@beforeyoubid/logger-adapter

LogDNA Logger Adapter

This is a platform logger module that is able to support multiple logging scenarios.

• A console log wrapper so it can send all logs from the native console object to LogDNA.
• A Winston log wrapper logger which output better colour and we can send log messages to LogNDA.

This module is designed to work on a native node runtime and in a Lambda environment. For Lambda, please see the Flush All Messages section below.

Console Logger vs. Winston Logger

• Dispite that console.log() is not a recommended approach to be used for frontend application but it's fine to use in the backend. Here are some limitations:
  • The native console log object doesn't support the LOG_LEVEL. For example, you may not want console.debug() to show debugging info on a production server.
  • Doesn't support log colour
  • Doesn't show datetime which is hard to make sense of
  • Doesn't support to send log to external services
• Console Logger wraps over the existing console object as a pathway to adopting a logger object.
  • Log levels
  • Send to external service
• Winston Logger solves all limitations described above

If you are using console.log on the existing code base and not ready to switch to Winston logger just yet, this module can also helps you out as well.

1) Use Console Logger

  yarn add @beforeyoubid/logger-adapter

Activate it

We follow 12-factors and we can enable and send log to LogDNA by supplying LOGDNA_KEY as part of the environment variables.

  LOGDNA_KEY=xxxxxxyyyyyyyzzzzzzz

Please note that on your local, you can set LOGDNA_KEY= to disable sending logs to LogDNA. Supply LOG_LEVEL as part of the environment variable.

Additionally, you can keep LOGDNA_KEY value the same way you set for other environments but can disable sending logs by setting LOGDNA_ENABLED=false in your env variables.

For a non-lambda environment

    import { consoleLogger } from '@beforeyoubid/logger-adapter';
    consoleLogger.init();

    // Don't need to call consoleLogger.flushAll(), logdna object has default flush interval interval at 250ms

Lambda: Use with an Aync Handler

  import { consoleLogger, flushAll } from '@beforeyoubid/logger-adapter';
  consoleLogger.init();

  // Ensure the we flush all messages before Lambda function gets terminated
  const yourLambdaHandler = async (event, context) => {
    try {
      console.debug('Sample debug log - this message only show up when LOG_LEVEL is set to "debug"')

      const result = await yourNormalProcess();

      await flushAll(); // Trigger to flush all messages

      return result;
    } catch (e) {
      // handle error
      await flushAll(); // Trigger to flush all messages

      // Throw or send result as usual
      throw e;

      // Or handle it nicely
      // return unsuccessfulResponse;
    }
  }

Lambda: Use with a Callback Handler

  import { consoleLogger, flushAll } from '@beforeyoubid/logger-adapter';
  consoleLogger.init();

  const yourLambdaHandler = (event, context, callback) => {
    try {
      console.debug('Sample debug log - this message only show up when LOG_LEVEL is set to "debug"')

      const result = yourNormalProcess();

      callback(null, yourNormalResponseObject);

      flushAll(); // Trigger to flush all messages
    } catch (e) {

      // Ensure the we flush all messages before Lambda function gets terminated
      flushAll(); // Trigger to flush all messages

      // Call a callback with error
      callback(yourErrorObject);

      // Or return unsuccessful response
      // https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-output-format
      // callback(null, unsuccessfulResponse);
    }
  }

Lambda: Use a handler wrapper for Serverless Express

  import { consoleLogger, ensureFlushAll } from '@beforeyoubid/logger-adapter';
  consoleLogger.init();

  export default ensureFlushAll(graphqlHandler);

Lambda: Use with a Callback Handler (Apollo GraphQL Handler)

  import { consoleLogger, ensureFlushAllCallback } from '@beforeyoubid/logger-adapter';
  consoleLogger.init();

  // Existing graphql hander - it uses callback signature
  const graphqlHandler = server.createHandler({
    cors: {
      origin: '*',
      allowedHeaders: ['x-api-token', 'Authorization'],
      methods: ['GET', 'POST'],
    },
  });

  export default ensureFlushAllCallback(graphqlHandler);

2) Use Winston Logger

  yarn add @beforeyoubid/logger-adapter

Activate it

We follow 12-factors and we can enable and send log to LogDNA by supplying LOGDNA_KEY as part of the environment variables.

  LOGDNA_KEY=xxxxxxyyyyyyyzzzzzzz

Please note that on your local, you can set LOGDNA_KEY= to disable sending logs to LogDNA. Supply LOG_LEVEL as part of the environment variable.

For a non-lambda environment

    import { logger } from '@beforeyoubid/logger-adapter';

    logger.debug('This message only show up when LOG_LEVEL is set to "debug"')
    logger.info('This message only show up when LOG_LEVEL is set to "info"')

Lambda: Use with an Aync Handler

  import { logger, flushAll } from '@beforeyoubid/logger-adapter';

  const yourLambdaHandler = async (event, context) => {
    try {
      logger.debug('Sample debug log - this message only show up when LOG_LEVEL is set to "debug"')

      const result = await yourNormalProcess();

      // Ensure the we flush all messages before Lambda function gets terminated
      await flushAll();

      return result;
    } catch (e) {
      // Ensure the we flush all messages before Lambda function gets terminated
      await flushAll(); // Trigger to flush all messages

      // Throw or send result as usual
      throw e;

      // Or handle it nicely
      // return unsuccessfulResponse;
    }
  }

Lambda: Use with a Callback Handler

  import { logger, flushAll } from '@beforeyoubid/logger-adapter';

  const yourLambdaHandler = (event, context, callback) => {
    try {
      logger.debug('Sample debug log - this message only show up when LOG_LEVEL is set to "debug"')

      const result = yourNormalProcess();

      callback(null, yourNormalResponseObject);

      // Ensure the we flush all messages before Lambda function gets terminated
      flushAll(); // Trigger to flush all messages
    } catch (e) {
      // Ensure the we flush all messages before Lambda function gets terminated
      flushAll(); // Trigger to flush all messages

      // Call a callback with error
      callback(yourErrorObject);

      // Or return unsuccessful response
      // https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html#api-gateway-simple-proxy-for-lambda-output-format
      // callback(null, unsuccessfulResponse);
    }
  }

Flush All Messages

LogDNA puts messages in the buffer and push out every 250ms. If Lambda is terminated before some of these intervals, it's likely that some of message logs are not sent to LogDNA.

We just need to ensure that after we've completed the business logic and before the Lambda function is terminated, we flush all messages. We can just call a LogDNA flushAll() function and this module export this logic for us to use. Depending on how your Lambda handler is set up, but there are three variances we have observed.

1. Async handler
2. Async handler but use Serverless Express framework
3. Apollo non-async handler which is created by a createHandler() function

Please see usage examples from the above sections