fix(readme): add details about new ecs format

AUT-2249

Co-authored-by: Daniel Gergacz <[email protected]>

Author: akapa

README.md

@@ -9,9 +9,21 @@ It has the same namespace based enabling/disabling mechanism as [debug].
 npm install @emartech/json-logger
 ```
 
+### Usage
 
+Since 8.0.0, by default ECS fields will be used when logging. 
 
-### Usage
+If for reason you still need the old format, you need to override the `outputFormat` config.
+`configure` will apply this setting globally, for all instances of the logger.
+
+```javascript
+const { createLogger } = require('@emartech/json-logger');
+
+createLogger.configure({
+  outputFormat: 'legacy'
+});
+
+```
 
 #### Script
 
@@ -22,13 +34,15 @@ const mongoLogger = createLogger('mongo');
 const redisLogger = createLogger('redis');
 
 redisLogger.info('connected', { domain: 'yahoo' });
-// {"name":"redis","action":"connected","level":30,"time":"2016-08-15T08:50:23.566Z","domain":"yahoo"}
+// ECS format: {"event":{"action":"connected"},"log":{"logger":"redis","level":30},"@timestamp":"2016-08-15T08:50:23.566Z","domain":"yahoo"}
+// Legacy format: {"name":"redis","action":"connected","level":30,"time":"2016-08-15T08:50:23.566Z","domain":"yahoo"}
 
 mongoLogger.info('connected', { domain: 'google' });
 // no output, because 'mongo' is not within namespaces (process.env.DEBUG)
 
 redisLogger.fromError('query', new Error('Unauthorized'), { problem: 'missmatch' });
-// {"name":"redis","action":"query","level":50,"time":"2016-08-15T08:50:23.569Z","error_name":"Error","error_stack":"Error: Unauthorized\n    at Object.<anonymous> (/home/blacksonic/workspace/bunyan-debug/example.js:15:32)\n    at Module._compile (module.js:541:32)\n    at Object.Module._extensions..js (module.js:550:10)\n    at Module.load (module.js:458:32)\n    at tryModuleLoad (module.js:417:12)\n    at Function.Module._load (module.js:409:3)\n    at Module.runMain (module.js:575:10)\n    at run (bootstrap_node.js:352:7)\n    at startup (bootstrap_node.js:144:9)\n    at bootstrap_node.js:467:3","error_message":"Unauthorized","problem":"missmatch"}
+// ECS format: {"event":{"action":"query"},"log":{"logger":"redis","level":50},"@timestamp":"2016-08-15T08:50:23.569Z","error":{"type":"Error","message":"Unauthorized","stack_trace":"..."},"problem":"mismatch"}
+// Legacy format: {"name":"redis","action":"query","level":50,"time":"2016-08-15T08:50:23.569Z","error_name":"Error","error_stack":"Error: Unauthorized\n    at Object.<anonymous> (/home/blacksonic/workspace/bunyan-debug/example.js:15:32)\n    at Module._compile (module.js:541:32)\n    at Object.Module._extensions..js (module.js:550:10)\n    at Module.load (module.js:458:32)\n    at tryModuleLoad (module.js:417:12)\n    at Function.Module._load (module.js:409:3)\n    at Module.runMain (module.js:575:10)\n    at run (bootstrap_node.js:352:7)\n    at startup (bootstrap_node.js:144:9)\n    at bootstrap_node.js:467:3","error_message":"Unauthorized","problem":"missmatch"}
 ```
 
 #### Class
@@ -103,10 +117,12 @@ const { createLogger } = require('@emartech/json-logger');
 const redisLogger = createLogger('redis');
 
 redisLogger.info('connected', { domain: 'yahoo' });
-// {"name":"redis","action":"connected","level":30,"time":"2016-08-15T08:50:23.566Z","domain":"yahoo"}
+// ECS format: {"event":{"action":"connected"},"log":{"logger":"redis","level":30},"@timestamp":"2016-08-15T08:50:23.566Z","domain":"yahoo"}
+// Legacy format: {"name":"redis","action":"connected","level":30,"time":"2016-08-15T08:50:23.566Z","domain":"yahoo"}
 
