feat: added prometheus metrics support

src/common.ts

@@ -59,12 +59,16 @@ export interface ConfigFile {
    * List of hidden routes
    */
   hiddenRoutes: string[];
+  /**
+   * Enables metrics on /metrics route
+   */
+  metrics: boolean;
   /**
    * List of outdated versions
    */
   outdatedVersions: string[];
   /**
-   * Output?! TODO
+   * Path the generated config will be written to
    */
   output: string;
   /**
@@ -93,6 +97,10 @@ export interface TemplateView {
    * Listener
    */
   listener: string;
+  /**
+   * Local server with listener for /metrics route
+   */
+  metrics: string;
   /**
    * Allow list for rate limiting
    */

src/main.ts

@@ -241,6 +241,16 @@ ${protocolHardeningParameters}
   return listener;
 }
 
+/**
+ * Reads predefined server entry with metrics location
+ */
+export async function generateMetricsServer(enableMetrics: boolean): Promise<string> {
+  if (!enableMetrics) {
+    return '';
+  }
+  return asyncReadFile('./fixtures/metrics.template', 'utf8');
+}
+
 /**
  * Render a mustache template file with given view object
  *
@@ -300,6 +310,7 @@ export async function getTemplateView(containers: Dockerode.ContainerInfo[]): Pr
     ),
     hiddenRoutes: (await Promise.all(hiddenRoutesPromises)).join(''),
     listener: generateListener(configFile.sslFilePaths),
+    metrics: await generateMetricsServer(configFile.metrics),
     rateLimitAllowList: generateRateLimitAllowList(configFile.rateLimitAllowList),
     staticRoute: await renderTemplate(path.join('fixtures', 'staticRoute.template'), {cors}),
     visibleRoutes: (await Promise.all(visibleRoutesPromises)).join(''),