feat(core): Add support for beforeSendLog

packages/core/src/client.ts

@@ -623,12 +623,19 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public on(hook: 'close', callback: () => void): () => void;
 
  /**
- * A hook that is called before a log is captured
+ * A hook that is called before a log is captured. This hooks runs before `beforeSendLog` is fired.
  *
  * @returns {() => void} A function that, when executed, removes the registered callback.
  */
  public on(hook: 'beforeCaptureLog', callback: (log: Log) => void): () => void;
 
+ /**
+ * A hook that is called after a log is captured
+ *
+ * @returns {() => void} A function that, when executed, removes the registered callback.
+ */
+ public on(hook: 'afterCaptureLog', callback: (log: Log) => void): () => void;
+
  /**
  * Register a hook on this client.
  */
@@ -777,10 +784,15 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public emit(hook: 'close'): void;
 
  /**
- * Emit a hook event for client before capturing a log
+ * Emit a hook event for client before capturing a log. This hooks runs before `beforeSendLog` is fired.
  */
  public emit(hook: 'beforeCaptureLog', log: Log): void;
 
+ /**
+ * Emit a hook event for client after capturing a log.
+ */
+ public emit(hook: 'afterCaptureLog', log: Log): void;
+
  /**
  * Emit a hook that was previously registered via `on()`.
  */

packages/core/src/logs/index.ts

@@ -62,18 +62,28 @@ export function logAttributeToSerializedLogAttribute(key: string, value: unknown
  * @experimental This method will experience breaking changes. This is not yet part of
  * the stable Sentry SDK API and can be changed or removed without warning.
  */
-export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = getCurrentScope()): void {
+export function _INTERNAL_captureLog(beforeLog: Log, client = getClient(), scope = getCurrentScope()): void {
  if (!client) {
  DEBUG_BUILD && logger.warn('No client available to capture log.');
  return;
  }
 
  const { _experiments, release, environment } = client.getOptions();
- if (!_experiments?.enableLogs) {
+ const { enableLogs = false, beforeSendLog } = _experiments ?? {};
+ if (!enableLogs) {
  DEBUG_BUILD && logger.warn('logging option not enabled, log will not be captured.');
  return;
  }
 
+ client.emit('beforeCaptureLog', beforeLog);
+
+ const log = beforeSendLog ? beforeSendLog(beforeLog) : beforeLog;
+ if (!log) {
+ client.recordDroppedEvent('before_send', 'log_item', 1);
+ DEBUG_BUILD && logger.warn('beforeSendLog returned null, log will not be captured.');
+ return;
+ }
+
  const [, traceContext] = _getTraceInfoFromScope(client, scope);
 
  const { level, message, attributes, severityNumber } = log;
@@ -117,7 +127,7 @@ export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = get
  }
  }
 
- client.emit('beforeCaptureLog', log);
+ client.emit('afterCaptureLog', log);
 }
 
 /**

packages/core/src/server-runtime-client.ts

@@ -57,7 +57,7 @@ export class ServerRuntimeClient<
  _INTERNAL_flushLogsBuffer(client);
  });
 
- this.on('beforeCaptureLog', log => {
+ this.on('afterCaptureLog', log => {
  client._logWeight += estimateLogSizeInBytes(log);
 
  // We flush the logs buffer if it exceeds 0.8 MB

packages/core/src/types-hoist/options.ts

@@ -2,6 +2,7 @@ import type { CaptureContext } from '../scope';
 import type { Breadcrumb, BreadcrumbHint } from './breadcrumb';
 import type { ErrorEvent, EventHint, TransactionEvent } from './event';
 import type { Integration } from './integration';
+import type { Log } from './log';
 import type { TracesSamplerSamplingContext } from './samplingcontext';
 import type { SdkMetadata } from './sdkmetadata';
 import type { SpanJSON } from './span';
@@ -188,6 +189,17 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
  * If logs support should be enabled. Defaults to false.
  */
  enableLogs?: boolean;
+ /**
+ * An event-processing callback for logs, guaranteed to be invoked after all other log
+ * processors. This allows a log to be modified or dropped before it's sent.
+ *
+ * Note that you must return a valid log from this callback. If you do not wish to modify the log, simply return
+ * it at the end. Returning `null` will cause the log to be dropped.
+ *
+ * @param log The log generated by the SDK.
+ * @returns A new log that will be sent | null.
+ */
+ beforeSendLog?: (log: Log) => Log | null;
  };
 
  /**

packages/core/test/lib/log/index.test.ts

@@ -8,6 +8,7 @@ import {
 import { TestClient, getDefaultTestClientOptions } from '../../mocks/client';
 import * as loggerModule from '../../../src/utils-hoist/logger';
 import { Scope } from '../../../src';
+import type { Log } from '../../../src/types-hoist/log';
 
 const PUBLIC_DSN = 'https://username@domain/123';
 
@@ -187,4 +188,94 @@ describe('_INTERNAL_captureLog', () => {
  _INTERNAL_flushLogsBuffer(client);
  expect(mockSendEnvelope).not.toHaveBeenCalled();
  });
+
+ it('processes logs through beforeSendLog when provided', () => {
+ const beforeSendLog = vi.fn().mockImplementation(log => ({
+ ...log,
+ message: `Modified: ${log.message}`,
+ attributes: { ...log.attributes, processed: true },
+ }));
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalledWith({
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ });
+
+ const logBuffer = _INTERNAL_getLogBuffer(client);
+ expect(logBuffer).toBeDefined();
+ expect(logBuffer?.[0]).toEqual(
+ expect.objectContaining({
+ body: {
+ stringValue: 'Modified: original message',
+ },
+ attributes: expect.arrayContaining([
+ expect.objectContaining({ key: 'processed', value: { boolValue: true } }),
+ expect.objectContaining({ key: 'original', value: { boolValue: true } }),
+ ]),
+ }),
+ );
+ });
+
+ it('drops logs when beforeSendLog returns null', () => {
+ const beforeSendLog = vi.fn().mockReturnValue(null);
+ const recordDroppedEventSpy = vi.spyOn(TestClient.prototype, 'recordDroppedEvent');
+ const loggerWarnSpy = vi.spyOn(loggerModule.logger, 'warn').mockImplementation(() => undefined);
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'test message',
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalled();
+ expect(recordDroppedEventSpy).toHaveBeenCalledWith('before_send', 'log_item', 1);
+ expect(loggerWarnSpy).toHaveBeenCalledWith('beforeSendLog returned null, log will not be captured.');
+ expect(_INTERNAL_getLogBuffer(client)).toBeUndefined();
+
+ recordDroppedEventSpy.mockRestore();
+ loggerWarnSpy.mockRestore();
+ });
+
+ it('emits beforeCaptureLog and afterCaptureLog events', () => {
+ const beforeCaptureLogSpy = vi.spyOn(TestClient.prototype, 'emit');
+ const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, _experiments: { enableLogs: true } });
+ const client = new TestClient(options);
+
+ const log: Log = {
+ level: 'info',
+ message: 'test message',
+ };
+
+ _INTERNAL_captureLog(log, client, undefined);
+
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('beforeCaptureLog', log);
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('afterCaptureLog', log);
+ beforeCaptureLogSpy.mockRestore();
+ });
 });

packages/core/src/client.ts

@@ -623,12 +623,19 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public on(hook: 'close', callback: () => void): () => void;
 
