feat(instrumentation-bunyan): Allow log level to be configured for log sending

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

@@ -87,6 +87,7 @@ Log injection can be disabled with the `disableLogCorrelation: true` option.
 | Option                  | Type              | Description |
 | ----------------------- | ----------------- | ----------- |
 | `disableLogSending`     | `boolean`         | Whether to disable [log sending](#log-sending). Default `false`. |
+| `logSeverity`           | `SeverityNumber`  | Control severity level for [log sending](#log-sending). Default `SeverityNumber.UNSPECIFIED`, it will use Bunnyan Logger's current level when unspecified. |
 | `disableLogCorrelation` | `boolean`         | Whether to disable [log correlation](#log-correlation). Default `false`. |
 | `logHook`               | `LogHookFunction` | An option hook to inject additional context to a log record after trace-context has been added. This requires `disableLogCorrelation` to be false. |
 

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

@@ -25,6 +25,7 @@ import { BunyanInstrumentationConfig } from './types';
 import { VERSION } from './version';
 import { OpenTelemetryBunyanStream } from './OpenTelemetryBunyanStream';
 import type * as BunyanLogger from 'bunyan';
+import { SeverityNumber } from '@opentelemetry/api-logs';
 
 const DEFAULT_CONFIG: BunyanInstrumentationConfig = {
   disableLogSending: false,
@@ -157,10 +158,15 @@ export class BunyanInstrumentation extends InstrumentationBase<
       return;
     }
     this._diag.debug('Adding OpenTelemetryBunyanStream to logger');
+    let streamLevel = logger.level();
+    if (config.logSeverity) {
+      const bunyanLevel = bunyanLevelFromSeverity(config.logSeverity);
+      streamLevel = bunyanLevel || streamLevel;
+    }
     logger.addStream({
       type: 'raw',
       stream: new OpenTelemetryBunyanStream(),
-      level: logger.level(),
+      level: streamLevel,
     });
   }
 
@@ -182,3 +188,20 @@ export class BunyanInstrumentation extends InstrumentationBase<
     );
   }
 }
+
+function bunyanLevelFromSeverity(severity: SeverityNumber): string | undefined {
+  if (severity >= SeverityNumber.FATAL) {
+    return 'fatal';
+  } else if (severity >= SeverityNumber.ERROR) {
+    return 'error';
+  } else if (severity >= SeverityNumber.WARN) {
+    return 'warn';
+  } else if (severity >= SeverityNumber.INFO) {
+    return 'info';
+  } else if (severity >= SeverityNumber.DEBUG) {
+    return 'debug';
+  } else if (severity >= SeverityNumber.TRACE) {
+    return 'trace';
+  }
+  return;
+}

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

@@ -15,6 +15,7 @@
  */
 
 import { Span } from '@opentelemetry/api';
+import { SeverityNumber } from '@opentelemetry/api-logs';
 import { InstrumentationConfig } from '@opentelemetry/instrumentation';
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
@@ -28,6 +29,11 @@ export interface BunyanInstrumentationConfig extends InstrumentationConfig {
    */
   disableLogSending?: boolean;
 
+  /**
+   * Control Log sending severity level, logs will be sent for  specified severity and higher.
+   */
+  logSeverity?: SeverityNumber;
+
   /**
    * Whether to disable the injection trace-context fields, and possibly other
    * fields from `logHook()`, into log records for log correlation.

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

@@ -319,6 +319,37 @@ describe('BunyanInstrumentation', () => {
       assert.strictEqual(rec.body, 'hi');
       assert.strictEqual(rec.attributes.aProperty, 'bar');
     });
+
+    it('log record level configuration (higher than default)', () => {
+      instrumentation.setConfig({ logSeverity: SeverityNumber.WARN });
+
+      // Setting `logSeverity` only has an impact on Loggers created
+      // *after* it is set. So we cannot test with the `log` created in
+      // `beforeEach()` above.
+      log = Logger.createLogger({ name: 'test-logger-name', stream });
+
+      log.info('info log');
+      log.warn('warn log');
+      const logRecords = memExporter.getFinishedLogRecords();
+      // Only one log record match configured severity
+      assert.strictEqual(logRecords.length, 1);
+      assert.strictEqual(logRecords[0].body, 'warn log');
+    });
+
+    it('log record level configuration (lower than default)', () => {
+      instrumentation.setConfig({ logSeverity: SeverityNumber.DEBUG });
+      log = Logger.createLogger({ name: 'test-logger-name', stream });
+      log.info('info log');
+      log.debug('debug log');
+
+      // Just the log.info() writes to `stream`.
+      sinon.assert.calledOnce(writeSpy);
+      // Both log.info() and log.debug() should be written to the OTel Logs SDK.
+      const logRecords = memExporter.getFinishedLogRecords();
+      assert.strictEqual(logRecords.length, 2);
+      assert.strictEqual(logRecords[0].body, 'info log');
+      assert.strictEqual(logRecords[1].body, 'debug log');
+    });
   });
 
   describe('disabled instrumentation', () => {