Use http keep-alive in collector exporter

packages/opentelemetry-exporter-collector/src/platform/node/CollectorExporterNodeBase.ts

@@ -33,13 +33,17 @@ export abstract class CollectorExporterNodeBase<
 > {
   DEFAULT_HEADERS: Record<string, string> = {};
   headers: Record<string, string>;
+  keepAlive: boolean = false;
   constructor(config: CollectorExporterConfigBase = {}) {
     super(config);
     if ((config as any).metadata) {
       this.logger.warn('Metadata cannot be set when using http');
     }
     this.headers =
       parseHeaders(config.headers, this.logger) || this.DEFAULT_HEADERS;
+    if (config.keepAlive) {
+      this.keepAlive = true;
+    }
   }
 
   onInit(_config: CollectorExporterConfigBase): void {

packages/opentelemetry-exporter-collector/src/platform/node/util.ts

@@ -36,7 +36,7 @@ export function sendWithHttp<ExportItem, ServiceRequest>(
 ): void {
   const parsedUrl = new url.URL(collector.url);
 
-  const options = {
+  const options: http.RequestOptions | https.RequestOptions = {
     hostname: parsedUrl.hostname,
     port: parsedUrl.port,
     path: parsedUrl.pathname,
@@ -49,6 +49,12 @@ export function sendWithHttp<ExportItem, ServiceRequest>(
   };
 
   const request = parsedUrl.protocol === 'http:' ? http.request : https.request;
+  const Agent = parsedUrl.protocol === 'http:' ? http.Agent : https.Agent;
+  if (collector.keepAlive) {
+    const keepAliveAgent = new Agent({ keepAlive: true });
+    options.agent = keepAliveAgent;
+  }
+
   const req = request(options, (res: http.IncomingMessage) => {
     if (res.statusCode && res.statusCode < 299) {
       collector.logger.debug(`statusCode: ${res.statusCode}`);

packages/opentelemetry-exporter-collector/src/types.ts

@@ -339,6 +339,7 @@ export interface CollectorExporterConfigBase {
   serviceName?: string;
   attributes?: Attributes;
   url?: string;
+  keepAlive?: boolean;
 }
 
 /**