  /**
- * A hook that is called before a log is captured
+ * A hook that is called before a log is captured. This hooks runs before `beforeSendLog` is fired.
  *
  * @returns {() => void} A function that, when executed, removes the registered callback.
  */
  public on(hook: 'beforeCaptureLog', callback: (log: Log) => void): () => void;
 
+ /**
+ * A hook that is called after a log is captured
+ *
+ * @returns {() => void} A function that, when executed, removes the registered callback.
+ */
+ public on(hook: 'afterCaptureLog', callback: (log: Log) => void): () => void;
+
  /**
  * Register a hook on this client.
  */
@@ -777,10 +784,15 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public emit(hook: 'close'): void;
 
  /**
- * Emit a hook event for client before capturing a log
+ * Emit a hook event for client before capturing a log. This hooks runs before `beforeSendLog` is fired.
  */
  public emit(hook: 'beforeCaptureLog', log: Log): void;
 
+ /**
+ * Emit a hook event for client after capturing a log.
+ */
+ public emit(hook: 'afterCaptureLog', log: Log): void;
+
  /**
  * Emit a hook that was previously registered via `on()`.
  */

packages/core/src/logs/index.ts

@@ -62,18 +62,28 @@ export function logAttributeToSerializedLogAttribute(key: string, value: unknown
  * @experimental This method will experience breaking changes. This is not yet part of
  * the stable Sentry SDK API and can be changed or removed without warning.
  */
-export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = getCurrentScope()): void {
+export function _INTERNAL_captureLog(beforeLog: Log, client = getClient(), scope = getCurrentScope()): void {
  if (!client) {
  DEBUG_BUILD && logger.warn('No client available to capture log.');
  return;
  }
 
  const { _experiments, release, environment } = client.getOptions();
- if (!_experiments?.enableLogs) {
+ const { enableLogs = false, beforeSendLog } = _experiments ?? {};
+ if (!enableLogs) {
  DEBUG_BUILD && logger.warn('logging option not enabled, log will not be captured.');
  return;
  }
 
+ client.emit('beforeCaptureLog', beforeLog);
+
+ const log = beforeSendLog ? beforeSendLog(beforeLog) : beforeLog;
+ if (!log) {
+ client.recordDroppedEvent('before_send', 'log_item', 1);
+ DEBUG_BUILD && logger.warn('beforeSendLog returned null, log will not be captured.');
+ return;
+ }
+
  const [, traceContext] = _getTraceInfoFromScope(client, scope);
 
  const { level, message, attributes, severityNumber } = log;
@@ -117,7 +127,7 @@ export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = get
  }
  }
 
- client.emit('beforeCaptureLog', log);
+ client.emit('afterCaptureLog', log);
 }
 
 /**

packages/core/src/server-runtime-client.ts

@@ -57,7 +57,7 @@ export class ServerRuntimeClient<
  _INTERNAL_flushLogsBuffer(client);
  });
 
- this.on('beforeCaptureLog', log => {
+ this.on('afterCaptureLog', log => {
  client._logWeight += estimateLogSizeInBytes(log);
 
  // We flush the logs buffer if it exceeds 0.8 MB

packages/core/src/types-hoist/options.ts

@@ -2,6 +2,7 @@ import type { CaptureContext } from '../scope';
 import type { Breadcrumb, BreadcrumbHint } from './breadcrumb';
 import type { ErrorEvent, EventHint, TransactionEvent } from './event';
 import type { Integration } from './integration';
+import type { Log } from './log';
 import type { TracesSamplerSamplingContext } from './samplingcontext';
 import type { SdkMetadata } from './sdkmetadata';
 import type { SpanJSON } from './span';
@@ -188,6 +189,17 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
  * If logs support should be enabled. Defaults to false.
  */
  enableLogs?: boolean;
+ /**
+ * An event-processing callback for logs, guaranteed to be invoked after all other log
+ * processors. This allows a log to be modified or dropped before it's sent.
+ *
+ * Note that you must return a valid log from this callback. If you do not wish to modify the log, simply return
+ * it at the end. Returning `null` will cause the log to be dropped.
+ *
+ * @param log The log generated by the SDK.
+ * @returns A new log that will be sent | null.
+ */
+ beforeSendLog?: (log: Log) => Log | null;
  };
 
  /**

packages/core/test/lib/log/index.test.ts

@@ -8,6 +8,7 @@ import {
 import { TestClient, getDefaultTestClientOptions } from '../../mocks/client';
 import * as loggerModule from '../../../src/utils-hoist/logger';
 import { Scope } from '../../../src';
+import type { Log } from '../../../src/types-hoist/log';
 
 const PUBLIC_DSN = 'https://username@domain/123';
 
@@ -187,4 +188,94 @@ describe('_INTERNAL_captureLog', () => {
  _INTERNAL_flushLogsBuffer(client);
  expect(mockSendEnvelope).not.toHaveBeenCalled();
  });
+
+ it('processes logs through beforeSendLog when provided', () => {
+ const beforeSendLog = vi.fn().mockImplementation(log => ({
+ ...log,
+ message: `Modified: ${log.message}`,
+ attributes: { ...log.attributes, processed: true },
+ }));
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalledWith({
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ });
+
+ const logBuffer = _INTERNAL_getLogBuffer(client);
+ expect(logBuffer).toBeDefined();
+ expect(logBuffer?.[0]).toEqual(
+ expect.objectContaining({
+ body: {
+ stringValue: 'Modified: original message',
+ },
+ attributes: expect.arrayContaining([
+ expect.objectContaining({ key: 'processed', value: { boolValue: true } }),
+ expect.objectContaining({ key: 'original', value: { boolValue: true } }),
+ ]),
+ }),
+ );
+ });
+
+ it('drops logs when beforeSendLog returns null', () => {
+ const beforeSendLog = vi.fn().mockReturnValue(null);
+ const recordDroppedEventSpy = vi.spyOn(TestClient.prototype, 'recordDroppedEvent');
+ const loggerWarnSpy = vi.spyOn(loggerModule.logger, 'warn').mockImplementation(() => undefined);
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'test message',
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalled();
+ expect(recordDroppedEventSpy).toHaveBeenCalledWith('before_send', 'log_item', 1);
+ expect(loggerWarnSpy).toHaveBeenCalledWith('beforeSendLog returned null, log will not be captured.');
+ expect(_INTERNAL_getLogBuffer(client)).toBeUndefined();
+
+ recordDroppedEventSpy.mockRestore();
+ loggerWarnSpy.mockRestore();
+ });
+
+ it('emits beforeCaptureLog and afterCaptureLog events', () => {
+ const beforeCaptureLogSpy = vi.spyOn(TestClient.prototype, 'emit');
+ const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, _experiments: { enableLogs: true } });
+ const client = new TestClient(options);
+
+ const log: Log = {
+ level: 'info',
+ message: 'test message',
+ };
+
+ _INTERNAL_captureLog(log, client, undefined);
+
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('beforeCaptureLog', log);
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('afterCaptureLog', log);
+ beforeCaptureLogSpy.mockRestore();
+ });
 });

packages/core/src/client.ts

@@ -623,12 +623,19 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public on(hook: 'close', callback: () => void): () => void;
 
