diff --git a/layers/tests/e2e/layerPublisher.class.test.functionCode.ts b/layers/tests/e2e/layerPublisher.class.test.functionCode.ts
index a3ce0497dd..440875dfd1 100644
--- a/layers/tests/e2e/layerPublisher.class.test.functionCode.ts
+++ b/layers/tests/e2e/layerPublisher.class.test.functionCode.ts
@@ -17,7 +17,7 @@ import { SSMClient } from '@aws-sdk/client-ssm';
const logger = new Logger({
logLevel: 'DEBUG',
});
-const metrics = new Metrics();
+const metrics = new Metrics({ logger });
const tracer = new Tracer();
// Instantiating these clients and the respective providers/persistence layers
diff --git a/layers/tests/e2e/layerPublisher.test.ts b/layers/tests/e2e/layerPublisher.test.ts
index 3cb7697031..cbffc8abfa 100644
--- a/layers/tests/e2e/layerPublisher.test.ts
+++ b/layers/tests/e2e/layerPublisher.test.ts
@@ -143,15 +143,10 @@ describe('Layers E2E tests', () => {
const logs = invocationLogs.getFunctionLogs('WARN');
expect(logs.length).toBe(1);
- expect(
- invocationLogs.doesAnyFunctionLogsContains(
- /Namespace should be defined, default used/,
- 'WARN'
- )
- ).toBe(true);
- /* expect(logEntry.message).toEqual(
+ const logEntry = TestInvocationLogs.parseFunctionLog(logs[0]);
+ expect(logEntry.message).toEqual(
'Namespace should be defined, default used'
- ); */
+ );
}
);
diff --git a/packages/commons/src/types/GenericLogger.ts b/packages/commons/src/types/GenericLogger.ts
new file mode 100644
index 0000000000..0e5da7a716
--- /dev/null
+++ b/packages/commons/src/types/GenericLogger.ts
@@ -0,0 +1,17 @@
+// biome-ignore lint/suspicious/noExplicitAny: We intentionally use `any` here to represent any type of data and keep the logger is as flexible as possible.
+type Anything = any[];
+
+/**
+ * Interface for a generic logger object.
+ *
+ * This interface is used to define the shape of a logger object that can be passed to a Powertools for AWS utility.
+ *
+ * It can be an instance of Logger from Powertools for AWS, or any other logger that implements the same methods.
+ */
+export interface GenericLogger {
+ trace?: (...content: Anything) => void;
+ debug: (...content: Anything) => void;
+ info: (...content: Anything) => void;
+ warn: (...content: Anything) => void;
+ error: (...content: Anything) => void;
+}
diff --git a/packages/commons/src/types/index.ts b/packages/commons/src/types/index.ts
index 24fb3b8032..080d13ed12 100644
--- a/packages/commons/src/types/index.ts
+++ b/packages/commons/src/types/index.ts
@@ -5,6 +5,7 @@ export type {
MiddlewareFn,
CleanupFunction,
} from './middy.js';
+export type { GenericLogger } from './GenericLogger.js';
export type { SdkClient, MiddlewareArgsLike } from './awsSdk.js';
export type {
JSONPrimitive,
diff --git a/packages/metrics/src/Metrics.ts b/packages/metrics/src/Metrics.ts
index 559ff71b91..abe8fac81b 100644
--- a/packages/metrics/src/Metrics.ts
+++ b/packages/metrics/src/Metrics.ts
@@ -1,6 +1,9 @@
import { Console } from 'node:console';
import { Utility } from '@aws-lambda-powertools/commons';
-import type { HandlerMethodDecorator } from '@aws-lambda-powertools/commons/types';
+import type {
+ GenericLogger,
+ HandlerMethodDecorator,
+} from '@aws-lambda-powertools/commons/types';
import type { Callback, Context, Handler } from 'aws-lambda';
import { EnvironmentVariablesService } from './config/EnvironmentVariablesService.js';
import {
@@ -159,6 +162,13 @@ class Metrics extends Utility implements MetricsInterface {
*/
private functionName?: string;
+ /**
+ * Custom logger object used for emitting debug, warning, and error messages.
+ *
+ * Note that this logger is not used for emitting metrics which are emitted to standard output using the `Console` object.
+ */
+ readonly #logger: GenericLogger;
+
/**
* Flag indicating if this is a single metric instance
* @default false
@@ -193,6 +203,7 @@ class Metrics extends Utility implements MetricsInterface {
this.dimensions = {};
this.setOptions(options);
+ this.#logger = options.logger || this.console;
}
/**
@@ -439,6 +450,13 @@ class Metrics extends Utility implements MetricsInterface {
this.storedMetrics = {};
}
+ /**
+ * Check if there are stored metrics in the buffer.
