json_log_event.js

// Majority attributes are optional.
// The only required attributes are created_at, logger, level and either event + args or message.
{
  "created_at": "2016-12-31T23:59:59Z",
  "forwarded_at": "2017-01-01T00:00:00Z",
  "logger": "foo.bar.baz.module",
  "level": "INFO",
 
  // V1. Classic, unstructured log event
  "message": "OrderID '44444444-3333-2222-1111-000000000000' was not found",
 
  // V2. Structured log event
  "event": "order_not_found",
  "args": {"order_id": "44444444-3333-2222-1111-000000000000"},
 
  // Application-bound attributes
  "app": {
    "name": "ACME",
    "env": "prod"
    "build": "1.2.0.347",
    "vcs_branch": "master",
    "vcs_hash": "e69a2ab",
    "extra": {
      "arbitrary_key": "arbitrary_string_value"
    }
  }
 
  // Host-bound attributes
  "host": {
    "name": "falcon",
    "fqdn": "falcon.acme.com",
    "ip_addr": "172.16.254.1",
    "extra": {
      "arbitrary_key": "arbitrary_string_value"
    }
  }
 
  // Process-bound attributes
  "process": {
    "process_id": "1082",
    "parent_process_id": "1081",
    "process_name": "node"
    "extra": {
      "arbitrary_key": "arbitrary_string_value"
    }
  }
   
  // Attributes that bound to the execution context
  "context": {
    // Cross-cutting attributes
    "thread_id": "139939590087872",
    "thread_name": "MainThread",
    "correlation_id": "44444444-3333-2222-1111-000000000000",
 
    // App-specific and well-known attributes
    "company_id": " 44444444-3333-2222-1111-000000000000",
    "order_id": "44444444-3333-2222-1111-000000000000",
    "user_id": "44444444-3333-2222-1111-000000000000",
    
    "extra": {
      // App-specific but less-known attributes goes here
      "arbitrary_key": "arbitrary_string_value",
      "session_id": "44444444-3333-2222-1111-000000000000"
    }
  }
}