  /**
- * A hook that is called before a log is captured
+ * A hook that is called before a log is captured. This hooks runs before `beforeSendLog` is fired.
  *
  * @returns {() => void} A function that, when executed, removes the registered callback.
  */
  public on(hook: 'beforeCaptureLog', callback: (log: Log) => void): () => void;
 
+ /**
+ * A hook that is called after a log is captured
+ *
+ * @returns {() => void} A function that, when executed, removes the registered callback.
+ */
+ public on(hook: 'afterCaptureLog', callback: (log: Log) => void): () => void;
+
  /**
  * Register a hook on this client.
  */
@@ -777,10 +784,15 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public emit(hook: 'close'): void;
 
  /**
- * Emit a hook event for client before capturing a log
+ * Emit a hook event for client before capturing a log. This hooks runs before `beforeSendLog` is fired.
  */
  public emit(hook: 'beforeCaptureLog', log: Log): void;
 
+ /**
+ * Emit a hook event for client after capturing a log.
+ */
+ public emit(hook: 'afterCaptureLog', log: Log): void;
+
  /**
  * Emit a hook that was previously registered via `on()`.
  */

packages/core/src/logs/index.ts

@@ -62,18 +62,28 @@ export function logAttributeToSerializedLogAttribute(key: string, value: unknown
  * @experimental This method will experience breaking changes. This is not yet part of
  * the stable Sentry SDK API and can be changed or removed without warning.
  */
-export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = getCurrentScope()): void {
+export function _INTERNAL_captureLog(beforeLog: Log, client = getClient(), scope = getCurrentScope()): void {
  if (!client) {
  DEBUG_BUILD && logger.warn('No client available to capture log.');
  return;
  }
 
  const { _experiments, release, environment } = client.getOptions();
- if (!_experiments?.enableLogs) {
+ const { enableLogs = false, beforeSendLog } = _experiments ?? {};
+ if (!enableLogs) {
  DEBUG_BUILD && logger.warn('logging option not enabled, log will not be captured.');
  return;
  }
 
+ client.emit('beforeCaptureLog', beforeLog);
+
+ const log = beforeSendLog ? beforeSendLog(beforeLog) : beforeLog;
+ if (!log) {
+ client.recordDroppedEvent('before_send', 'log_item', 1);
+ DEBUG_BUILD && logger.warn('beforeSendLog returned null, log will not be captured.');
+ return;
+ }
+
  const [, traceContext] = _getTraceInfoFromScope(client, scope);
 
  const { level, message, attributes, severityNumber } = log;
@@ -117,7 +127,7 @@ export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = get
  }
  }
 
- client.emit('beforeCaptureLog', log);
+ client.emit('afterCaptureLog', log);
 }
 
 /**

packages/core/src/server-runtime-client.ts

@@ -57,7 +57,7 @@ export class ServerRuntimeClient<
  _INTERNAL_flushLogsBuffer(client);
  });
 
- this.on('beforeCaptureLog', log => {
+ this.on('afterCaptureLog', log => {
  client._logWeight += estimateLogSizeInBytes(log);
 
  // We flush the logs buffer if it exceeds 0.8 MB

packages/core/src/types-hoist/options.ts

@@ -2,6 +2,7 @@ import type { CaptureContext } from '../scope';
 import type { Breadcrumb, BreadcrumbHint } from './breadcrumb';
 import type { ErrorEvent, EventHint, TransactionEvent } from './event';
 import type { Integration } from './integration';
+import type { Log } from './log';
 import type { TracesSamplerSamplingContext } from './samplingcontext';
 import type { SdkMetadata } from './sdkmetadata';
 import type { SpanJSON } from './span';
@@ -188,6 +189,17 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
  * If logs support should be enabled. Defaults to false.
  */
  enableLogs?: boolean;
+ /**
+ * An event-processing callback for logs, guaranteed to be invoked after all other log
+ * processors. This allows a log to be modified or dropped before it's sent.
+ *
+ * Note that you must return a valid log from this callback. If you do not wish to modify the log, simply return
+ * it at the end. Returning `null` will cause the log to be dropped.
+ *
+ * @param log The log generated by the SDK.
+ * @returns A new log that will be sent | null.
+ */
+ beforeSendLog?: (log: Log) => Log | null;
  };
 
  /**

packages/core/test/lib/log/index.test.ts

@@ -8,6 +8,7 @@ import {
 import { TestClient, getDefaultTestClientOptions } from '../../mocks/client';
 import * as loggerModule from '../../../src/utils-hoist/logger';
 import { Scope } from '../../../src';
+import type { Log } from '../../../src/types-hoist/log';
 
 const PUBLIC_DSN = 'https://username@domain/123';
 
@@ -187,4 +188,94 @@ describe('_INTERNAL_captureLog', () => {
  _INTERNAL_flushLogsBuffer(client);
  expect(mockSendEnvelope).not.toHaveBeenCalled();
  });
+
+ it('processes logs through beforeSendLog when provided', () => {
+ const beforeSendLog = vi.fn().mockImplementation(log => ({
+ ...log,
+ message: `Modified: ${log.message}`,
+ attributes: { ...log.attributes, processed: true },
+ }));
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalledWith({
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ });
+
+ const logBuffer = _INTERNAL_getLogBuffer(client);
+ expect(logBuffer).toBeDefined();
+ expect(logBuffer?.[0]).toEqual(
+ expect.objectContaining({
+ body: {
+ stringValue: 'Modified: original message',
+ },
+ attributes: expect.arrayContaining([
+ expect.objectContaining({ key: 'processed', value: { boolValue: true } }),
+ expect.objectContaining({ key: 'original', value: { boolValue: true } }),
+ ]),
+ }),
+ );
+ });
+
+ it('drops logs when beforeSendLog returns null', () => {
+ const beforeSendLog = vi.fn().mockReturnValue(null);
+ const recordDroppedEventSpy = vi.spyOn(TestClient.prototype, 'recordDroppedEvent');
+ const loggerWarnSpy = vi.spyOn(loggerModule.logger, 'warn').mockImplementation(() => undefined);
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'test message',
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalled();
+ expect(recordDroppedEventSpy).toHaveBeenCalledWith('before_send', 'log_item', 1);
+ expect(loggerWarnSpy).toHaveBeenCalledWith('beforeSendLog returned null, log will not be captured.');
+ expect(_INTERNAL_getLogBuffer(client)).toBeUndefined();
+
+ recordDroppedEventSpy.mockRestore();
+ loggerWarnSpy.mockRestore();
+ });
+
+ it('emits beforeCaptureLog and afterCaptureLog events', () => {
+ const beforeCaptureLogSpy = vi.spyOn(TestClient.prototype, 'emit');
+ const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, _experiments: { enableLogs: true } });
+ const client = new TestClient(options);
+
+ const log: Log = {
+ level: 'info',
+ message: 'test message',
+ };
+
+ _INTERNAL_captureLog(log, client, undefined);
+
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('beforeCaptureLog', log);
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('afterCaptureLog', log);
+ beforeCaptureLogSpy.mockRestore();
+ });
 });

packages/core/src/client.ts

@@ -623,12 +623,19 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public on(hook: 'close', callback: () => void): () => void;
 
  /**
- * A hook that is called before a log is captured
+ * A hook that is called before a log is captured. This hooks runs before `beforeSendLog` is fired.
  *
  * @returns {() => void} A function that, when executed, removes the registered callback.
  */
  public on(hook: 'beforeCaptureLog', callback: (log: Log) => void): () => void;
 
