Set Up Logs

With Sentry Structured Logs, you can send text based log information from your applications to Sentry. Once in Sentry, these logs can be viewed alongside relevant errors, searched by text-string, or searched using their individual attributes.

Requirements

Logs for JavaScript are supported in Sentry JavaScript SDK version 9.17.0 and above.

Setup

To enable logging, you need to initialize the SDK with the _experiments.enableLogs option set to true.

Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0",
  // Enable logs to be sent to Sentry
  _experiments: { enableLogs: true },
});

Usage

Once the feature is enabled on the SDK and the SDK is initialized, you can send logs using the Sentry.logger APIs.

The Sentry.logger namespace exposes six methods that you can use to log messages at different log levels: trace, debug, info, warn, error, and fatal.

Aside from the primary logging methods, we've provided a format text function, Sentry.logger.fmt, that you can use to insert properties into to your log entries.

These properties will be sent to Sentry, and can be searched from within the Logs UI, and even added to the Logs views as a dedicated column.

const { logger } = Sentry;

logger.error(logger.fmt`Uh on, something broke, here's the error: '${error}'`);
logger.info(logger.fmt`'${user.username}' added '${product.name}' to cart.`);

You can also pass additional attributes directly to the logging functions, avoiding the need to use the fmt function.

const { logger } = Sentry;

logger.trace("Starting database connection", { database: "users" });
logger.debug("Cache miss for user", { userId: 123 });
logger.info("Updated profile", { profileId: 345 });
logger.warn("Rate limit reached for endpoint", {
  endpoint: "/api/results/",
  isEnterprise: false,
});
logger.error("Failed to process payment", {
  orderId: "order_123",
  amount: 99.99,
});
logger.fatal("Database connection pool exhausted", {
  database: "users",
  activeConnections: 100,
});

You can also avoid using the fmt function by formatting the log message via a printf-like format string and arguments.

This follows the same structure as the util.format Node.js standard library function.

Sentry.logger.info("User %s logged in successfully", ["John Doe"]);
Sentry.logger.warn("Failed to load user %s data", ["John Doe"], {
  errorCode: 404,
});
Sentry.logger.error(
  "Failed to process payment. Order: %s. Amount: %d. Details: %o",
  ["order_123", 99.99, paymentDetailsObject]
);

Integrations

Console Logging Integration

You can also configure the SDK to send logs via the JavaScript console object, using the SDK's consoleLoggingIntegration.

Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0",
  integrations: [
    // send console.log, console.error, and console.warn calls as logs to Sentry
    Sentry.consoleLoggingIntegration({ levels: ["log", "error", "warn"] }),
  ],
});

The consoleLoggingIntegration accepts a levels option, which is an array of console method names to log. By default the integration will log calls from console.debug, console.info, console.warn, console.error, console.log, console.assert, and console.trace.

Winston Integration

In 9.13.0 and above of the JavaScript SDKs, we've added support to send logs via the winston logging library.

const winston = require("winston");
const Transport = require("winston-transport");

const SentryWinstonTransport = Sentry.createSentryWinstonTransport(Transport);

const logger = winston.createLogger({
  transports: [new SentryWinstonTransport()],
});

The createSentryWinstonTransport method accepts a levels option, which allows you to filter which levels are sent to Sentry. By default all levels are logged.

const SentryWinstonTransport = Sentry.createSentryWinstonTransport(Transport, {
  // Only capture error and warn logs
  levels: ["error", "warn"],
});

Options

beforeSendLog

To filter logs, or update them before they are sent to Sentry, you can use the _experiments.beforeSendLog option.

Sentry.init({
  dsn: "https://examplePublicKey@o0.ingest.sentry.io/0",
  _experiments: {
    enableLogs: true,
    beforeSendLog: (log) => {
      if (log.level === "info") {
        // Filter out all info logs
        return null;
      }

      return log;
    },
  },
});

The beforeSendLog function receives a log object, and should return the log object if you want it to be sent to Sentry, or null if you want to discard it.

The log object has the following properties:

• level: (string - one of trace, debug, info, warn, error, fatal) The log level.
• message: (string) The message to be logged.
• timestamp: (number) The timestamp of the log.
• attributes: (object) The attributes of the log.