LoggerService.md

LoggerService

Provides logging and integrations with our monitoring tools.

For logging we use Winston. Errors will also be sent to Sentry and Lumigo if those are configured.

Usage

The logger exposes various methods that you can pass messages or objects to for logging:

import lambdaWrapper, { LoggerService } from '@comicrelief/lambda-wrapper';

export default lambdaWrapper.wrap(async (di) => {
  const logger = di.get(LoggerService);

  // general log message
  logger.info('Doing something');

  // tag the trace so we can find certain tracess more easily in Epsagon
  logger.label('flag');
  logger.metric('transactionId', value);

  try {
    // do something that might throw an error...
  } catch (error) {
    // log the error and flag the trace on Epsagon and Sentry
    logger.error(error);

    // alternatively, use `warning` if this error is not relevant in staging
    // (see Soft Warnings below)
    logger.warning(error);
  }
});

Configuration

Soft warnings

The warning method is equivalent to error by default, but can be switched to use info by setting LOGGER_SOFT_WARNING=1 in the environment.

This is handy for muting certain errors in staging, where we expect our integration tests to cause a lot of errors deliberately that would otherwise spam us with Epsagon alerts.

Lumigo

To configure Lumigo, either enable auto-tracing, or set the LUMIGO_TRACER_TOKEN environment variable.

Sentry

To configure Sentry, set the following environment variables:

• RAVEN_DSN – your Sentry DSN URL