feat(mongodb): add db statement serializer config (#626)

plugins/node/opentelemetry-instrumentation-mongodb/README.md

@@ -51,6 +51,7 @@ Mongodb instrumentation has few options available to choose from. You can set th
 | ------- | ---- | ----------- |
 | [`enhancedDatabaseReporting`](https://github.com/open-telemetry/opentelemetry-js/blob/main/packages/opentelemetry-api/src/trace/instrumentation/instrumentation.ts#L91) | `string` | If true, additional information about query parameters and results will be attached (as `attributes`) to spans representing database operations |
 | `responseHook` | `MongoDBInstrumentationExecutionResponseHook` (function) | Function for adding custom attributes from db response |
+| `dbStatementSerializer` | `DbStatementSerializer` (function) | Custom serializer function for the db.statement tag |
 
 ## Useful links
 

plugins/node/opentelemetry-instrumentation-mongodb/src/instrumentation.ts

@@ -153,12 +153,13 @@ export class MongoDBInstrumentation extends InstrumentationBase<
             kind: SpanKind.CLIENT,
           }
         );
+
         instrumentation._populateAttributes(
           span,
           ns,
           server,
           // eslint-disable-next-line @typescript-eslint/no-explicit-any
-          operationName !== 'insert' ? (ops[0] as any) : undefined
+          ops[0] as any
         );
         const patchedCallback = instrumentation._patchEnd(span, resultHandler);
         // handle when options is the callback to send the correct number of args
@@ -408,15 +409,34 @@ export class MongoDBInstrumentation extends InstrumentationBase<
 
     // capture parameters within the query as well if enhancedDatabaseReporting is enabled.
     const commandObj = command.query ?? command.q ?? command;
-    const query =
-      this._config?.enhancedDatabaseReporting === true
-        ? commandObj
-        : Object.keys(commandObj).reduce((obj, key) => {
-            obj[key] = '?';
-            return obj;
-          }, {} as { [key: string]: unknown });
+    const dbStatementSerializer =
+      typeof this._config.dbStatementSerializer === 'function'
+        ? this._config.dbStatementSerializer
+        : this._defaultDbStatementSerializer.bind(this);
+
+    safeExecuteInTheMiddle(
+      () => {
+        const query = dbStatementSerializer(commandObj);
+        span.setAttribute(SemanticAttributes.DB_STATEMENT, query);
+      },
+      err => {
+        if (err) {
+          this._diag.error('Error running dbStatementSerializer hook', err);
+        }
+      },
+      true
+    );
+  }
 
-    span.setAttribute(SemanticAttributes.DB_STATEMENT, JSON.stringify(query));
+  private _defaultDbStatementSerializer(commandObj: Record<string, unknown>) {
+    const enhancedDbReporting = !!this._config?.enhancedDatabaseReporting;
+    const resultObj = enhancedDbReporting
+      ? commandObj
+      : Object.keys(commandObj).reduce((obj, key) => {
+          obj[key] = '?';
+          return obj;
+        }, {} as { [key: string]: unknown });
+    return JSON.stringify(resultObj);
   }
 
   /**

plugins/node/opentelemetry-instrumentation-mongodb/src/types.ts

@@ -21,6 +21,14 @@ export interface MongoDBInstrumentationExecutionResponseHook {
   (span: Span, responseInfo: MongoResponseHookInformation): void;
 }
 
+/**
+ * Function that can be used to serialize db.statement tag
+ * @param cmd - MongoDB command object
+ *
+ * @returns serialized string that will be used as the db.statement attribute.
+ */
+export type DbStatementSerializer = (cmd: Record<string, unknown>) => string;
+
 export interface MongoDBInstrumentationConfig extends InstrumentationConfig {
   /**
    * If true, additional information about query parameters and
@@ -36,6 +44,11 @@ export interface MongoDBInstrumentationConfig extends InstrumentationConfig {
    * @default undefined
    */
   responseHook?: MongoDBInstrumentationExecutionResponseHook;
+
+  /**
+   * Custom serializer function for the db.statement tag
+   */
+  dbStatementSerializer?: DbStatementSerializer;
 }
 
 export type Func<T> = (...args: unknown[]) => T;

plugins/node/opentelemetry-instrumentation-mongodb/test/mongodb.test.ts

@@ -33,6 +33,7 @@ instrumentation.disable();
 
 import * as mongodb from 'mongodb';
 import { assertSpans, accessCollection } from './utils';
+import { SemanticAttributes } from '@opentelemetry/semantic-conventions';
 
 describe('MongoDBInstrumentation', () => {
   function create(config: MongoDBInstrumentationConfig = {}) {
@@ -249,6 +250,96 @@ describe('MongoDBInstrumentation', () => {
     });
   });
 