+ */
+ public hasStoredMetrics(): boolean {
+ return Object.keys(this.storedMetrics).length > 0;
+ }
+
/**
* A class method decorator to automatically log metrics after the method returns or throws an error.
*
@@ -539,9 +557,9 @@ class Metrics extends Utility implements MetricsInterface {
* ```
*/
public publishStoredMetrics(): void {
- const hasMetrics = Object.keys(this.storedMetrics).length > 0;
+ const hasMetrics = this.hasStoredMetrics();
if (!this.shouldThrowOnEmptyMetrics && !hasMetrics) {
- console.warn(
+ this.#logger.warn(
'No application metrics to publish. The cold-start metric may be published if enabled. ' +
'If application metrics should never be empty, consider using `throwOnEmptyMetrics`'
);
@@ -584,7 +602,7 @@ class Metrics extends Utility implements MetricsInterface {
}
if (!this.namespace)
- console.warn('Namespace should be defined, default used');
+ this.#logger.warn('Namespace should be defined, default used');
// We reduce the stored metrics to a single object with the metric
// name as the key and the value as the value.
@@ -731,6 +749,7 @@ class Metrics extends Utility implements MetricsInterface {
serviceName: this.dimensions.service,
defaultDimensions: this.defaultDimensions,
singleMetric: true,
+ logger: this.#logger,
});
}
diff --git a/packages/metrics/src/types/Metrics.ts b/packages/metrics/src/types/Metrics.ts
index 1c65dc5212..f02f9b183a 100644
--- a/packages/metrics/src/types/Metrics.ts
+++ b/packages/metrics/src/types/Metrics.ts
@@ -1,4 +1,7 @@
-import type { HandlerMethodDecorator } from '@aws-lambda-powertools/commons/types';
+import type {
+ GenericLogger,
+ HandlerMethodDecorator,
+} from '@aws-lambda-powertools/commons/types';
import type {
MetricResolution as MetricResolutions,
MetricUnit as MetricUnits,
@@ -57,6 +60,15 @@ type MetricsOptions = {
* @see {@link MetricsInterface.setDefaultDimensions | `setDefaultDimensions()`}
*/
defaultDimensions?: Dimensions;
+ /**
+ * Logger object to be used for emitting debug, warning, and error messages.
+ *
+ * If not provided, debug messages will be suppressed, and warning and error messages will be sent to stdout.
+ *
+ * Note that EMF metrics are always sent directly to stdout, regardless of the logger
+ * to avoid compatibility issues with custom loggers.
+ */
+ logger?: GenericLogger;
};
/**
diff --git a/packages/metrics/tests/unit/Metrics.test.ts b/packages/metrics/tests/unit/Metrics.test.ts
index b68d2b7e38..8b75a21faf 100644
--- a/packages/metrics/tests/unit/Metrics.test.ts
+++ b/packages/metrics/tests/unit/Metrics.test.ts
@@ -27,6 +27,8 @@ jest.mock('node:console', () => ({
...jest.requireActual('node:console'),
Console: jest.fn().mockImplementation(() => ({
log: jest.fn(),
+ warn: jest.fn(),
+ debug: jest.fn(),
})),
}));
jest.spyOn(console, 'warn').mockImplementation(() => ({}));
@@ -1254,9 +1256,17 @@ describe('Class: Metrics', () => {
describe('Methods: publishStoredMetrics', () => {
test('it should log warning if no metrics are added & throwOnEmptyMetrics is false', () => {
// Prepare
- const metrics: Metrics = new Metrics({ namespace: TEST_NAMESPACE });
- const consoleWarnSpy = jest.spyOn(console, 'warn').mockImplementation();
- const consoleLogSpy = jest.spyOn(console, 'log').mockImplementation();
+ const customLogger = {
+ warn: jest.fn(),
+ debug: jest.fn(),
+ error: jest.fn(),
+ info: jest.fn(),
+ };
+ const metrics: Metrics = new Metrics({
+ namespace: TEST_NAMESPACE,
+ logger: customLogger,
+ });
+ const consoleWarnSpy = jest.spyOn(customLogger, 'warn');
// Act
metrics.publishStoredMetrics();
@@ -1266,7 +1276,6 @@ describe('Class: Metrics', () => {
expect(consoleWarnSpy).toHaveBeenCalledWith(