 redisLogger.info('connected');
-// {"name":"redis","action":"connected","level":30,"time":"2016-08-15T08:50:23.566Z"}
+// ECS format: {"event":{"action":"connected"},"log":{"logger":"redis","level":30},"@timestamp":"2016-08-15T08:50:23.566Z"}
+// Legacy format: {"name":"redis","action":"connected","level":30,"time":"2016-08-15T08:50:23.566Z"}
 ```
 
 By default displays the namespace of the instance (`name`), the current time in ISO8601 format (`time`),
@@ -144,7 +160,8 @@ const { createLogger } = require('@emartech/json-logger');
 const redisLogger = createLogger('redis');
 
 redisLogger.fromError('query', new Error('Unauthorized'), { problem: 'missmatch' });
-// {"name":"redis","action":"query","level":50,"time":"2016-08-15T08:50:23.569Z","error_name":"Error","error_stack":"Error: Unauthorized\n    at Object.<anonymous> (/home/blacksonic/workspace/bunyan-debug/example.js:15:32)\n    at Module._compile (module.js:541:32)\n    at Object.Module._extensions..js (module.js:550:10)\n    at Module.load (module.js:458:32)\n    at tryModuleLoad (module.js:417:12)\n    at Function.Module._load (module.js:409:3)\n    at Module.runMain (module.js:575:10)\n    at run (bootstrap_node.js:352:7)\n    at startup (bootstrap_node.js:144:9)\n    at bootstrap_node.js:467:3","error_message":"Unauthorized","problem":"missmatch"}
+// ECS format: {"event":{"action":"query"},"log":{"logger":"redis","level":50},"@timestamp":"2016-08-15T08:50:23.569Z","error":{"type":"Error","message":"Unauthorized","stack_trace":"..."},"problem":"mismatch"}
+// Legacy format: {"name":"redis","action":"query","level":50,"time":"2016-08-15T08:50:23.569Z","error_name":"Error","error_stack":"Error: Unauthorized\n    at Object.<anonymous> (/home/blacksonic/workspace/bunyan-debug/example.js:15:32)\n    at Module._compile (module.js:541:32)\n    at Object.Module._extensions..js (module.js:550:10)\n    at Module.load (module.js:458:32)\n    at tryModuleLoad (module.js:417:12)\n    at Function.Module._load (module.js:409:3)\n    at Module.runMain (module.js:575:10)\n    at run (bootstrap_node.js:352:7)\n    at startup (bootstrap_node.js:144:9)\n    at bootstrap_node.js:467:3","error_message":"Unauthorized","problem":"missmatch"}
 ```
 
 ##### JsonLogger.prototype.warnFromError(action, data)
@@ -166,7 +183,8 @@ const timer = redisLogger.timer();
 // heavy task
 
 timer.info('completed');
-// {"name":"redis","action":"completed","level":30,"time":"2016-08-15T08:50:23.566Z","duration": 1500}
+// Legacy format: {"name":"redis","action":"completed","level":30,"time":"2016-08-15T08:50:23.566Z","duration": 1500}
+// ECS format: {"event":{"action":"completed","duration":"1500"},"log":{"logger":"redis","level":30},"@timestamp":"2016-08-15T08:50:23.566Z"}
 ```
 
 ##### JsonLogger.configure(options)
@@ -182,7 +200,8 @@ const { createLogger } = require('@emartech/json-logger');
 createLogger.configure({
   formatter: JSON.stringify,
   output: console.log,
-  transformers: []
+  transformers: [],
+  outputFormat: 'ecs'
 });
 
 ```
@@ -225,7 +244,7 @@ app.use(clsAdapter.getKoaMiddleware());
 
 app.use(async () => {
   logger.info('connected');
-  // {"name":"redis","action":"connected","level":30,"time":"2016-08-15T08:50:23.566Z","request_id":"d5caaa0e-b04e-4d94-bc88-3ed3b62dc94a"}
+  // Legacy format: {"name":"redis","action":"connected","level":30,"time":"2016-08-15T08:50:23.566Z","request_id":"d5caaa0e-b04e-4d94-bc88-3ed3b62dc94a"}
 })
 ```