+ /**
+ * A hook that is called after a log is captured
+ *
+ * @returns {() => void} A function that, when executed, removes the registered callback.
+ */
+ public on(hook: 'afterCaptureLog', callback: (log: Log) => void): () => void;
+
  /**
  * Register a hook on this client.
  */
@@ -777,10 +784,15 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public emit(hook: 'close'): void;
 
  /**
- * Emit a hook event for client before capturing a log
+ * Emit a hook event for client before capturing a log. This hooks runs before `beforeSendLog` is fired.
  */
  public emit(hook: 'beforeCaptureLog', log: Log): void;
 
+ /**
+ * Emit a hook event for client after capturing a log.
+ */
+ public emit(hook: 'afterCaptureLog', log: Log): void;
+
  /**
  * Emit a hook that was previously registered via `on()`.
  */

packages/core/src/logs/index.ts

@@ -62,18 +62,28 @@ export function logAttributeToSerializedLogAttribute(key: string, value: unknown
  * @experimental This method will experience breaking changes. This is not yet part of
  * the stable Sentry SDK API and can be changed or removed without warning.
  */
-export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = getCurrentScope()): void {
+export function _INTERNAL_captureLog(beforeLog: Log, client = getClient(), scope = getCurrentScope()): void {
  if (!client) {
  DEBUG_BUILD && logger.warn('No client available to capture log.');
  return;
  }
 
  const { _experiments, release, environment } = client.getOptions();
- if (!_experiments?.enableLogs) {
+ const { enableLogs = false, beforeSendLog } = _experiments ?? {};
+ if (!enableLogs) {
  DEBUG_BUILD && logger.warn('logging option not enabled, log will not be captured.');
  return;
  }
 
+ client.emit('beforeCaptureLog', beforeLog);
+
+ const log = beforeSendLog ? beforeSendLog(beforeLog) : beforeLog;
+ if (!log) {
+ client.recordDroppedEvent('before_send', 'log_item', 1);
+ DEBUG_BUILD && logger.warn('beforeSendLog returned null, log will not be captured.');
+ return;
+ }
+
  const [, traceContext] = _getTraceInfoFromScope(client, scope);
 
  const { level, message, attributes, severityNumber } = log;
@@ -117,7 +127,7 @@ export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = get
  }
  }
 
- client.emit('beforeCaptureLog', log);
+ client.emit('afterCaptureLog', log);
 }
 
 /**

packages/core/src/server-runtime-client.ts

@@ -57,7 +57,7 @@ export class ServerRuntimeClient<
  _INTERNAL_flushLogsBuffer(client);
  });
 
- this.on('beforeCaptureLog', log => {
+ this.on('afterCaptureLog', log => {
  client._logWeight += estimateLogSizeInBytes(log);
 
  // We flush the logs buffer if it exceeds 0.8 MB

packages/core/src/types-hoist/options.ts

@@ -2,6 +2,7 @@ import type { CaptureContext } from '../scope';
 import type { Breadcrumb, BreadcrumbHint } from './breadcrumb';
 import type { ErrorEvent, EventHint, TransactionEvent } from './event';
 import type { Integration } from './integration';
+import type { Log } from './log';
 import type { TracesSamplerSamplingContext } from './samplingcontext';
 import type { SdkMetadata } from './sdkmetadata';
 import type { SpanJSON } from './span';
@@ -188,6 +189,17 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
  * If logs support should be enabled. Defaults to false.
  */
  enableLogs?: boolean;
+ /**
+ * An event-processing callback for logs, guaranteed to be invoked after all other log
+ * processors. This allows a log to be modified or dropped before it's sent.
+ *
+ * Note that you must return a valid log from this callback. If you do not wish to modify the log, simply return
+ * it at the end. Returning `null` will cause the log to be dropped.
+ *
+ * @param log The log generated by the SDK.
+ * @returns A new log that will be sent | null.
+ */
+ beforeSendLog?: (log: Log) => Log | null;
  };
 
  /**

packages/core/test/lib/log/index.test.ts

@@ -8,6 +8,7 @@ import {
 import { TestClient, getDefaultTestClientOptions } from '../../mocks/client';
 import * as loggerModule from '../../../src/utils-hoist/logger';
 import { Scope } from '../../../src';
+import type { Log } from '../../../src/types-hoist/log';
 
 const PUBLIC_DSN = 'https://username@domain/123';
 
@@ -187,4 +188,94 @@ describe('_INTERNAL_captureLog', () => {
  _INTERNAL_flushLogsBuffer(client);
  expect(mockSendEnvelope).not.toHaveBeenCalled();
  });
+
+ it('processes logs through beforeSendLog when provided', () => {
+ const beforeSendLog = vi.fn().mockImplementation(log => ({
+ ...log,
+ message: `Modified: ${log.message}`,
+ attributes: { ...log.attributes, processed: true },
+ }));
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalledWith({
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ });
+
+ const logBuffer = _INTERNAL_getLogBuffer(client);
+ expect(logBuffer).toBeDefined();
+ expect(logBuffer?.[0]).toEqual(
+ expect.objectContaining({
+ body: {
+ stringValue: 'Modified: original message',
+ },
+ attributes: expect.arrayContaining([
+ expect.objectContaining({ key: 'processed', value: { boolValue: true } }),
+ expect.objectContaining({ key: 'original', value: { boolValue: true } }),
+ ]),
+ }),
+ );
+ });
+
+ it('drops logs when beforeSendLog returns null', () => {
+ const beforeSendLog = vi.fn().mockReturnValue(null);
+ const recordDroppedEventSpy = vi.spyOn(TestClient.prototype, 'recordDroppedEvent');
+ const loggerWarnSpy = vi.spyOn(loggerModule.logger, 'warn').mockImplementation(() => undefined);
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'test message',
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalled();
+ expect(recordDroppedEventSpy).toHaveBeenCalledWith('before_send', 'log_item', 1);
+ expect(loggerWarnSpy).toHaveBeenCalledWith('beforeSendLog returned null, log will not be captured.');
+ expect(_INTERNAL_getLogBuffer(client)).toBeUndefined();
+
+ recordDroppedEventSpy.mockRestore();
+ loggerWarnSpy.mockRestore();
+ });
+
+ it('emits beforeCaptureLog and afterCaptureLog events', () => {
+ const beforeCaptureLogSpy = vi.spyOn(TestClient.prototype, 'emit');
+ const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, _experiments: { enableLogs: true } });
+ const client = new TestClient(options);
+
+ const log: Log = {
+ level: 'info',
+ message: 'test message',
+ };
+
+ _INTERNAL_captureLog(log, client, undefined);
+
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('beforeCaptureLog', log);
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('afterCaptureLog', log);
+ beforeCaptureLogSpy.mockRestore();
+ });
 });

packages/core/src/client.ts

@@ -623,12 +623,19 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public on(hook: 'close', callback: () => void): () => void;
 
  /**
- * A hook that is called before a log is captured
+ * A hook that is called before a log is captured. This hooks runs before `beforeSendLog` is fired.
  *
  * @returns {() => void} A function that, when executed, removes the registered callback.
  */
  public on(hook: 'beforeCaptureLog', callback: (log: Log) => void): () => void;
 
