feat: propagate trace context to hana via sap passport session context (

#230)

CHANGELOG.md

@@ -4,7 +4,12 @@ All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 The format is based on [Keep a Changelog](http://keepachangelog.com/).
 
-## Version 1.0.2 - tbd
+## Version 1.1.0 - tbd
+
+### Added
+
+- Experimental!: Propagate W3C trace context to SAP HANA via session context `SAP_PASSPORT`
+ - Enable via environment variable `SAP_PASSPORT`
 
 ### Fixed
 
@@ -24,7 +29,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 - Support for SAP Cloud Logging credentials via user-provided service
 - Support for adding `@opentelemetry/instrumentation-runtime-node`
  - `npm add @opentelemetry/instrumentation-runtime-node`
- - to `cds.requires.telemetry.instrumentations`, add:
+ - To `cds.requires.telemetry.instrumentations`, add:
  ```json
  "instrumentation-runtime-node": {
  "class": "RuntimeNodeInstrumentation",

README.md

@@ -438,6 +438,7 @@ Hence, the `hrtime` mode is on by default in development but not in production.
 
 - `NO_TELEMETRY`: Disables the plugin
 - `NO_LOCATE`: Disables function location in tracing
+- `SAP_PASSPORT`: Enables propagating W3C trace context to SAP HANA (experimental!)
 - `OTEL_LOG_LEVEL`: If not specified, the log level of cds logger `telemetry` is used
 - `OTEL_SERVICE_NAME`: If not specified, the name is determined from package.json (defaulting to "CAP Application")
 - `OTEL_SERVICE_VERSION`: If not specified, the version is determined from package.json (defaulting to "1.0.0")

lib/tracing/index.js

@@ -147,6 +147,15 @@ module.exports = resource => {
  cds._telemetry.tracer._active = true
  })
 
+ // clear sap passport for new tx
+ if (process.env.SAP_PASSPORT) {
+ cds.on('served', () => {
+ cds.db?.before('BEGIN', async function () {
+ if (this.dbc?.constructor.name in { HDBDriver: 1, HANAClientDriver: 1 }) this.dbc.set({ SAP_PASSPORT: '' })
+ })
+ })
+ }
+
  /*
  * add tracing
  */

lib/tracing/trace.js

@@ -1,4 +1,5 @@
 const cds = require('@sap/cds')
+const LOG = cds.log('telemetry')
 
 const otel = require('@opentelemetry/api')
 const { SpanKind, SpanStatusCode, ROOT_CONTEXT } = otel
@@ -244,6 +245,36 @@ function trace(name, fn, targetObj, args, options = {}) {
 
  _setAttributes(span, _getDynamicDBAttributes(options, args, parentSpan))
 
+ // SAP Passport
+ if (process.env.SAP_PASSPORT && targetObj.dbc?.constructor.name in { HDBDriver: 1, HANAClientDriver: 1 }) {
+ const { spanId, traceId } = span.spanContext()
+ // prettier-ignore
+ let passport = [
+ /* EYECATCHER */ '2A54482A',
+ /* VERSION */ '03',
+ /* LENGTH */ '00E6',
+ /* TRACELEVEL */ '0000',
+ /* COMPONENTID */ '2020202020202020202020202020202020202020202020202020202020202020',
+ /* SERVICE */ '0000',
+ /* USER */ '2020202020202020202020202020202020202020202020202020202020202020',
+ /* ACTION */ '20202020202020202020202020202020202020202020202020202020202020202020202020202020',
+ /* ACTIONTYPE */ '0000',
+ /* PREVCOMPONENTID */ Buffer.from(span.resource.attributes['service.name'].substr(0, 32).padEnd(32, ' ')).toString('hex'),
+ /* TRANSACTIONID */ Buffer.from(traceId.toUpperCase()).toString('hex'),
+ /* CLIENT */ '202020',
+ /* COMPONENTTYPE */ '0000',
+ /* ROOTCONTEXTID */ traceId.toUpperCase(),
+ /* CONNECTIONID */ '0000000000000001' + spanId.toUpperCase(),
+ /* CONNECTIONCNT */ '00000001',
+ /* VARPARTCOUNT */ '0000',
+ /* VARPARTOFFSET */ '0000', // REVISIT: @sap/dsrpassport uses '0226'
+ /* EYECATCHER */ '2A54482A'
+ ]
+ passport = passport.join('')
+ LOG._debug && LOG.debug('Setting SAP Passport:', passport)
+ targetObj.dbc.set({ SAP_PASSPORT: passport })
+ }
+
  // augment db.statement at parent, if necessary
  if (
  span.attributes[SEMATTRS_DB_STATEMENT] &&