sdk-logs

a simple and opinionated logging library. plays well with aws lambda + cloudwatch.

features

• distinguish different priorities of logs with standard levels
  • i.e., log.debug, log.info, log.warn, and log.error
• filter which levels of log to emit
  • i.e., choose based on environment whether to emit all logs or skip some of the logs
• utilizes console.warn and console.log under the hood
  • which ensures that the aws cloudwatch requestId is present on each log message automatically
• formats log metadata based on environment
  • i.e., stringify in local environments to reduce visual noise
  • i.e., don't stringify in aws-lambda environment for optimal cloudwatch parsing

installation

npm install --save sdk-logs

usage

init

// e.g., in `src/utils/log.ts
import { generateLogMethods } from 'sdk-logs';

export const log = generateLogMethods();

use in code

import { log } from '../utils/log';

log.error(`the sky is falling and we're loosing money!`, metadata); // use `.error` when you want someone to respond immediately, even if its 4am

log.warn(`this shouldn't be happening and should be looked at asap`, metadata); // use `.warn` when you want someone to look at it asap, but not wake up in the middle of the night

log.info(`we either want to or should keep track of this`, metadata); // use `.info` for anything we may be interested in knowing about

log.debug(`this will help debug if things go wrong`, metadata); // use this for any information that could help debug when things go wrong (e.g., request/response data)

cloudwatch outlet

for environments without automatic log collection (e.g., non-Lambda compute), you can forward logs directly to CloudWatch:

import * as sdkAwsCloudwatch from '@aws-sdk/client-cloudwatch-logs';
import { genCloudwatchOutlet, genLogMethods } from 'sdk-logs';

const outlet = genCloudwatchOutlet(
  { region: 'us-east-1' },
  { cloudwatch: { sdk: sdkAwsCloudwatch } },
);

const log = genLogMethods({ outlets: [outlet] });

note: the AWS SDK is injected via context to keep it as a peer dependency. install it separately:

npm install --save @aws-sdk/client-cloudwatch-logs