feat: allow custom labels with standard library logging (#264)

google/cloud/logging_v2/client.py

@@ -362,9 +362,9 @@ def get_default_handler(self, **kw):
             ):
                 # Cloud Functions with runtimes > 3.8 supports structured logs on standard out
                 # 3.7 should use the standard CloudLoggingHandler, which sends logs over the network.
-                return StructuredLogHandler(**kw, project=self.project)
+                return StructuredLogHandler(**kw, project_id=self.project)
             elif monitored_resource.type == _RUN_RESOURCE_TYPE:
-                return StructuredLogHandler(**kw, project=self.project)
+                return StructuredLogHandler(**kw, project_id=self.project)
         return CloudLoggingHandler(self, resource=monitored_resource, **kw)
 
     def setup_logging(

google/cloud/logging_v2/handlers/handlers.py

@@ -37,8 +37,9 @@ class CloudLoggingFilter(logging.Filter):
     the `extras` argument when writing logs.
     """
 
-    def __init__(self, project=None):
+    def __init__(self, project=None, default_labels=None):
         self.project = project
+        self.default_labels = default_labels if default_labels else {}
 
     def filter(self, record):
         # ensure record has all required fields set
@@ -61,6 +62,12 @@ def filter(self, record):
         inferred_http, inferred_trace = get_request_data()
         if inferred_trace is not None and self.project is not None:
             inferred_trace = f"projects/{self.project}/traces/{inferred_trace}"
+        # set labels
+        user_labels = getattr(record, "labels", {})
+        record.total_labels = {**self.default_labels, **user_labels}
+        record.total_labels_str = ", ".join(
+            [f'"{k}": "{v}"' for k, v in record.total_labels.items()]
+        )
 
         record.trace = getattr(record, "trace", inferred_trace) or ""
         record.http_request = getattr(record, "http_request", inferred_http) or {}
@@ -126,8 +133,7 @@ def __init__(
                 option is :class:`.SyncTransport`.
             resource (~logging_v2.resource.Resource):
                 Resource for this Handler. Defaults to ``global``.
-            labels (Optional[dict]): Monitored resource of the entry, defaults
-                to the global resource type.
+            labels (Optional[dict]): Additional labels to attach to logs.
             stream (Optional[IO]): Stream to be used by the handler.
         """
         super(CloudLoggingHandler, self).__init__(stream)
@@ -138,7 +144,8 @@ def __init__(
         self.resource = resource
         self.labels = labels
         # add extra keys to log record
-        self.addFilter(CloudLoggingFilter(self.project_id))
+        log_filter = CloudLoggingFilter(project=self.project_id, default_labels=labels)
+        self.addFilter(log_filter)
 
     def emit(self, record):
         """Actually log the specified logging record.
@@ -151,22 +158,16 @@ def emit(self, record):
             record (logging.LogRecord): The record to be logged.
         """
         message = super(CloudLoggingHandler, self).format(record)
-        user_labels = getattr(record, "labels", {})
-        # merge labels
-        total_labels = self.labels if self.labels is not None else {}
-        total_labels.update(user_labels)
-        if len(total_labels) == 0:
-            total_labels = None
         # send off request
         self.transport.send(
             record,
             message,
             resource=getattr(record, "resource", self.resource),
-            labels=total_labels,
-            trace=getattr(record, "trace", None),
-            span_id=getattr(record, "span_id", None),
-            http_request=getattr(record, "http_request", None),
-            source_location=getattr(record, "source_location", None),
+            labels=getattr(record, "total_labels", None) or None,
+            trace=getattr(record, "trace", None) or None,
+            span_id=getattr(record, "span_id", None) or None,
+            http_request=getattr(record, "http_request", None) or None,
+            source_location=getattr(record, "source_location", None) or None,
         )
 
 

google/cloud/logging_v2/handlers/structured_log.py

@@ -19,26 +19,34 @@
 
 from google.cloud.logging_v2.handlers.handlers import CloudLoggingFilter
 
-GCP_FORMAT = '{"message": "%(message)s", "severity": "%(levelname)s", "logging.googleapis.com/trace": "%(trace)s", "logging.googleapis.com/sourceLocation": { "file": "%(file)s", "line": "%(line)d", "function": "%(function)s"}, "httpRequest": {"requestMethod": "%(request_method)s", "requestUrl": "%(request_url)s", "userAgent": "%(user_agent)s", "protocol": "%(protocol)s"} }'
+GCP_FORMAT = (
+    '{"message": "%(message)s", '
+    '"severity": "%(levelname)s", '
+    '"logging.googleapis.com/labels": { %(total_labels_str)s }, '
+    '"logging.googleapis.com/trace": "%(trace)s", '
+    '"logging.googleapis.com/sourceLocation": { "file": "%(file)s", "line": "%(line)d", "function": "%(function)s"}, '
+    '"httpRequest": {"requestMethod": "%(request_method)s", "requestUrl": "%(request_url)s", "userAgent": "%(user_agent)s", "protocol": "%(protocol)s"} }'
+)
 
 
 class StructuredLogHandler(logging.StreamHandler):
     """Handler to format logs into the Cloud Logging structured log format,
     and write them to standard output
     """
 
