMiss): string {
+            $cacheMiss = true;
             $item->expiresAfter(3600);
 
             return $this->renderer->render($this->fetchAllContributions(), $theme);
         });
 
+        $this->logger->debug('GraphController: cache ' . ($cacheMiss ? 'miss' : 'hit'), ['theme' => $theme]);
+
         return new Response($svg, 200, [
             'Content-Type'  => 'image/svg+xml',
             'Cache-Control' => 'public, max-age=3600',
@@ -86,7 +92,7 @@ class GraphController
             try {
                 $contributions = $this->merge($contributions, $provider->fetch());
             } catch (\Throwable $e) {
-                $this->logger->warning(sprintf('%s fetch failed: %s', $provider::class, $e->getMessage()));
+                $this->logger->warning(sprintf('%s fetch failed: %s', $provider::class, $e->getMessage()), ['exception' => $e]);
             }
         }