Create README.md

README.md

@@ -0,0 +1,60 @@
+# logger
+
+This package provides the logging configuration typically used in Safe Security.
+
+## Motivation
+
+Currently in Safe Security, all the services that require logging functionality imported a library & configured it as per the service needs.
+Although this seems _okay_ initially, it becomes a challenge to do this across multiple services as care needs to be taken to keep the 
+dependency versions consistent across, code reusability takes a back seat since the configuration is duplicated everywhere, and is prone to human errors.
+
+In order to solve this problem, the `winston` library used currently has been encapsulated in this package along with the desired defaults set up so that 
+the client does not have to worry about setting up a verbose configuration in multiple files.
+
+## Installation
+```bash
+npm install logger-safe-security
+```
+
+```bash
+yarn add logger-safe-security
+```
+
+## Usage
+The introduction of this package makes it very easy for clients to consume & leverage the logging capabilities.
+
+In Javascript:
+```js
+const { logger } = require("logger-safe-security");
+logger.info("Hello world!");
+```
+
+In Typescript:
+```js
+import { logger } from "logger-safe-security";
+logger.info("Hello world!");
+```
+
+Additionally, one can create child loggers inherited from the parent/package-default to pass specific metadata. 
+One such use case would be to add `service` metadata while importing it within the context of a service. For example:
+```js
+import { logger } from "logger-safe-security";
+const serviceLogger = logger.child({ service: "sample" });
+serviceLogger.info("This log line will include service metadata");
+```
+
+## Definition
+The logger exported as part of this package contains the following definition:
+- Log format: 
+  - The default log format is set to `JSON`. Hence, all the log messages will be represented (printed) as JSON objects.
+  - Timestamp will be added to all log lines in `yyyy-MM-dd'T'HH:mm:ss.SSSZ` format.
+  - Application errors will be captured in the logs.
+  - String interpolation is supported.
+- Log level: 
+  - The defeault log level is `INFO`.
+- Transports:
+  - All logs will be written to `Console` by default.
+  - Exceptions & Promise Rejections will be handled & written to `Console` as well.
+- Metadata:
+  - `{ "type" : "application" }` is added as default metadata to easily identify application logs. This can further be extended to differentiate 
+  from audit logs and add parsing/filtering rules (for e.g. in Datadog) as needed.

lib/index.d.ts

@@ -1,3 +1,2 @@
 import winston from "winston";
-declare const logger: winston.Logger;
-export default logger;
+export declare const logger: winston.Logger;

lib/index.js

@@ -3,9 +3,10 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
     return (mod && mod.__esModule) ? mod : { "default": mod };
 };
 Object.defineProperty(exports, "__esModule", { value: true });
+exports.logger = void 0;
 const winston_1 = __importDefault(require("winston"));
 const { combine, errors, timestamp, splat, json } = winston_1.default.format;
-const logger = winston_1.default.createLogger({
+exports.logger = winston_1.default.createLogger({
     // default log level is "info"
     level: "info",
     // combining multiple formats to get the desired output
@@ -30,4 +31,3 @@ const logger = winston_1.default.createLogger({
     // generic metadata applied to all logs
     defaultMeta: { type: "application" }
 });
-exports.default = logger;