ps-chronicle

A logger package which is PS specific and uses winston internally. It is used to create logs in 2 formats -> JSON or Simple. The default format is JSON. The log levels allowed are : error, wspayload, info, warn, debug. The timestamp is GMT + 0(London timezone)

installation

npm i ps-chronicle

usage

Step 1) Import/require package

const { Logger, setRequestId } = require('ps-chronicle');

Step 2) create context - once per file/class . All three fields in the context object are optional. This logger is PS specific so only these three context properties can be set : "fileName" , "customerName" , "format". If format is not given then the default format will be "json",

const context = {
	fileName: 'app.js',
	customerName: 'SurveyCustomer',
	format: 'json',
};

Step 3) Initialize the object through "Logger" constructor once per file with the context object and the highest log level. If highest log level is not set during initialization, then by default it will take "debug"

var logger = new Logger(context, 'debug');

Step 4) Set requestID per lambda. This request id can be obtained from context object of the lambda. For more information please visit https://docs.aws.amazon.com/lambda/latest/dg/nodejs-context.html

setRequestId(context.awsRequestId);

Step 5) Please write method name for each message . If the log level defined in the log() function is not in the scope then the default log level ,i.e info is set. log() function parameters : i. log level ii. message iii. after above two parameters you can give n number of parameters. All will be the part of key: additionalinfo , which is an array.

function sum(a, b) {
	logger.log('INFO', 'methodName- sum() -> testing  info logger ');
	logger.log('silly', 'methodName- sum() ->testing silly logger '); //silly is not in scope so default log level is set -> info

	logger.log(
		'error',
		'methodName- sum() -> testing error logger ',
		{ tags: 'HEADERS', headers: event.headers },
		{ tags: 'BODY', body: event.body }
	);
	logger.log(
		'wspayload',
		'methodName- sum() -> testing simple wspayload logger ',
		{ tags: 'HEADERS', headers: event.headers },
		{ tags: 'BODY', body: event.body }
	);
	logger.log(
		'warn',
		'methodName- sum() ->testing simple warn logger ',
		{ tags: 'HEADERS', headers: event.headers },
		{ tags: 'BODY', body: event.body }
	);
	logger.log(
		'debug',
		'methodName- sum() -> testing simple debug logger ',
		{ tags: 'HEADERS', headers: event.headers },
		{ tags: 'BODY', body: event.body }
	);
	//rest of the code
}

Additional methods:: Filtering logs and sending it to S3:

The below function is used to filter logs with respect to request ID and then sending those logs to S3 provided bucket should be present. PARAMS USED :

1. logGroupName : context object for lambda has logGroupName . Please visit the link for more reference https://docs.aws.amazon.com/lambda/latest/dg/nodejs-context.html
2. region : region where the log is present. Bucket should also be present in the same region
3. requestId : context object for lambda has awsRequestId . Please visit the link for more reference https://docs.aws.amazon.com/lambda/latest/dg/nodejs-context.html
4. logStreamName : context object for lambda has logStreamName . Please visit the link for more reference https://docs.aws.amazon.com/lambda/latest/dg/nodejs-context.html
5. startTime : The epoch time in millisecond . Visit https://www.epochconverter.com/
6. endTime : The epoch time in millisecond . Visit https://www.epochconverter.com/
7. bucket : The name of the bucket in which the filtered logs should be stored
8. folderStructure : The folder structure in which the logs should be stored inside the bucket,
9. appName : The app name for which this method is being used

let params = {
	logGroupName: context.logGroupName,
	region: process.env.AWS_REGION,
	requestId: context.awsRequestId,
	logStreamName: context.logStreamName,
	startTime: 1609088325000,
	endTime: 1609174725000,
	bucket: 'log-export-bucket-demo',
	folderStructure: 'config/jobs/1075/export',
	appName: 'PS_AUTOMATION',
};
const response = await filterLogToS3(params);

RESPONSE ::

1. If Successful - { "responseCode":200, "responseBody":{ "Bucket":"log-export-bucket-demo", "Key":"config/jobs/1075/export/PS_AUTOMATION_7666e842-ef43-40a5-81b6-56ceb4cc4f9a_29-12-2020 1:1:16", "ETag":""2db336acb2a5c30a6f14e49a7af6e89e"" } }

2. If some error occurred - responseCode : 500 responseBody : error message or Internal Server Error

3. If bucket not found - responseCode : 404 responseBody : 'Bucket : ' {$bucketName} ' does not exist'