Add log.* fields to spec (#34)

Author: felixbarny

spec/README.md

@@ -44,7 +44,7 @@ The following example describes a richer set of fields in an event that has not
         "origin": {
             "file": {
                 "name": "App.java",
-                "line": 42,
+                "line": 42
             },
             "function": "methodName"
         }

spec/spec.json

@@ -81,6 +81,29 @@
             "type": "string",
             "required": false,
             "url": "https://www.elastic.co/guide/en/ecs/current/ecs-process.html"
+        },
+        "log.logger": {
+            "type": "string",
+            "required": false,
+            "url": "https://www.elastic.co/guide/en/ecs/current/ecs-log.html"
+        },
+        "log.origin.file.line": {
+            "type": "integer",
+            "required": false,
+            "url": "https://www.elastic.co/guide/en/ecs/current/ecs-log.html",
+            "comment": "Should be opt-in as it requires the logging library to capture a stack trace for each log event."
+        },
+        "log.origin.file.name": {
+            "type": "string",
+            "required": false,
+            "url": "https://www.elastic.co/guide/en/ecs/current/ecs-log.html",
+            "comment": "Should be opt-in as it requires the logging library to capture a stack trace for each log event."
+        },
+        "log.origin.function": {
+            "type": "string",
+            "required": false,
+            "url": "https://www.elastic.co/guide/en/ecs/current/ecs-log.html",
+            "comment": "Should be opt-in as it requires the logging library to capture a stack trace for each log event."
         }
     }
 }