+ /**
+ * A hook that is called after a log is captured
+ *
+ * @returns {() => void} A function that, when executed, removes the registered callback.
+ */
+ public on(hook: 'afterCaptureLog', callback: (log: Log) => void): () => void;
+
  /**
  * Register a hook on this client.
  */
@@ -777,10 +784,15 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public emit(hook: 'close'): void;
 
  /**
- * Emit a hook event for client before capturing a log
+ * Emit a hook event for client before capturing a log. This hooks runs before `beforeSendLog` is fired.
  */
  public emit(hook: 'beforeCaptureLog', log: Log): void;
 
+ /**
+ * Emit a hook event for client after capturing a log.
+ */
+ public emit(hook: 'afterCaptureLog', log: Log): void;
+
  /**
  * Emit a hook that was previously registered via `on()`.
  */

packages/core/src/logs/index.ts

@@ -62,18 +62,28 @@ export function logAttributeToSerializedLogAttribute(key: string, value: unknown
  * @experimental This method will experience breaking changes. This is not yet part of
  * the stable Sentry SDK API and can be changed or removed without warning.
  */
-export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = getCurrentScope()): void {
+export function _INTERNAL_captureLog(beforeLog: Log, client = getClient(), scope = getCurrentScope()): void {
  if (!client) {
  DEBUG_BUILD && logger.warn('No client available to capture log.');
  return;
  }
 
  const { _experiments, release, environment } = client.getOptions();
- if (!_experiments?.enableLogs) {
+ const { enableLogs = false, beforeSendLog } = _experiments ?? {};
+ if (!enableLogs) {
  DEBUG_BUILD && logger.warn('logging option not enabled, log will not be captured.');
  return;
  }
 
+ client.emit('beforeCaptureLog', beforeLog);
+
+ const log = beforeSendLog ? beforeSendLog(beforeLog) : beforeLog;
+ if (!log) {
+ client.recordDroppedEvent('before_send', 'log_item', 1);
+ DEBUG_BUILD && logger.warn('beforeSendLog returned null, log will not be captured.');
+ return;
+ }
+
  const [, traceContext] = _getTraceInfoFromScope(client, scope);
 
  const { level, message, attributes, severityNumber } = log;
@@ -117,7 +127,7 @@ export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = get
  }
  }
 
- client.emit('beforeCaptureLog', log);
+ client.emit('afterCaptureLog', log);
 }
 
 /**

packages/core/src/server-runtime-client.ts

@@ -57,7 +57,7 @@ export class ServerRuntimeClient<
  _INTERNAL_flushLogsBuffer(client);
  });
 
- this.on('beforeCaptureLog', log => {
+ this.on('afterCaptureLog', log => {
  client._logWeight += estimateLogSizeInBytes(log);
 
  // We flush the logs buffer if it exceeds 0.8 MB

packages/core/src/types-hoist/options.ts

@@ -2,6 +2,7 @@ import type { CaptureContext } from '../scope';
 import type { Breadcrumb, BreadcrumbHint } from './breadcrumb';
 import type { ErrorEvent, EventHint, TransactionEvent } from './event';
 import type { Integration } from './integration';
+import type { Log } from './log';
 import type { TracesSamplerSamplingContext } from './samplingcontext';
 import type { SdkMetadata } from './sdkmetadata';
 import type { SpanJSON } from './span';
@@ -188,6 +189,17 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
  * If logs support should be enabled. Defaults to false.
  */
  enableLogs?: boolean;
+ /**
+ * An event-processing callback for logs, guaranteed to be invoked after all other log
+ * processors. This allows a log to be modified or dropped before it's sent.
+ *
+ * Note that you must return a valid log from this callback. If you do not wish to modify the log, simply return
+ * it at the end. Returning `null` will cause the log to be dropped.
+ *
+ * @param log The log generated by the SDK.
+ * @returns A new log that will be sent | null.
+ */
+ beforeSendLog?: (log: Log) => Log | null;
  };
 
  /**

packages/core/test/lib/log/index.test.ts

@@ -8,6 +8,7 @@ import {
 import { TestClient, getDefaultTestClientOptions } from '../../mocks/client';
 import * as loggerModule from '../../../src/utils-hoist/logger';
 import { Scope } from '../../../src';
+import type { Log } from '../../../src/types-hoist/log';
 
 const PUBLIC_DSN = 'https://username@domain/123';
 
@@ -187,4 +188,94 @@ describe('_INTERNAL_captureLog', () => {
  _INTERNAL_flushLogsBuffer(client);
  expect(mockSendEnvelope).not.toHaveBeenCalled();
  });
+
+ it('processes logs through beforeSendLog when provided', () => {
+ const beforeSendLog = vi.fn().mockImplementation(log => ({
+ ...log,
+ message: `Modified: ${log.message}`,
+ attributes: { ...log.attributes, processed: true },
+ }));
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalledWith({
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ });
+
+ const logBuffer = _INTERNAL_getLogBuffer(client);
+ expect(logBuffer).toBeDefined();
+ expect(logBuffer?.[0]).toEqual(
+ expect.objectContaining({
+ body: {
+ stringValue: 'Modified: original message',
+ },
+ attributes: expect.arrayContaining([
+ expect.objectContaining({ key: 'processed', value: { boolValue: true } }),
+ expect.objectContaining({ key: 'original', value: { boolValue: true } }),
+ ]),
+ }),
+ );
+ });
+
+ it('drops logs when beforeSendLog returns null', () => {
+ const beforeSendLog = vi.fn().mockReturnValue(null);
+ const recordDroppedEventSpy = vi.spyOn(TestClient.prototype, 'recordDroppedEvent');
+ const loggerWarnSpy = vi.spyOn(loggerModule.logger, 'warn').mockImplementation(() => undefined);
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'test message',
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalled();
+ expect(recordDroppedEventSpy).toHaveBeenCalledWith('before_send', 'log_item', 1);
+ expect(loggerWarnSpy).toHaveBeenCalledWith('beforeSendLog returned null, log will not be captured.');
+ expect(_INTERNAL_getLogBuffer(client)).toBeUndefined();
+
+ recordDroppedEventSpy.mockRestore();
+ loggerWarnSpy.mockRestore();
+ });
+
+ it('emits beforeCaptureLog and afterCaptureLog events', () => {
+ const beforeCaptureLogSpy = vi.spyOn(TestClient.prototype, 'emit');
+ const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, _experiments: { enableLogs: true } });
+ const client = new TestClient(options);
+
+ const log: Log = {
+ level: 'info',
+ message: 'test message',
+ };
+
+ _INTERNAL_captureLog(log, client, undefined);
+
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('beforeCaptureLog', log);
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('afterCaptureLog', log);
+ beforeCaptureLogSpy.mockRestore();
+ });
 });

packages/core/src/client.ts

@@ -623,12 +623,19 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public on(hook: 'close', callback: () => void): () => void;
 
  /**
- * A hook that is called before a log is captured
+ * A hook that is called before a log is captured. This hooks runs before `beforeSendLog` is fired.
  *
  * @returns {() => void} A function that, when executed, removes the registered callback.
  */
  public on(hook: 'beforeCaptureLog', callback: (log: Log) => void): () => void;
 
