Ensure @timestamp, log.level, and message fields are ordered per spec

Author: sethmlarson

ecs_logging/_utils.py

@@ -103,4 +103,42 @@ def merge_dicts(from_, into):
 
 def json_dumps(value):
     # type: (Dict[str, Any]) -> str
-    return json.dumps(value, sort_keys=True, separators=(",", ":"))
+
+    # Ensure that the first three fields are '@timestamp',
+    # 'log.level', and 'message' per ECS spec
+    ordered_fields = []
+    try:
+        ordered_fields.append(("@timestamp", value.pop("@timestamp")))
+    except KeyError:
+        pass
+
+    # log.level can either be nested or not nested so we have to try both
+    try:
+        ordered_fields.append(("log.level", value["log"].pop("level")))
+        if not value["log"]:  # Remove the 'log' dictionary if it's now empty
+            value.pop("log", None)
+    except KeyError:
+        try:
+            ordered_fields.append(("log.level", value.pop("log.level")))
+        except KeyError:
+            pass
+    try:
+        ordered_fields.append(("message", value.pop("message")))
+    except KeyError:
+        pass
+
+    # Because we want to use 'sorted_keys=True' we manually build
+    # the first three keys and then build the rest with json.dumps()
+    if ordered_fields:
+        ordered_json = ",".join('"%s":"%s"' % kv for kv in ordered_fields)
+        if value:
+            return "{%s,%s" % (
+                ordered_json,
+                json.dumps(value, sort_keys=True, separators=(",", ":"))[1:],
+            )
+        else:
+            return "{%s}" % ordered_json
+    # If there are no fields with ordering requirements we
+    # pass everything into json.dumps()
+    else:
+        return json.dumps(value, sort_keys=True, separators=(",", ":"))

tests/test_apm.py

@@ -34,7 +34,7 @@ def test_elasticapm_structlog_log_correlation_ecs_fields():
     ecs.pop("@timestamp")
     assert ecs == {
         "ecs": {"version": "1.6.0"},
-        "log": {"level": "info"},
+        "log.level": "info",
         "message": "test message",
         "span": {"id": span_id},
         "trace": {"id": trace_id},
@@ -72,8 +72,8 @@ def test_elastic_apm_stdlib_no_filter_log_correlation_ecs_fields():
     ecs = json.loads(stream.getvalue().rstrip())
     assert ecs == {
         "ecs": {"version": "1.6.0"},
+        "log.level": "info",
         "log": {
-            "level": "info",
             "logger": "apm-logger",
             "origin": {
                 "file": {"name": "test_apm.py"},
@@ -116,8 +116,8 @@ def test_elastic_apm_stdlib_with_filter_log_correlation_ecs_fields():
     ecs = json.loads(stream.getvalue().rstrip())
     assert ecs == {
         "ecs": {"version": "1.6.0"},
+        "log.level": "info",
         "log": {
-            "level": "info",
             "logger": "apm-logger",
             "origin": {
                 "file": {"name": "test_apm.py"},
@@ -163,8 +163,8 @@ def test_elastic_apm_stdlib_exclude_fields():
     ecs = json.loads(stream.getvalue().rstrip())
     assert ecs == {
         "ecs": {"version": "1.6.0"},
+        "log.level": "info",
         "log": {
-            "level": "info",
             "logger": "apm-logger",
             "origin": {
                 "file": {"name": "test_apm.py"},

tests/test_stdlib_formatter.py

@@ -39,9 +39,9 @@ def test_record_formatted():
     formatter = ecs_logging.StdlibFormatter(exclude_fields=["process"])
 
     assert formatter.format(make_record()) == (
-        '{"@timestamp":"2020-03-20T14:12:46.123Z","ecs":{"version":"1.6.0"},'
-        '"log":{"level":"debug","logger":"logger-name","origin":{"file":{"line":10,"name":"file.py"},'
-        '"function":"test_function"},"original":"1: hello"},"message":"1: hello"}'
+        '{"@timestamp":"2020-03-20T14:12:46.123Z","log.level":"debug","message":"1: hello","ecs":{"version":"1.6.0"},'
+        '"log":{"logger":"logger-name","origin":{"file":{"line":10,"name":"file.py"},"function":"test_function"},'
+        '"original":"1: hello"}}'
     )
 
 
@@ -54,9 +54,9 @@ def format_to_ecs(self, record):
 
     formatter = CustomFormatter(exclude_fields=["process"])
     assert formatter.format(make_record()) == (
-        '{"@timestamp":"2020-03-20T14:12:46.123Z","custom":"field","ecs":{"version":"1.6.0"},'
-        '"log":{"level":"debug","logger":"logger-name","origin":{"file":{"line":10,"name":"file.py"},'
-        '"function":"test_function"},"original":"1: hello"},"message":"1: hello"}'
+        '{"@timestamp":"2020-03-20T14:12:46.123Z","log.level":"debug","message":"1: hello",'
+        '"custom":"field","ecs":{"version":"1.6.0"},"log":{"logger":"logger-name","origin":'
+        '{"file":{"line":10,"name":"file.py"},"function":"test_function"},"original":"1: hello"}}'
     )
 
