feat: add global error handler

packages/opentelemetry-api/src/common/Exception.ts

@@ -15,21 +15,21 @@
  */
 
 interface ExceptionWithCode {
-  code: string;
+  code: string | number;
   name?: string;
   message?: string;
   stack?: string;
 }
 
 interface ExceptionWithMessage {
-  code?: string;
+  code?: string | number;
   message: string;
   name?: string;
   stack?: string;
 }
 
 interface ExceptionWithName {
-  code?: string;
+  code?: string | number;
   message?: string;
   name: string;
   stack?: string;

packages/opentelemetry-core/src/common/global-error-handler.ts

@@ -0,0 +1,40 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Exception } from '@opentelemetry/api';
+import { loggingErrorHandler } from './logging-error-handler';
+import { ErrorHandler } from './types';
+
+/** The global error handler delegate */
+let delegateHandler = loggingErrorHandler();
+
+/**
+ * Set the global error handler
+ * @param {ErrorHandler} handler
+ */
+export function setGlobalErrorHandler(handler: ErrorHandler) {
+  delegateHandler = handler;
+}
+
+/**
+ * Return the global error handler
+ * @param {Exception} ex
+ */
+export const globalErrorHandler = (ex: Exception) => {
+  try {
+    delegateHandler(ex);
+  } catch {} // eslint-disable-line no-empty
+};

packages/opentelemetry-core/src/common/logging-error-handler.ts

@@ -0,0 +1,66 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Logger, Exception } from '@opentelemetry/api';
+import { ConsoleLogger } from './ConsoleLogger';
+import { ErrorHandler, LogLevel } from './types';
+
+/**
+ * Returns a function that logs an error using the provided logger, or a
+ * console logger if one was not provided.
+ * @param {Logger} logger
+ */
+export function loggingErrorHandler(logger?: Logger): ErrorHandler {
+  logger = logger ?? new ConsoleLogger(LogLevel.ERROR);
+  return (ex: Exception) => {
+    logger!.error(stringifyException(ex));
+  };
+}
+
+/**
+ * Converts an exception into a string representation
+ * @param {Exception} ex
+ */
+function stringifyException(ex: Exception | string): string {
+  if (typeof ex === 'string') {
+    return ex;
+  } else {
+    return JSON.stringify(flattenException(ex));
+  }
+}
+
+/**
+ * Flattens an exception into key-value pairs by traversing the prototype chain
+ * and coercing values to strings. Duplicate properties will not be overwritten;
+ * the first insert wins.
+ */
+function flattenException(ex: Exception): Record<string, string> {
+  const result = {} as Record<string, string>;
+  let current = ex;
+
+  while (current !== null) {
+    Object.getOwnPropertyNames(current).forEach(propertyName => {
+      if (result[propertyName]) return;
+      const value = current[propertyName as keyof typeof current];
+      if (value) {
+        result[propertyName] = String(value);
+      }
+    });
+    current = Object.getPrototypeOf(current);
+  }
+
+  return result;
+}

packages/opentelemetry-core/src/common/types.ts

@@ -13,6 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+import { Exception } from '@opentelemetry/api';
+
 export enum LogLevel {
   ERROR,
   WARN,
@@ -56,3 +59,6 @@ export interface InstrumentationLibrary {
   readonly name: string;
   readonly version: string;
 }
+
+/** Defines an error handler function */
+export type ErrorHandler = (ex: Exception) => void;

packages/opentelemetry-core/src/index.ts

@@ -16,6 +16,8 @@
 
 export * from './common/attributes';
 export * from './common/ConsoleLogger';
+export * from './common/global-error-handler';
+export * from './common/logging-error-handler';
 export * from './common/NoopLogger';
 export * from './common/time';
 export * from './common/types';

packages/opentelemetry-core/test/common/global-error-handler.test.ts

@@ -0,0 +1,56 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as assert from 'assert';
+import * as sinon from 'sinon';
+import { globalErrorHandler, setGlobalErrorHandler } from '../../src';
+import { Exception } from '@opentelemetry/api';
+
+describe('globalErrorHandler', () => {
+  let defaultHandler: sinon.SinonSpy;
+
+  beforeEach(() => {
+    defaultHandler = sinon.spy();
+    setGlobalErrorHandler(defaultHandler);
+  });
+
+  it('receives errors', () => {
+    const err = new Error('this is bad');
+    globalErrorHandler(err);
+    sinon.assert.calledOnceWithExactly(defaultHandler, err);
+  });
+
+  it('replaces delegate when handler is updated', () => {
+    const err = new Error('this is bad');
+    const newHandler = sinon.spy();
+    setGlobalErrorHandler(newHandler);
+
+    globalErrorHandler(err);
+
+    sinon.assert.calledOnceWithExactly(newHandler, err);
+    sinon.assert.notCalled(defaultHandler);
+  });
+
+  it('catches exceptions thrown in handler', () => {
+    setGlobalErrorHandler((ex: Exception) => {
+      throw new Error('bad things');
+    });
+
+    assert.doesNotThrow(() => {
+      globalErrorHandler('an error');
+    });
+  });
+});