-    def __init__(self, *, name=None, stream=None, project=None):
+    def __init__(self, *, labels=None, stream=None, project_id=None):
         """
         Args:
-            name (Optional[str]): The name of the custom log in Cloud Logging.
+            labels (Optional[dict]): Additional labels to attach to logs.
             stream (Optional[IO]): Stream to be used by the handler.
+            project (Optional[str]): Project Id associated with the logs.
         """
         super(StructuredLogHandler, self).__init__(stream=stream)
-        self.name = name
-        self.project_id = project
+        self.project_id = project_id
 
         # add extra keys to log record
-        self.addFilter(CloudLoggingFilter(project))
+        log_filter = CloudLoggingFilter(project=project_id, default_labels=labels)
+        self.addFilter(log_filter)
 
         # make logs appear in GCP structured logging format
         self.formatter = logging.Formatter(GCP_FORMAT)

tests/unit/handlers/test_handlers.py

@@ -268,22 +268,27 @@ def test_emit(self):
         )
         logname = "loggername"
         message = "hello world"
-        labels = {"test-key": "test-value"}
         record = logging.LogRecord(logname, logging, None, None, message, None, None)
-        record.labels = labels
-        handler.emit(record)
+        handler.handle(record)
         self.assertEqual(
             handler.transport.send_called_with,
-            (record, message, _GLOBAL_RESOURCE, labels, None, None, None, None),
+            (record, message, _GLOBAL_RESOURCE, None, None, None, None, None),
         )
 
     def test_emit_manual_field_override(self):
         from google.cloud.logging_v2.logger import _GLOBAL_RESOURCE
         from google.cloud.logging_v2.resource import Resource
 
         client = _Client(self.PROJECT)
+        default_labels = {
+            "default_key": "default-value",
+            "overwritten_key": "bad_value",
+        }
         handler = self._make_one(
-            client, transport=_Transport, resource=_GLOBAL_RESOURCE
+            client,
+            transport=_Transport,
+            resource=_GLOBAL_RESOURCE,
+            labels=default_labels,
         )
         logname = "loggername"
         message = "hello world"
@@ -299,9 +304,14 @@ def test_emit_manual_field_override(self):
         setattr(record, "source_location", expected_source)
         expected_resource = Resource(type="test", labels={})
         setattr(record, "resource", expected_resource)
-        expected_labels = {"test-label": "manual"}
-        setattr(record, "labels", expected_labels)
-        handler.emit(record)
+        added_labels = {"added_key": "added_value", "overwritten_key": "new_value"}
+        expected_labels = {
+            "default_key": "default-value",
+            "overwritten_key": "new_value",
+            "added_key": "added_value",
+        }
+        setattr(record, "labels", added_labels)
+        handler.handle(record)
 
         self.assertEqual(
             handler.transport.send_called_with,

tests/unit/handlers/test_structured_log.py

@@ -40,17 +40,18 @@ def index():
 
     def test_ctor_defaults(self):
         handler = self._make_one()
-        self.assertIsNone(handler.name)
+        self.assertIsNone(handler.project_id)
 
-    def test_ctor_w_name(self):
-        handler = self._make_one(name="foo")
-        self.assertEqual(handler.name, "foo")
+    def test_ctor_w_project(self):
+        handler = self._make_one(project_id="foo")
+        self.assertEqual(handler.project_id, "foo")
 
     def test_format(self):
         import logging
         import json
 
-        handler = self._make_one()
+        labels = {"default_key": "default-value"}
+        handler = self._make_one(labels=labels)
         logname = "loggername"
         message = "hello world，嗨 世界"
         pathname = "testpath"
@@ -74,6 +75,7 @@ def test_format(self):
                 "userAgent": "",
                 "protocol": "",
             },
+            "logging.googleapis.com/labels": labels,
         }
         handler.filter(record)
         result = json.loads(handler.format(record))
@@ -106,6 +108,7 @@ def test_format_minimal(self):
                 "userAgent": "",
                 "protocol": "",
             },
+            "logging.googleapis.com/labels": {},
         }
         handler.filter(record)
         result = json.loads(handler.format(record))
@@ -160,7 +163,11 @@ def test_format_overrides(self):
         import logging
         import json
 
-        handler = self._make_one()
+        default_labels = {
+            "default_key": "default-value",
+            "overwritten_key": "bad_value",
+        }
+        handler = self._make_one(labels=default_labels)
         logname = "loggername"
         message = "hello world，嗨 世界"
         record = logging.LogRecord(logname, logging.INFO, "", 0, message, None, None)
@@ -172,6 +179,8 @@ def test_format_overrides(self):
         record.http_request = {"requestUrl": overwrite_path}
         record.source_location = {"file": overwrite_file}
         record.trace = overwrite_trace
+        added_labels = {"added_key": "added_value", "overwritten_key": "new_value"}
+        record.labels = added_labels
         expected_payload = {
             "logging.googleapis.com/trace": overwrite_trace,
             "logging.googleapis.com/sourceLocation": {
@@ -185,6 +194,11 @@ def test_format_overrides(self):
                 "userAgent": "",
                 "protocol": "",
             },
+            "logging.googleapis.com/labels": {
+                "default_key": "default-value",
+                "overwritten_key": "new_value",
+                "added_key": "added_value",
+            },
         }
 
         app = self.create_app()