fix(exporter-prometheus): add appendTimestamp option to ExporterConfig

Signed-off-by: Antonio Franco <antoniomrfranco@gmail.com>

packages/opentelemetry-exporter-prometheus/src/PrometheusExporter.ts

@@ -33,13 +33,15 @@ export class PrometheusExporter implements MetricExporter {
     port: 9464,
     endpoint: '/metrics',
     prefix: '',
+    appendTimestamp: true,
   };
 
   private readonly _logger: api.Logger;
   private readonly _port: number;
   private readonly _endpoint: string;
   private readonly _server: Server;
   private readonly _prefix?: string;
+  private readonly _appendTimestamp?: boolean;
   private _serializer: PrometheusSerializer;
   private _batcher = new PrometheusLabelsBatcher();
 
@@ -56,8 +58,9 @@ export class PrometheusExporter implements MetricExporter {
     this._logger = config.logger || new NoopLogger();
     this._port = config.port || PrometheusExporter.DEFAULT_OPTIONS.port;
     this._prefix = config.prefix || PrometheusExporter.DEFAULT_OPTIONS.prefix;
+    this._appendTimestamp = config.appendTimestamp ?? PrometheusExporter.DEFAULT_OPTIONS.appendTimestamp;
     this._server = createServer(this._requestHandler);
-    this._serializer = new PrometheusSerializer(this._prefix);
+    this._serializer = new PrometheusSerializer(this._prefix, this._appendTimestamp);
 
     this._endpoint = (
       config.endpoint || PrometheusExporter.DEFAULT_OPTIONS.endpoint

packages/opentelemetry-exporter-prometheus/src/export/types.ts

@@ -27,6 +27,12 @@ export interface ExporterConfig {
    * */
   prefix?: string;
 
+  /**
+   * Append timestamp to metrics
+   * @default true
+   */
+  appendTimestamp?: boolean;
+
   /**
    * Endpoint the metrics should be exposed at with preceding slash
    * @default '/metrics'