+  describe('when using enhanced database reporting without db statementSerializer', () => {
+    const key = 'key';
+    const value = 'value';
+    const object = { [key]: value };
+
+    beforeEach(() => {
+      memoryExporter.reset();
+      create({
+        enhancedDatabaseReporting: false,
+      });
+    });
+
+    it('should properly collect db statement (hide attribute values)', done => {
+      const span = provider.getTracer('default').startSpan('insertRootSpan');
+      context.with(trace.setSpan(context.active(), span), () => {
+        collection.insertOne(object).then(() => {
+          span.end();
+          const spans = memoryExporter.getFinishedSpans();
+          const operationName = 'mongodb.insert';
+          assertSpans(spans, operationName, SpanKind.CLIENT, false, false);
+          const mongoSpan = spans.find(s => s.name === operationName);
+          const dbStatement = JSON.parse(
+            mongoSpan!.attributes[SemanticAttributes.DB_STATEMENT] as string
+          );
+          assert.strictEqual(dbStatement[key], '?');
+          done();
+        });
+      });
+    });
+  });
+
+  describe('when specifying a dbStatementSerializer configuration', () => {
+    const key = 'key';
+    const value = 'value';
+    const object = { [key]: value };
+
+    describe('with a valid function', () => {
+      beforeEach(() => {
+        memoryExporter.reset();
+        create({
+          dbStatementSerializer: (commandObj: Record<string, unknown>) => {
+            return JSON.stringify(commandObj);
+          },
+        });
+      });
+
+      it('should properly collect db statement', done => {
+        const span = provider.getTracer('default').startSpan('insertRootSpan');
+        context.with(trace.setSpan(context.active(), span), () => {
+          collection.insertOne(object).then(() => {
+            span.end();
+            const spans = memoryExporter.getFinishedSpans();
+            const operationName = 'mongodb.insert';
+            assertSpans(spans, operationName, SpanKind.CLIENT, false, true);
+            const mongoSpan = spans.find(s => s.name === operationName);
+            const dbStatement = JSON.parse(
+              mongoSpan!.attributes[SemanticAttributes.DB_STATEMENT] as string
+            );
+            assert.strictEqual(dbStatement[key], value);
+            done();
+          });
+        });
+      });
+    });
+
+    describe('with an invalid function', () => {
+      beforeEach(() => {
+        memoryExporter.reset();
+        create({
+          enhancedDatabaseReporting: true,
+          dbStatementSerializer: (_commandObj: Record<string, unknown>) => {
+            throw new Error('something went wrong!');
+          },
+        });
+      });
+
+      it('should not do any harm when throwing an exception', done => {
+        const span = provider.getTracer('default').startSpan('insertRootSpan');
+        context.with(trace.setSpan(context.active(), span), () => {
+          collection.insertOne(object).then(() => {
+            span.end();
+            const spans = memoryExporter.getFinishedSpans();
+            assertSpans(spans, 'mongodb.insert', SpanKind.CLIENT);
+            done();
+          });
+        });
+      });
+    });
+  });
+
   describe('when specifying a responseHook configuration', () => {
     const dataAttributeName = 'mongodb_data';
     beforeEach(() => {

plugins/node/opentelemetry-instrumentation-mongodb/test/utils.ts

@@ -86,9 +86,9 @@ export function assertSpans(
   assert.strictEqual(mongoSpan.status.code, SpanStatusCode.UNSET);
 
   if (isEnhancedDatabaseReportingEnabled) {
-    const dbStatement = mongoSpan.attributes[
-      SemanticAttributes.DB_STATEMENT
-    ] as any;
+    const dbStatement = JSON.parse(
+      mongoSpan.attributes[SemanticAttributes.DB_STATEMENT] as string
+    );
     for (const key in dbStatement) {
       assert.notStrictEqual(dbStatement[key], '?');
     }