 
@@ -68,9 +68,9 @@ def test_can_be_set_on_handler():
     handler.handle(make_record())
 
     assert stream.getvalue() == (
-        '{"@timestamp":"2020-03-20T14:12:46.123Z","ecs":{"version":"1.6.0"},'
-        '"log":{"level":"debug","logger":"logger-name","origin":{"file":{"line":10,"name":"file.py"},'
-        '"function":"test_function"},"original":"1: hello"},"message":"1: hello"}\n'
+        '{"@timestamp":"2020-03-20T14:12:46.123Z","log.level":"debug","message":"1: hello",'
+        '"ecs":{"version":"1.6.0"},"log":{"logger":"logger-name","origin":{"file":{"line":10,'
+        '"name":"file.py"},"function":"test_function"},"original":"1: hello"}}\n'
     )
 
 
@@ -103,8 +103,8 @@ def test_extra_is_merged(time, logger):
     assert ecs == {
         "@timestamp": "2020-03-20T16:16:37.187Z",
         "ecs": {"version": "1.6.0"},
+        "log.level": "info",
         "log": {
-            "level": "info",
             "logger": logger.name,
             "origin": {
                 "file": {"name": "test_stdlib_formatter.py"},
@@ -161,7 +161,7 @@ def test_stack_trace_limit_disabled(stack_trace_limit, logger):
 
     ecs = json.loads(stream.getvalue().rstrip())
     assert ecs["error"] == {"message": "error!", "type": "ValueError"}
-    assert ecs["log"]["level"] == "info"
+    assert ecs["log.level"] == "info"
     assert ecs["message"] == "there was an error"
     assert ecs["log"]["original"] == "there was an error"
 
@@ -195,7 +195,7 @@ def h():
         "message": "error!",
         "type": "ValueError",
     }
-    assert ecs["log"]["level"] == "info"
+    assert ecs["log.level"] == "info"
     assert ecs["message"] == "there was an error"
     assert ecs["log"]["original"] == "there was an error"
 

tests/test_structlog_formatter.py

@@ -14,8 +14,9 @@ def test_event_dict_formatted(time):
 
     formatter = ecs_logging.StructlogFormatter()
     assert formatter(None, "debug", make_event_dict()) == (
-        '{"@timestamp":"2020-03-20T16:16:37.187Z","ecs":{"version":"1.6.0"},'
-        '"log":{"level":"debug","logger":"logger-name"},"message":"test message"}'
+        '{"@timestamp":"2020-03-20T16:16:37.187Z","log.level":"debug",'
+        '"message":"test message","ecs":{"version":"1.6.0"},'
+        '"log":{"logger":"logger-name"}}'
     )
 
 
@@ -35,7 +36,7 @@ def test_can_be_set_as_processor(time):
     logger.debug("test message", custom="key", **{"dot.ted": 1})
 
     assert stream.getvalue() == (
-        '{"@timestamp":"2020-03-20T16:16:37.187Z","custom":"key",'
-        '"dot":{"ted":1},"ecs":{"version":"1.6.0"},"log":{"level":"debug"},'
-        '"message":"test message"}\n'
+        '{"@timestamp":"2020-03-20T16:16:37.187Z","log.level":"debug",'
+        '"message":"test message","custom":"key","dot":{"ted":1},'
+        '"ecs":{"version":"1.6.0"}}\n'
     )

tests/test_utils.py

@@ -1,5 +1,5 @@
 import pytest
-from ecs_logging._utils import flatten_dict, de_dot, normalize_dict
+from ecs_logging._utils import flatten_dict, de_dot, normalize_dict, json_dumps
 
 
 def test_flatten_dict():
@@ -30,3 +30,43 @@ def test_normalize_dict():
 
 def test_normalize_dict_with_array():
     assert normalize_dict({"a": ["1", "2"]}) == {"a": ["1", "2"]}
+
+
+@pytest.mark.parametrize(
+    ["value", "expected"],
+    [
+        ({}, "{}"),
+        ({"log": {"level": "info"}}, '{"log.level":"info"}'),
+        ({"log.level": "info"}, '{"log.level":"info"}'),
+        (
+            {"log": {"level": "info", "message": "hello"}},
+            '{"log.level":"info","log":{"message":"hello"}}',
+        ),
+        ({"@timestamp": "2021-01-01..."}, '{"@timestamp":"2021-01-01..."}'),
+        ({"message": "hello"}, '{"message":"hello"}'),
+        ({"custom": "value"}, '{"custom":"value"}'),
+        ({"log.level": "info"}, '{"log.level":"info"}'),
+        (
+            {"log": {"message": "hello"}, "message": "hello"},
+            '{"message":"hello","log":{"message":"hello"}}',
+        ),
+        (
+            {
+                "log": {"message": "hello", "level": "info"},
+                "message": "hello",
+                "@timestamp": "2021-01-01...",
+            },
+            '{"@timestamp":"2021-01-01...","log.level":"info","message":"hello","log":{"message":"hello"}}',
+        ),
+        (
+            {
+                "log": {"level": "info"},
+                "message": "hello",
+                "@timestamp": "2021-01-01...",
+            },
+            '{"@timestamp":"2021-01-01...","log.level":"info","message":"hello"}',
+        ),
+    ],
+)
+def test_json_dumps(value, expected):
+    assert json_dumps(value) == expected