'No application metrics to publish. The cold-start metric may be published if enabled. If application metrics should never be empty, consider using `throwOnEmptyMetrics`'
);
- expect(consoleLogSpy).not.toHaveBeenCalled();
});
test('it should call serializeMetrics && log the stringified return value of serializeMetrics', () => {
@@ -1355,8 +1364,14 @@ describe('Class: Metrics', () => {
test('it should print warning, if no namespace provided in constructor or environment variable', () => {
// Prepare
process.env.POWERTOOLS_METRICS_NAMESPACE = '';
- const metrics: Metrics = new Metrics();
- const consoleWarnSpy = jest.spyOn(console, 'warn').mockImplementation();
+ const customLogger = {
+ warn: jest.fn(),
+ debug: jest.fn(),
+ error: jest.fn(),
+ info: jest.fn(),
+ };
+ const metrics: Metrics = new Metrics({ logger: customLogger });
+ const consoleWarnSpy = jest.spyOn(customLogger, 'warn');
// Act
metrics.serializeMetrics();
diff --git a/packages/metrics/tests/unit/middleware/middy.test.ts b/packages/metrics/tests/unit/middleware/middy.test.ts
index fc9ddec7e8..8d2a17ec51 100644
--- a/packages/metrics/tests/unit/middleware/middy.test.ts
+++ b/packages/metrics/tests/unit/middleware/middy.test.ts
@@ -14,6 +14,8 @@ jest.mock('node:console', () => ({
...jest.requireActual('node:console'),
Console: jest.fn().mockImplementation(() => ({
log: jest.fn(),
+ warn: jest.fn(),
+ debug: jest.fn(),
})),
}));
jest.spyOn(console, 'warn').mockImplementation(() => ({}));
@@ -68,6 +70,7 @@ describe('Middy middleware', () => {
const metrics = new Metrics({
namespace: 'serverlessAirline',
serviceName: 'orders',
+ logger: console,
});
const consoleWarnSpy = jest.spyOn(console, 'warn').mockImplementation();
const handler = middy(async (): Promise<void> => undefined).use(
diff --git a/packages/metrics/tests/unit/repro.test.ts b/packages/metrics/tests/unit/repro.test.ts
deleted file mode 100644
index c1ac3dafed..0000000000
--- a/packages/metrics/tests/unit/repro.test.ts
+++ /dev/null
@@ -1,71 +0,0 @@
-import middy from '@middy/core';
-import type { Context } from 'aws-lambda';
-import { Metrics } from '../../src/Metrics.js';
-import { logMetrics } from '../../src/middleware/middy.js';
-
-describe('Metrics', () => {
- beforeAll(() => {
- jest.spyOn(console, 'warn').mockImplementation();
- });
-
- afterEach(() => {
- jest.resetAllMocks();
- });
-
- it('does not log', () => {
- process.env.POWERTOOLS_DEV = 'true';
- const metrics = new Metrics({
- serviceName: 'foo',
- namespace: 'bar',
- defaultDimensions: {
- aws_account_id: '123456789012',
- aws_region: 'us-west-2',
- },
- });
- const logSpy = jest.spyOn(console, 'log').mockImplementation();
-
- metrics.publishStoredMetrics();
-
- expect(logSpy).toHaveBeenCalledTimes(0);
- });
-
- it('does log because of captureColdStartMetric enabled', () => {
- process.env.POWERTOOLS_DEV = 'true';
- const metrics = new Metrics({
- serviceName: 'foo',
- namespace: 'bar',
- defaultDimensions: {
- aws_account_id: '123456789012',
- aws_region: 'us-west-2',
- },
- });
- const logSpy = jest.spyOn(console, 'log').mockImplementation();
- const handler = middy(() => {}).use(
- logMetrics(metrics, { captureColdStartMetric: true })
- );
-
- handler({}, {} as Context);
-
- expect(logSpy).toHaveBeenCalledTimes(1);
- });
-
- it('does not log because of captureColdStartMetric disabled', () => {
- process.env.POWERTOOLS_DEV = 'true';
- const metrics = new Metrics({
- serviceName: 'foo',
- namespace: 'bar',
- defaultDimensions: {
- aws_account_id: '123456789012',
- aws_region: 'us-west-2',
- },
- });
- const logSpy = jest.spyOn(console, 'log').mockImplementation();
- const handler = middy(() => {}).use(
- logMetrics(metrics, { captureColdStartMetric: false })
- );
-
- handler({}, {} as Context);
-
- expect(logSpy).toHaveBeenCalledTimes(0);
- });
-});