observability: ensure that each span has otel.scope.name,version (#2105)

* observability: ensure that each span has otel.scope.name,version

This change ensures that each span created by the code in this
library is annotated with:
* otel.scope.name = "cloud.google.com/nodejs/spanner"
* otel.scope.version = <LIBRARY_VERSION>

Updates #2079

* Address review feedback to use TRACER_* not LIB_*

Author: odeke-em

observability-test/observability.ts

@@ -25,13 +25,17 @@ const {SpanStatusCode, TracerProvider} = require('@opentelemetry/api');
 // eslint-disable-next-line n/no-extraneous-require
 const {SimpleSpanProcessor} = require('@opentelemetry/sdk-trace-base');
 const {
+  TRACER_NAME,
+  TRACER_VERSION,
   SPAN_NAMESPACE_PREFIX,
   getActiveOrNoopSpan,
   setSpanError,
   setSpanErrorAndException,
   startTrace,
 } = require('../src/instrument');
 const {
+  ATTR_OTEL_SCOPE_NAME,
+  ATTR_OTEL_SCOPE_VERSION,
   SEMATTRS_DB_NAME,
   SEMATTRS_DB_SQL_TABLE,
   SEMATTRS_DB_STATEMENT,
@@ -129,6 +133,18 @@ describe('startTrace', () => {
   it('with semantic attributes', () => {
     const opts = {tableName: 'table', dbName: 'db'};
     startTrace('aSpan', opts, span => {
+      assert.equal(
+        span.attributes[ATTR_OTEL_SCOPE_NAME],
+        TRACER_NAME,
+        'Missing OTEL_SCOPE_NAME attribute'
+      );
+
+      assert.equal(
+        span.attributes[ATTR_OTEL_SCOPE_VERSION],
+        TRACER_VERSION,
+        'Missing OTEL_SCOPE_VERSION attribute'
+      );
+
       assert.equal(
         span.attributes[SEMATTRS_DB_SYSTEM],
         'spanner',

src/instrument.ts

@@ -15,6 +15,8 @@
  */
 
 import {
+  ATTR_OTEL_SCOPE_NAME,
+  ATTR_OTEL_SCOPE_VERSION,
   SEMATTRS_DB_NAME,
   SEMATTRS_DB_STATEMENT,
   SEMATTRS_DB_SYSTEM,
@@ -53,6 +55,8 @@ export type {observabilityOptions as ObservabilityOptions};
 const TRACER_NAME = 'cloud.google.com/nodejs/spanner';
 const TRACER_VERSION = '7.14.0'; // Manually hard coded, TODO: remove
 
+export {TRACER_NAME, TRACER_VERSION}; // Only exported for testing.
+
 /**
  * getTracer fetches the tracer from the provided tracerProvider.
  * @param {TracerProvider} [tracerProvider] optional custom tracer provider
@@ -102,6 +106,8 @@ export function startTrace<T>(
     {kind: SpanKind.CLIENT},
     span => {
       span.setAttribute(SEMATTRS_DB_SYSTEM, 'spanner');
+      span.setAttribute(ATTR_OTEL_SCOPE_NAME, TRACER_NAME);
+      span.setAttribute(ATTR_OTEL_SCOPE_VERSION, TRACER_VERSION);
 
       if (config.tableName) {
         span.setAttribute(SEMATTRS_DB_SQL_TABLE, config.tableName);