Add datadog tracing support

bufflog.ts

@@ -1,3 +1,5 @@
+import tracer from "dd-trace";
+import formats from "dd-trace/ext/formats";
 
 export class BuffLog {
     pinoLogger: any;
@@ -12,7 +14,19 @@ export class BuffLog {
 
             // Define "base" fields
             // soon: remove the `v` field https://github.com/pinojs/pino/issues/620
-            base: {
+            base: {},
+
+            mixin () {
+                // Check here if a current trace exist to inject it in the log
+                // `tracer` is a singleton, will no-op if no tracer was initialized
+                var span = tracer.scope().active()
+                if (span) {
+                    const traceInfo = {}
+                    tracer.inject(span.context(), formats.LOG, traceInfo);
+                    return traceInfo;
+                } else {
+                    return {}
+                }
             },
 
             // notice doesn't exist in pino, let's add it

index.ts

@@ -1,5 +1,12 @@
+import tracer from "dd-trace";
+import express from 'express';
 import {BuffLog} from './bufflog';
 
+tracer.init({
+    hostname: "dd-agent-hostname",
+    logInjection: false
+});
+
 let logger = new BuffLog();
 
 logger.info('hello info');
@@ -8,3 +15,20 @@ logger.notice('hello notice');
 logger.warning('hello warning');
 logger.error('hello error');
 logger.critical('hello critical');
+
+const app = express();
+
+app.listen(4000, () => {
+    console.log(`Server is listening on port 4000`);
+});
+
+app.get('/', (req, res) =>  {
+    var logger = new BuffLog();
+    logger.notice("Notice log via endpoint");
+    logger.info('hello info');
+    logger.debug('hello debug');
+    logger.notice('hello notice');
+    logger.warning('hello warning');
+    logger.error('hello error');
+    logger.critical('hello critical');
+});