feat: Update logger to use metadata (#12)

Author: prathap-safe

README.md

@@ -59,3 +59,4 @@ The logger exported as part of this package contains the following definition:
 - 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.
+  - Additionally, all other metadata passed to the log messages will be stored under `metadata` property for easy identification & grouping.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "logger-safe-security",
-  "version": "1.1.7",
+  "version": "1.1.8",
   "description": "Custom logging framework used in SAFE",
   "main": "lib/index.js",
   "types": "lib",

src/index.ts

@@ -1,6 +1,6 @@
 import winston from "winston";
 
-const { combine, errors, timestamp, splat, json } = winston.format;
+const { combine, errors, timestamp, splat, json, metadata } = winston.format;
 
 export const levels = winston.config.npm.levels;
 
@@ -24,11 +24,16 @@ export const createLogger = (
             // required to log errors thrown by the application; ignored otherwise
             errors({ stack: true }),
 
+            // adds timestamp to all log messages
+            timestamp(),
+
             // enables string interpolation of messages
             splat(),
 
-            // adds timestamp to all log messages
-            timestamp(),
+            // moves all the other fields in the message to `metadata` property
+            metadata({
+                fillExcept: ["message", "level", "timestamp", "service", "type"]
+            }),
 
             // default log format is JSON
             json()

test/index.test.js

@@ -1,5 +1,5 @@
-const { logger } = require("logger-safe-security").default;
-const appLogger = logger.child({ service: "sample" });
+const { createLogger } = require("logger-safe-security");
+const logger = createLogger({ service: "sample" });
 
-logger.info("This is a parent logger");
-appLogger.info("This is a child logger");
+logger.info("This is a sample logger");
+logger.info("This is a sample logger with more information", { planet: "Earth" });

test/index.test.ts

@@ -1,5 +1,5 @@
-import { logger } from "logger-safe-security";
-const appLogger = logger.child({ service: "sample" });
+import { createLogger } from "logger-safe-security";
+const logger = createLogger({ service: "sample" });
 
-logger.info("This is a parent logger");
-appLogger.info("This is a child logger");
+logger.info("This is a sample logger");
+logger.info("This is a sample logger with more information", { planet: "Earth" });