+ /**
+ * A hook that is called after a log is captured
+ *
+ * @returns {() => void} A function that, when executed, removes the registered callback.
+ */
+ public on(hook: 'afterCaptureLog', callback: (log: Log) => void): () => void;
+
  /**
  * Register a hook on this client.
  */
@@ -777,10 +784,15 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public emit(hook: 'close'): void;
 
  /**
- * Emit a hook event for client before capturing a log
+ * Emit a hook event for client before capturing a log. This hooks runs before `beforeSendLog` is fired.
  */
  public emit(hook: 'beforeCaptureLog', log: Log): void;
 
+ /**
+ * Emit a hook event for client after capturing a log.
+ */
+ public emit(hook: 'afterCaptureLog', log: Log): void;
+
  /**
  * Emit a hook that was previously registered via `on()`.
  */

packages/core/src/logs/index.ts

@@ -62,18 +62,28 @@ export function logAttributeToSerializedLogAttribute(key: string, value: unknown
  * @experimental This method will experience breaking changes. This is not yet part of
  * the stable Sentry SDK API and can be changed or removed without warning.
  */
-export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = getCurrentScope()): void {
+export function _INTERNAL_captureLog(beforeLog: Log, client = getClient(), scope = getCurrentScope()): void {
  if (!client) {
  DEBUG_BUILD && logger.warn('No client available to capture log.');
  return;
  }
 
  const { _experiments, release, environment } = client.getOptions();
- if (!_experiments?.enableLogs) {
+ const { enableLogs = false, beforeSendLog } = _experiments ?? {};
+ if (!enableLogs) {
  DEBUG_BUILD && logger.warn('logging option not enabled, log will not be captured.');
  return;
  }
 
+ client.emit('beforeCaptureLog', beforeLog);
+
+ const log = beforeSendLog ? beforeSendLog(beforeLog) : beforeLog;
+ if (!log) {
+ client.recordDroppedEvent('before_send', 'log_item', 1);
+ DEBUG_BUILD && logger.warn('beforeSendLog returned null, log will not be captured.');
+ return;
+ }
+
  const [, traceContext] = _getTraceInfoFromScope(client, scope);
 
  const { level, message, attributes, severityNumber } = log;
@@ -117,7 +127,7 @@ export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = get
  }
  }
 
- client.emit('beforeCaptureLog', log);
+ client.emit('afterCaptureLog', log);
 }
 
 /**

packages/core/src/server-runtime-client.ts

@@ -57,7 +57,7 @@ export class ServerRuntimeClient<
  _INTERNAL_flushLogsBuffer(client);
  });
 
- this.on('beforeCaptureLog', log => {
+ this.on('afterCaptureLog', log => {
  client._logWeight += estimateLogSizeInBytes(log);
 
  // We flush the logs buffer if it exceeds 0.8 MB

packages/core/src/types-hoist/options.ts

@@ -2,6 +2,7 @@ import type { CaptureContext } from '../scope';
 import type { Breadcrumb, BreadcrumbHint } from './breadcrumb';
 import type { ErrorEvent, EventHint, TransactionEvent } from './event';
 import type { Integration } from './integration';
+import type { Log } from './log';
 import type { TracesSamplerSamplingContext } from './samplingcontext';
 import type { SdkMetadata } from './sdkmetadata';
 import type { SpanJSON } from './span';
@@ -188,6 +189,17 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
  * If logs support should be enabled. Defaults to false.
  */
  enableLogs?: boolean;
+ /**
+ * An event-processing callback for logs, guaranteed to be invoked after all other log
+ * processors. This allows a log to be modified or dropped before it's sent.
+ *
+ * Note that you must return a valid log from this callback. If you do not wish to modify the log, simply return
+ * it at the end. Returning `null` will cause the log to be dropped.
+ *
+ * @param log The log generated by the SDK.
+ * @returns A new log that will be sent | null.
+ */
+ beforeSendLog?: (log: Log) => Log | null;
  };
 
  /**

packages/core/test/lib/log/index.test.ts

@@ -8,6 +8,7 @@ import {
 import { TestClient, getDefaultTestClientOptions } from '../../mocks/client';
 import * as loggerModule from '../../../src/utils-hoist/logger';
 import { Scope } from '../../../src';
+import type { Log } from '../../../src/types-hoist/log';
 
 const PUBLIC_DSN = 'https://username@domain/123';
 
@@ -187,4 +188,94 @@ describe('_INTERNAL_captureLog', () => {
  _INTERNAL_flushLogsBuffer(client);
  expect(mockSendEnvelope).not.toHaveBeenCalled();
  });
+
+ it('processes logs through beforeSendLog when provided', () => {
+ const beforeSendLog = vi.fn().mockImplementation(log => ({
+ ...log,
+ message: `Modified: ${log.message}`,
+ attributes: { ...log.attributes, processed: true },
+ }));
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalledWith({
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ });
+
+ const logBuffer = _INTERNAL_getLogBuffer(client);
+ expect(logBuffer).toBeDefined();
+ expect(logBuffer?.[0]).toEqual(
+ expect.objectContaining({
+ body: {
+ stringValue: 'Modified: original message',
+ },
+ attributes: expect.arrayContaining([
+ expect.objectContaining({ key: 'processed', value: { boolValue: true } }),
+ expect.objectContaining({ key: 'original', value: { boolValue: true } }),
+ ]),
+ }),
+ );
+ });
+
+ it('drops logs when beforeSendLog returns null', () => {
+ const beforeSendLog = vi.fn().mockReturnValue(null);
+ const recordDroppedEventSpy = vi.spyOn(TestClient.prototype, 'recordDroppedEvent');
+ const loggerWarnSpy = vi.spyOn(loggerModule.logger, 'warn').mockImplementation(() => undefined);
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'test message',
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalled();
+ expect(recordDroppedEventSpy).toHaveBeenCalledWith('before_send', 'log_item', 1);
+ expect(loggerWarnSpy).toHaveBeenCalledWith('beforeSendLog returned null, log will not be captured.');
+ expect(_INTERNAL_getLogBuffer(client)).toBeUndefined();
+
+ recordDroppedEventSpy.mockRestore();
+ loggerWarnSpy.mockRestore();
+ });
+
+ it('emits beforeCaptureLog and afterCaptureLog events', () => {
+ const beforeCaptureLogSpy = vi.spyOn(TestClient.prototype, 'emit');
+ const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, _experiments: { enableLogs: true } });
+ const client = new TestClient(options);
+
+ const log: Log = {
+ level: 'info',
+ message: 'test message',
+ };
+
+ _INTERNAL_captureLog(log, client, undefined);
+
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('beforeCaptureLog', log);
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('afterCaptureLog', log);
+ beforeCaptureLogSpy.mockRestore();
+ });
 });

packages/core/src/client.ts

@@ -623,12 +623,19 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public on(hook: 'close', callback: () => void): () => void;
 
  /**
- * A hook that is called before a log is captured
+ * A hook that is called before a log is captured. This hooks runs before `beforeSendLog` is fired.
  *
  * @returns {() => void} A function that, when executed, removes the registered callback.
  */
  public on(hook: 'beforeCaptureLog', callback: (log: Log) => void): () => void;
 
