refactor: only convert monotonic to wall upon export

src/custom-otlp-trace-exporter.ts

@@ -0,0 +1,36 @@
+import {
+    addHrTimes,
+    millisToHrTime,
+    OTLPTraceExporter,
+    ReadableSpan,
+} from '../deps.ts';
+
+const LIMIT = new Date('2000-01-01').getTime() / 1000;
+const isMonotonicHrTime = (hrTime: [number, number]): boolean =>
+    hrTime[0] < LIMIT;
+// @ts-ignore
+const variableTimeOrigin = () => new Date() - performance.now();
+
+export class CustomOTLPTraceExporter extends OTLPTraceExporter {
+    export(spans: ReadableSpan[], resultCallback: (result: any) => void): void {
+        // Current timeOrigin
+        const hrTime = millisToHrTime(variableTimeOrigin());
+        // Just before exporting
+        for (const span of spans) {
+            // Only if the spans were created with the monotonic clock
+            if (!isMonotonicHrTime(span.startTime)) {
+                return;
+            }
+            // Convert the times to wall-clock
+            // @ts-ignore
+            span.startTime = addHrTimes(span.startTime, hrTime);
+            // @ts-ignore
+            span.endTime = addHrTimes(span.endTime, hrTime);
+            for (const event of span.events) {
+                event.time = addHrTimes(event.time, hrTime);
+            }
+        }
+        // And proceed to the regular export
+        return super.export(spans, resultCallback);
+    }
+}

src/main.ts

@@ -4,7 +4,7 @@ import {
     BatchTracedSpanProcessor,
     // ConsoleSpanExporter,
     dotenvLoad,
-    OTLPTraceExporter,
+    // OTLPTraceExporter,
     redis,
     Resource,
     SemanticResourceAttributes,
@@ -16,6 +16,7 @@ import { DenoKvCache } from './cache/deno-kv-cache.ts';
 import { RedisCache } from './cache/redis-cache.ts';
 import { createRequestHandler } from './create-request-handler.ts';
 import { CustomTracerProvider } from './custom-tracer-provider.ts';
+import { CustomOTLPTraceExporter } from './custom-otlp-trace-exporter.ts';
 import { instrumentRequestHandler } from './instrument-request-handler.ts';
 import { TimeSpanProcessor } from './time-span-processor.ts';
 import { sanitizeBasePath, sanitizeUpstreamOrigin } from './utils.ts';
@@ -51,7 +52,7 @@ const provider = new CustomTracerProvider({
         [SemanticResourceAttributes.TELEMETRY_SDK_LANGUAGE]: 'javascript',
     }),
 });
-provider.addSpanProcessor(new TimeSpanProcessor());
+//provider.addSpanProcessor(new TimeSpanProcessor());
 provider.addSpanProcessor(
     new SimpleSpanProcessor(new ServerTimingSpanExporter()),
 );
@@ -73,7 +74,7 @@ if (config.DD_TRACE_ENABLED) {
         // an optional limit on pending requests
         concurrencyLimit: 10,
     };
-    const otlpExporter = new OTLPTraceExporter(collectorOptions);
+    const otlpExporter = new CustomOTLPTraceExporter(collectorOptions);
     const otelProcessor = new BatchTracedSpanProcessor(otlpExporter);
     provider.addSpanProcessor(otelProcessor);
     console.log('OTLP options:', collectorOptions);