Enrich log with traces with mixin feature

Author: erickhun

bufflog.ts

@@ -1,3 +1,5 @@
+import tracer from "dd-trace";
+import formats from "dd-trace/ext/formats";
 
 export class BuffLog {
     pinoLogger: any;
@@ -12,8 +14,20 @@ 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
             customLevels: {