+ /**
+ * A hook that is called after a log is captured
+ *
+ * @returns {() => void} A function that, when executed, removes the registered callback.
+ */
+ public on(hook: 'afterCaptureLog', callback: (log: Log) => void): () => void;
+
  /**
  * Register a hook on this client.
  */
@@ -777,10 +784,15 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public emit(hook: 'close'): void;
 
  /**
- * Emit a hook event for client before capturing a log
+ * Emit a hook event for client before capturing a log. This hooks runs before `beforeSendLog` is fired.
  */
  public emit(hook: 'beforeCaptureLog', log: Log): void;
 
+ /**
+ * Emit a hook event for client after capturing a log.
+ */
+ public emit(hook: 'afterCaptureLog', log: Log): void;
+
  /**
  * Emit a hook that was previously registered via `on()`.
  */

packages/core/src/logs/index.ts

@@ -62,18 +62,28 @@ export function logAttributeToSerializedLogAttribute(key: string, value: unknown
  * @experimental This method will experience breaking changes. This is not yet part of
  * the stable Sentry SDK API and can be changed or removed without warning.
  */
-export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = getCurrentScope()): void {
+export function _INTERNAL_captureLog(beforeLog: Log, client = getClient(), scope = getCurrentScope()): void {
  if (!client) {
  DEBUG_BUILD && logger.warn('No client available to capture log.');
  return;
  }
 
  const { _experiments, release, environment } = client.getOptions();
- if (!_experiments?.enableLogs) {
+ const { enableLogs = false, beforeSendLog } = _experiments ?? {};
+ if (!enableLogs) {
  DEBUG_BUILD && logger.warn('logging option not enabled, log will not be captured.');
  return;
  }
 
+ client.emit('beforeCaptureLog', beforeLog);
+
+ const log = beforeSendLog ? beforeSendLog(beforeLog) : beforeLog;
+ if (!log) {
+ client.recordDroppedEvent('before_send', 'log_item', 1);
+ DEBUG_BUILD && logger.warn('beforeSendLog returned null, log will not be captured.');
+ return;
+ }
+
  const [, traceContext] = _getTraceInfoFromScope(client, scope);
 
  const { level, message, attributes, severityNumber } = log;
@@ -117,7 +127,7 @@ export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = get
  }
  }
 
- client.emit('beforeCaptureLog', log);
+ client.emit('afterCaptureLog', log);
 }
 
 /**

packages/core/src/server-runtime-client.ts

@@ -57,7 +57,7 @@ export class ServerRuntimeClient<
  _INTERNAL_flushLogsBuffer(client);
  });
 
- this.on('beforeCaptureLog', log => {
+ this.on('afterCaptureLog', log => {
  client._logWeight += estimateLogSizeInBytes(log);
 
  // We flush the logs buffer if it exceeds 0.8 MB

packages/core/src/types-hoist/options.ts

@@ -2,6 +2,7 @@ import type { CaptureContext } from '../scope';
 import type { Breadcrumb, BreadcrumbHint } from './breadcrumb';
 import type { ErrorEvent, EventHint, TransactionEvent } from './event';
 import type { Integration } from './integration';
+import type { Log } from './log';
 import type { TracesSamplerSamplingContext } from './samplingcontext';
 import type { SdkMetadata } from './sdkmetadata';
 import type { SpanJSON } from './span';
@@ -188,6 +189,17 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
  * If logs support should be enabled. Defaults to false.
  */
  enableLogs?: boolean;
+ /**
+ * An event-processing callback for logs, guaranteed to be invoked after all other log
+ * processors. This allows a log to be modified or dropped before it's sent.
+ *
+ * Note that you must return a valid log from this callback. If you do not wish to modify the log, simply return
+ * it at the end. Returning `null` will cause the log to be dropped.
+ *
+ * @param log The log generated by the SDK.
+ * @returns A new log that will be sent | null.
+ */
+ beforeSendLog?: (log: Log) => Log | null;
  };
 
  /**

packages/core/test/lib/log/index.test.ts

@@ -8,6 +8,7 @@ import {
 import { TestClient, getDefaultTestClientOptions } from '../../mocks/client';
 import * as loggerModule from '../../../src/utils-hoist/logger';
 import { Scope } from '../../../src';
+import type { Log } from '../../../src/types-hoist/log';
 
 const PUBLIC_DSN = 'https://username@domain/123';
 
@@ -187,4 +188,94 @@ describe('_INTERNAL_captureLog', () => {
  _INTERNAL_flushLogsBuffer(client);
  expect(mockSendEnvelope).not.toHaveBeenCalled();
  });
+
+ it('processes logs through beforeSendLog when provided', () => {
+ const beforeSendLog = vi.fn().mockImplementation(log => ({
+ ...log,
+ message: `Modified: ${log.message}`,
+ attributes: { ...log.attributes, processed: true },
+ }));
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalledWith({
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ });
+
+ const logBuffer = _INTERNAL_getLogBuffer(client);
+ expect(logBuffer).toBeDefined();
+ expect(logBuffer?.[0]).toEqual(
+ expect.objectContaining({
+ body: {
+ stringValue: 'Modified: original message',
+ },
+ attributes: expect.arrayContaining([
+ expect.objectContaining({ key: 'processed', value: { boolValue: true } }),
+ expect.objectContaining({ key: 'original', value: { boolValue: true } }),
+ ]),
+ }),
+ );
+ });
+
+ it('drops logs when beforeSendLog returns null', () => {
+ const beforeSendLog = vi.fn().mockReturnValue(null);
+ const recordDroppedEventSpy = vi.spyOn(TestClient.prototype, 'recordDroppedEvent');
+ const loggerWarnSpy = vi.spyOn(loggerModule.logger, 'warn').mockImplementation(() => undefined);
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'test message',
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalled();
+ expect(recordDroppedEventSpy).toHaveBeenCalledWith('before_send', 'log_item', 1);
+ expect(loggerWarnSpy).toHaveBeenCalledWith('beforeSendLog returned null, log will not be captured.');
+ expect(_INTERNAL_getLogBuffer(client)).toBeUndefined();
+
+ recordDroppedEventSpy.mockRestore();
+ loggerWarnSpy.mockRestore();
+ });
+
+ it('emits beforeCaptureLog and afterCaptureLog events', () => {
+ const beforeCaptureLogSpy = vi.spyOn(TestClient.prototype, 'emit');
+ const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, _experiments: { enableLogs: true } });
+ const client = new TestClient(options);
+
+ const log: Log = {
+ level: 'info',
+ message: 'test message',
+ };
+
+ _INTERNAL_captureLog(log, client, undefined);
+
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('beforeCaptureLog', log);
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('afterCaptureLog', log);
+ beforeCaptureLogSpy.mockRestore();
+ });
 });

packages/core/src/client.ts

@@ -623,12 +623,19 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public on(hook: 'close', callback: () => void): () => void;
 
  /**
- * A hook that is called before a log is captured
+ * A hook that is called before a log is captured. This hooks runs before `beforeSendLog` is fired.
  *
  * @returns {() => void} A function that, when executed, removes the registered callback.
  */
  public on(hook: 'beforeCaptureLog', callback: (log: Log) => void): () => void;
 
+ /**
+ * A hook that is called after a log is captured
+ *
+ * @returns {() => void} A function that, when executed, removes the registered callback.
+ */
+ public on(hook: 'afterCaptureLog', callback: (log: Log) => void): () => void;
+
  /**
  * Register a hook on this client.
  */
@@ -777,10 +784,15 @@ export abstract class Client<O extends ClientOptions = ClientOptions> {
  public emit(hook: 'close'): void;
 