packages/opentelemetry-core/test/common/logging-error-handler.test.ts

@@ -0,0 +1,75 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as assert from 'assert';
+import * as sinon from 'sinon';
+import { ErrorHandler, loggingErrorHandler } from '../../src';
+
+describe('loggingErrorHandler', () => {
+  let handler: ErrorHandler;
+  const errorStub = sinon.fake();
+
+  beforeEach(() => {
+    handler = loggingErrorHandler({
+      debug: sinon.fake(),
+      info: sinon.fake(),
+      warn: sinon.fake(),
+      error: errorStub,
+    });
+  });
+
+  it('logs from string', () => {
+    const err = 'not found';
+    handler(err);
+    assert.ok(errorStub.calledOnceWith(err));
+  });
+
+  it('logs from an object', () => {
+    const err = {
+      name: 'NotFoundError',
+      message: 'not found',
+      randomString: 'random value',
+      randomNumber: 42,
+      randomArray: [1, 2, 3],
+      randomObject: { a: 'a' },
+      stack: 'a stack',
+    };
+
+    handler(err);
+
+    const [result] = errorStub.lastCall.args;
+
+    assert.ok(result.includes(err.name));
+    assert.ok(result.includes(err.message));
+    assert.ok(result.includes(err.randomString));
+    assert.ok(result.includes(err.randomNumber));
+    assert.ok(result.includes(err.randomArray));
+    assert.ok(result.includes(err.randomObject));
+    assert.ok(result.includes(JSON.stringify(err.stack)));
+  });
+
+  it('logs from an error', () => {
+    const err = new Error('this is bad');
+
+    handler(err);
+
+    const [result] = errorStub.lastCall.args;
+
+    assert.ok(result.includes(err.name));
+    assert.ok(result.includes(err.message));
+    assert.ok(result.includes(JSON.stringify(err.stack)));
+  });
+});

packages/opentelemetry-exporter-collector-proto/src/util.ts

@@ -80,8 +80,6 @@ export function send<ExportItem, ServiceRequest>(
       );
     }
   } else {
-    onError({
-      message: 'No proto',
-    });
+    onError(new collectorTypes.CollectorExporterError('No proto'));
   }
 }

packages/opentelemetry-exporter-collector-proto/test/CollectorMetricExporter.test.ts

@@ -177,7 +177,14 @@ describe('CollectorMetricExporter - node with proto over http', () => {
     });
 
     it('should log the error message', done => {
-      const spyLoggerError = sinon.stub(collectorExporter.logger, 'error');
+      const spyLoggerError = sinon.spy();
+      const handler = core.loggingErrorHandler({
+        debug: sinon.fake(),
+        info: sinon.fake(),
+        warn: sinon.fake(),
+        error: spyLoggerError,
+      });
+      core.setGlobalErrorHandler(handler);
 
       const responseSpy = sinon.spy();
       collectorExporter.export(metrics, responseSpy);
@@ -187,9 +194,8 @@ describe('CollectorMetricExporter - node with proto over http', () => {
         const callback = args[1];
         callback(mockResError);
         setTimeout(() => {
-          const response: any = spyLoggerError.args[0][0];
-          assert.strictEqual(response, 'statusCode: 400');
-
+          const response = spyLoggerError.args[0][0] as string;
+          assert.ok(response.includes('"code":"400"'));
           assert.strictEqual(responseSpy.args[0][0], 1);
           done();
         });

packages/opentelemetry-exporter-collector-proto/test/CollectorTraceExporter.test.ts

@@ -144,7 +144,14 @@ describe('CollectorTraceExporter - node with proto over http', () => {
     });
 
     it('should log the error message', done => {
-      const spyLoggerError = sinon.stub(collectorExporter.logger, 'error');
+      const spyLoggerError = sinon.spy();
+      const handler = core.loggingErrorHandler({
+        debug: sinon.fake(),
+        info: sinon.fake(),
+        warn: sinon.fake(),
+        error: spyLoggerError,
+      });
+      core.setGlobalErrorHandler(handler);
 
       const responseSpy = sinon.spy();
       collectorExporter.export(spans, responseSpy);
@@ -154,9 +161,9 @@ describe('CollectorTraceExporter - node with proto over http', () => {
         const callback = args[1];
         callback(mockResError);
         setTimeout(() => {
-          const response: any = spyLoggerError.args[0][0];
-          assert.strictEqual(response, 'statusCode: 400');
+          const response = spyLoggerError.args[0][0] as string;
 
+          assert.ok(response.includes('"code":"400"'));
           assert.strictEqual(responseSpy.args[0][0], 1);
           done();
         });

packages/opentelemetry-exporter-collector/src/CollectorExporterBase.ts

@@ -15,7 +15,11 @@
  */
 
 import { Attributes, Logger } from '@opentelemetry/api';
-import { ExportResult, NoopLogger } from '@opentelemetry/core';
+import {
+  ExportResult,
+  NoopLogger,
+  globalErrorHandler,
+} from '@opentelemetry/core';
 import {
   CollectorExporterError,
   CollectorExporterConfigBase,
@@ -75,9 +79,7 @@ export abstract class CollectorExporterBase<
         resultCallback(ExportResult.SUCCESS);
       })
       .catch((error: ExportServiceError) => {
-        if (error.message) {
-          this.logger.error(error.message);
-        }
+        globalErrorHandler(error);
         if (error.code && error.code < 500) {
           resultCallback(ExportResult.FAILED_NOT_RETRYABLE);
         } else {