test: running together with xotel agent

lib/tracing/index.js

@@ -1,8 +1,8 @@
 const cds = require('@sap/cds')
 const LOG = cds.log('telemetry')
 
-const { trace } = require('@opentelemetry/api')
-const { getEnv, getEnvWithoutDefaults } = require('@opentelemetry/core')
+const { trace, SpanKind } = require('@opentelemetry/api')
+const { ExportResultCode, getEnv, getEnvWithoutDefaults } = require('@opentelemetry/core')
 const { Resource } = require('@opentelemetry/resources')
 const { BatchSpanProcessor, SimpleSpanProcessor, SamplingDecision } = require('@opentelemetry/sdk-trace-base')
 const { NodeTracerProvider } = require('@opentelemetry/sdk-trace-node')
@@ -156,6 +156,25 @@ module.exports = resource => {
     LOG._info && LOG.info('Dynatrace OneAgent detected, disabling trace exporter')
   } else {
     const exporter = _getExporter()
+
+    // unofficial hacks for running with xotel agent:
+    // - do not export @opentelemetry/instrumentation-hdb spans
+    // - remove parentSpanId from http spans if there is no traceparent header
+    // - switch SERVER spans back to INTERNAL spans
+    if (cds.env.requires.telemetry._with_xotel) {
+      LOG._info && LOG.info('Adding export mods for running with @sap/xotel-agent-ext-js')
+      const { export: _export } = exporter
+      exporter.export = function (spans, resultCallback) {
+        const _spans = spans.filter(s => s.instrumentationLibrary?.name !== '@opentelemetry/instrumentation-hdb')
+        if (!_spans.length) return resultCallback({ code: ExportResultCode.SUCCESS })
+        for (const _span of _spans) {
+          if (_should_be_orphan(_span)) _make_orphan(_span)
+          if (_should_be_internal(_span)) _make_internal(_span)
+        }
+        return _export.call(this, _spans, resultCallback)
+      }
+    }
+
     const processorConfig = cds.env.requires.telemetry.tracing.processor?.config || {}
     const processor =
       process.env.NODE_ENV === 'production'
@@ -181,3 +200,19 @@ module.exports = resource => {
 
   return tracerProvider
 }
+
+const _should_be_orphan = span =>
+  span.instrumentationLibrary?.name === '@opentelemetry/instrumentation-http' &&
+  span.parentSpanId &&
+  !span.attributes['http.request.header.traceparent']
+const _make_orphan = span => {
+  LOG._debug && LOG.debug('Removing parentSpanId from span:', span.spanContext().spanId)
+  span.parentSpanId = undefined
+}
+
+const _should_be_internal = span =>
+  span.kind === SpanKind.SERVER && span.instrumentationLibrary?.name !== '@opentelemetry/instrumentation-http'
+const _make_internal = span => {
+  LOG._debug && LOG.debug('Switching span kind back to INTERNAL for span:', span.spanContext().spanId)
+  span.kind = SpanKind.INTERNAL
+}

lib/tracing/trace.js

@@ -253,6 +253,12 @@ function trace(req, fn, that, args, opts = {}) {
   if (kind == null) {
     kind = SpanKind.INTERNAL //> default
 
+    // unofficial hack for running with xotel agent: default to SERVER spans
+    if (cds.env.requires.telemetry._with_xotel) {
+      LOG._debug && LOG.debug('Temporaily switching span kind to SERVER to circumvent no sampling decision by xotel')
+      kind = SpanKind.SERVER
+    }
+
     if (that instanceof cds.RemoteService) kind = SpanKind.CLIENT
     else if (that instanceof cds.MessagingService) {
       const msg = cds.env.requires[that.name]