  /**
- * Emit a hook event for client before capturing a log
+ * Emit a hook event for client before capturing a log. This hooks runs before `beforeSendLog` is fired.
  */
  public emit(hook: 'beforeCaptureLog', log: Log): void;
 
+ /**
+ * Emit a hook event for client after capturing a log.
+ */
+ public emit(hook: 'afterCaptureLog', log: Log): void;
+
  /**
  * Emit a hook that was previously registered via `on()`.
  */

packages/core/src/logs/index.ts

@@ -62,18 +62,28 @@ export function logAttributeToSerializedLogAttribute(key: string, value: unknown
  * @experimental This method will experience breaking changes. This is not yet part of
  * the stable Sentry SDK API and can be changed or removed without warning.
  */
-export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = getCurrentScope()): void {
+export function _INTERNAL_captureLog(beforeLog: Log, client = getClient(), scope = getCurrentScope()): void {
  if (!client) {
  DEBUG_BUILD && logger.warn('No client available to capture log.');
  return;
  }
 
  const { _experiments, release, environment } = client.getOptions();
- if (!_experiments?.enableLogs) {
+ const { enableLogs = false, beforeSendLog } = _experiments ?? {};
+ if (!enableLogs) {
  DEBUG_BUILD && logger.warn('logging option not enabled, log will not be captured.');
  return;
  }
 
+ client.emit('beforeCaptureLog', beforeLog);
+
+ const log = beforeSendLog ? beforeSendLog(beforeLog) : beforeLog;
+ if (!log) {
+ client.recordDroppedEvent('before_send', 'log_item', 1);
+ DEBUG_BUILD && logger.warn('beforeSendLog returned null, log will not be captured.');
+ return;
+ }
+
  const [, traceContext] = _getTraceInfoFromScope(client, scope);
 
  const { level, message, attributes, severityNumber } = log;
@@ -117,7 +127,7 @@ export function _INTERNAL_captureLog(log: Log, client = getClient(), scope = get
  }
  }
 
- client.emit('beforeCaptureLog', log);
+ client.emit('afterCaptureLog', log);
 }
 
 /**

packages/core/src/server-runtime-client.ts

@@ -57,7 +57,7 @@ export class ServerRuntimeClient<
  _INTERNAL_flushLogsBuffer(client);
  });
 
- this.on('beforeCaptureLog', log => {
+ this.on('afterCaptureLog', log => {
  client._logWeight += estimateLogSizeInBytes(log);
 
  // We flush the logs buffer if it exceeds 0.8 MB

packages/core/src/types-hoist/options.ts

@@ -2,6 +2,7 @@ import type { CaptureContext } from '../scope';
 import type { Breadcrumb, BreadcrumbHint } from './breadcrumb';
 import type { ErrorEvent, EventHint, TransactionEvent } from './event';
 import type { Integration } from './integration';
+import type { Log } from './log';
 import type { TracesSamplerSamplingContext } from './samplingcontext';
 import type { SdkMetadata } from './sdkmetadata';
 import type { SpanJSON } from './span';
@@ -188,6 +189,17 @@ export interface ClientOptions<TO extends BaseTransportOptions = BaseTransportOp
  * If logs support should be enabled. Defaults to false.
  */
  enableLogs?: boolean;
+ /**
+ * An event-processing callback for logs, guaranteed to be invoked after all other log
+ * processors. This allows a log to be modified or dropped before it's sent.
+ *
+ * Note that you must return a valid log from this callback. If you do not wish to modify the log, simply return
+ * it at the end. Returning `null` will cause the log to be dropped.
+ *
+ * @param log The log generated by the SDK.
+ * @returns A new log that will be sent | null.
+ */
+ beforeSendLog?: (log: Log) => Log | null;
  };
 
  /**

packages/core/test/lib/log/index.test.ts

@@ -8,6 +8,7 @@ import {
 import { TestClient, getDefaultTestClientOptions } from '../../mocks/client';
 import * as loggerModule from '../../../src/utils-hoist/logger';
 import { Scope } from '../../../src';
+import type { Log } from '../../../src/types-hoist/log';
 
 const PUBLIC_DSN = 'https://username@domain/123';
 
@@ -187,4 +188,94 @@ describe('_INTERNAL_captureLog', () => {
  _INTERNAL_flushLogsBuffer(client);
  expect(mockSendEnvelope).not.toHaveBeenCalled();
  });
+
+ it('processes logs through beforeSendLog when provided', () => {
+ const beforeSendLog = vi.fn().mockImplementation(log => ({
+ ...log,
+ message: `Modified: ${log.message}`,
+ attributes: { ...log.attributes, processed: true },
+ }));
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalledWith({
+ level: 'info',
+ message: 'original message',
+ attributes: { original: true },
+ });
+
+ const logBuffer = _INTERNAL_getLogBuffer(client);
+ expect(logBuffer).toBeDefined();
+ expect(logBuffer?.[0]).toEqual(
+ expect.objectContaining({
+ body: {
+ stringValue: 'Modified: original message',
+ },
+ attributes: expect.arrayContaining([
+ expect.objectContaining({ key: 'processed', value: { boolValue: true } }),
+ expect.objectContaining({ key: 'original', value: { boolValue: true } }),
+ ]),
+ }),
+ );
+ });
+
+ it('drops logs when beforeSendLog returns null', () => {
+ const beforeSendLog = vi.fn().mockReturnValue(null);
+ const recordDroppedEventSpy = vi.spyOn(TestClient.prototype, 'recordDroppedEvent');
+ const loggerWarnSpy = vi.spyOn(loggerModule.logger, 'warn').mockImplementation(() => undefined);
+
+ const options = getDefaultTestClientOptions({
+ dsn: PUBLIC_DSN,
+ _experiments: { enableLogs: true, beforeSendLog },
+ });
+ const client = new TestClient(options);
+
+ _INTERNAL_captureLog(
+ {
+ level: 'info',
+ message: 'test message',
+ },
+ client,
+ undefined,
+ );
+
+ expect(beforeSendLog).toHaveBeenCalled();
+ expect(recordDroppedEventSpy).toHaveBeenCalledWith('before_send', 'log_item', 1);
+ expect(loggerWarnSpy).toHaveBeenCalledWith('beforeSendLog returned null, log will not be captured.');
+ expect(_INTERNAL_getLogBuffer(client)).toBeUndefined();
+
+ recordDroppedEventSpy.mockRestore();
+ loggerWarnSpy.mockRestore();
+ });
+
+ it('emits beforeCaptureLog and afterCaptureLog events', () => {
+ const beforeCaptureLogSpy = vi.spyOn(TestClient.prototype, 'emit');
+ const options = getDefaultTestClientOptions({ dsn: PUBLIC_DSN, _experiments: { enableLogs: true } });
+ const client = new TestClient(options);
+
+ const log: Log = {
+ level: 'info',
+ message: 'test message',
+ };
+
+ _INTERNAL_captureLog(log, client, undefined);
+
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('beforeCaptureLog', log);
+ expect(beforeCaptureLogSpy).toHaveBeenCalledWith('afterCaptureLog', log);
+ beforeCaptureLogSpy.mockRestore();
+ });
 });