AWS Lambda Logging Library for Node.js

The library offers a straightforward logging solution for Node.js-based AWS Lambda functions, requiring no external dependencies.

const { logger } = require("@baselime/lambda-logger");

logger.info("This is an informational message", {
  operation: "copy-paste-replace",
  count: 9000,
});

The library provides an object that includes four logging functions - info, warn, debug, and error - enabling you to log messages with varying levels of severity. By setting the LOG_LEVEL environment variable, you can control the visibility of the logs. The library is incredibly easy to use, with no external dependencies. It enhances console.log with useful defaults.

Installation

npm install @baselime/lambda-logger

Usage

const { logger } = require("@baselime/lambda-logger");

logger.info("This is an informational message", { payload: { foo: "bar" } });
logger.warn("This is a warning message", { payload: { foo: "bar" } });
logger.debug("This is a debug message", { payload: { foo: "bar" } });
logger.error("This is an error message", { payload: { foo: "bar" } });

By default, the library only prints logs with a severity level of info or higher. However, you can control the logging level by setting the LOG_LEVEL environment variable to one of the following values:

• DEBUG: All log messages will be printed.
• INFO (default): Only messages with a severity level of info, warn, or error will be printed.
• WARN: Only messages with a severity level of warn or error will be printed.
• ERROR: Only messages with a severity level of error will be printed.

Additionally, you can use the wrap method to instrument your AWS Lambda function and gain visibility of its trigger event and response, which can be helpful when debugging.

Example

const { wrap, logger } = require("@baselime/lambda-logger");

exports.handler = wrap(async (event, context) => {
  logger.info("Lambda function started");
  try {
    const result = await someAsyncFunction();
    logger.debug("Result", result);
    return result;
  } catch (error) {
    logger.error("Error", error);
    throw error;
  }
});

Middy

We also support Middy The lambda middleware framework.

import { Baselime, logger } from "@baselime/lambda-logger";
import middy from "@middy/core";

exports.handler = middy()
  .use(Baselime())
  .handler(function (e, context) {
    const requests = e.Records.map((el) =>
      Buffer.from(el.kinesis.data, "base64").toString("utf-8")
    );
    logger.info("The events to stream", requests);
  });

Contributing

If you would like to contribute to the development of this library, please submit a pull request on GitHub.

License

This library is licensed under the MIT License. See the LICENSE file for details.