As of January 1, 2020 this library no longer supports Python 2 on the latest released version.
Library versions released prior to that date will continue to be available. For more information please
visit Python 2 support on Google Cloud.
Source code for google.cloud.logging_v2.handlers.handlers
# Copyright 2016 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Python :mod:`logging` handlers for Cloud Logging."""
import collections
import json
import logging
from typing import Optional, IO, Type
from google.cloud.logging_v2.handlers.transports import (
BackgroundThreadTransport,
Transport,
)
from google.cloud.logging_v2.handlers._monitored_resources import (
detect_resource,
add_resource_labels,
)
from google.cloud.logging_v2.handlers._helpers import get_request_data
from google.cloud.logging_v2.resource import Resource
DEFAULT_LOGGER_NAME = "python"
"""Defaults for filtering out noisy loggers"""
EXCLUDED_LOGGER_DEFAULTS = (
"google.api_core.bidi",
"werkzeug",
)
"""Exclude internal logs from propagating through handlers"""
_INTERNAL_LOGGERS = (
"google.cloud",
"google.auth",
"google_auth_httplib2",
)
"""These environments require us to remove extra handlers on setup"""
_CLEAR_HANDLER_RESOURCE_TYPES = ("gae_app", "cloud_function")
[docs]class CloudLoggingFilter(logging.Filter):
"""Python standard ``logging`` Filter class to add Cloud Logging
information to each LogRecord.
When attached to a LogHandler, each incoming log will be modified
to include new Cloud Logging relevant data. This data can be manually
overwritten using the `extras` argument when writing logs.
"""
def __init__(self, project=None, default_labels=None):
self.project = project
self.default_labels = default_labels if default_labels else {}
@staticmethod
def _infer_source_location(record):
"""Helper function to infer source location data from a LogRecord.
Will default to record.source_location if already set
"""
if hasattr(record, "source_location"):
return record.source_location
else:
name_map = [
("line", "lineno"),
("file", "pathname"),
("function", "funcName"),
]
output = {}
for gcp_name, std_lib_name in name_map:
value = getattr(record, std_lib_name, None)
if value is not None:
output[gcp_name] = value
return output if output else None
[docs] def filter(self, record):
"""
Add new Cloud Logging data to each LogRecord as it comes in
"""
user_labels = getattr(record, "labels", {})
# infer request data from the environment
(
inferred_http,
inferred_trace,
inferred_span,
inferred_sampled,
) = get_request_data()
if inferred_trace is not None and self.project is not None:
# add full path for detected trace
inferred_trace = f"projects/{self.project}/traces/{inferred_trace}"
# set new record values
record._resource = getattr(record, "resource", None)
record._trace = getattr(record, "trace", inferred_trace) or None
record._span_id = getattr(record, "span_id", inferred_span) or None
record._trace_sampled = bool(getattr(record, "trace_sampled", inferred_sampled))
record._http_request = getattr(record, "http_request", inferred_http)
record._source_location = CloudLoggingFilter._infer_source_location(record)
# add logger name as a label if possible
logger_label = {"python_logger": record.name} if record.name else {}
record._labels = {**logger_label, **self.default_labels, **user_labels} or None
# create string representations for structured logging
record._trace_str = record._trace or ""
record._span_id_str = record._span_id or ""
record._trace_sampled_str = "true" if record._trace_sampled else "false"
record._http_request_str = json.dumps(
record._http_request or {}, ensure_ascii=False
)
record._source_location_str = json.dumps(
record._source_location or {}, ensure_ascii=False
)
record._labels_str = json.dumps(record._labels or {}, ensure_ascii=False)
return True
[docs]class CloudLoggingHandler(logging.StreamHandler):
"""Handler that directly makes Cloud Logging API calls.
This is a Python standard ``logging`` handler using that can be used to
route Python standard logging messages directly to the Stackdriver
Logging API.
This handler is used when not in GAE or GKE environment.
This handler supports both an asynchronous and synchronous transport.
Example:
.. code-block:: python
import logging
import google.cloud.logging
from google.cloud.logging_v2.handlers import CloudLoggingHandler
client = google.cloud.logging.Client()
handler = CloudLoggingHandler(client)
cloud_logger = logging.getLogger('cloudLogger')
cloud_logger.setLevel(logging.INFO)
cloud_logger.addHandler(handler)
cloud_logger.error('bad news') # API call
"""
def __init__(
self,
client,
*,
name: str = DEFAULT_LOGGER_NAME,
transport: Type[Transport] = BackgroundThreadTransport,
resource: Resource = None,
labels: Optional[dict] = None,
stream: Optional[IO] = None,
**kwargs,
):
"""
Args:
client (~logging_v2.client.Client):
The authenticated Google Cloud Logging client for this
handler to use.
name (str): the name of the custom log in Cloud Logging.
Defaults to 'python'. The name of the Python logger will be represented
in the ``python_logger`` field.
transport (~logging_v2.transports.Transport):
Class for creating new transport objects. It should
extend from the base :class:`.Transport` type and
implement :meth`.Transport.send`. Defaults to
:class:`.BackgroundThreadTransport`. The other
option is :class:`.SyncTransport`.
resource (~logging_v2.resource.Resource):
Resource for this Handler. If not given, will be inferred from the environment.
labels (Optional[dict]): Additional labels to attach to logs.
stream (Optional[IO]): Stream to be used by the handler.
"""
super(CloudLoggingHandler, self).__init__(stream)
if not resource:
# infer the correct monitored resource from the local environment
resource = detect_resource(client.project)
self.name = name
self.client = client
self.transport = transport(client, name, resource=resource)
self.project_id = client.project
self.resource = resource
self.labels = labels
# add extra keys to log record
log_filter = CloudLoggingFilter(project=self.project_id, default_labels=labels)
self.addFilter(log_filter)
[docs] def emit(self, record):
"""Actually log the specified logging record.
Overrides the default emit behavior of ``StreamHandler``.
See https://docs.python.org/2/library/logging.html#handler-objects
Args:
record (logging.LogRecord): The record to be logged.
"""
resource = record._resource or self.resource
labels = record._labels
message = _format_and_parse_message(record, self)
labels = {**add_resource_labels(resource, record), **(labels or {})} or None
# send off request
self.transport.send(
record,
message,
resource=resource,
labels=labels,
trace=record._trace,
span_id=record._span_id,
trace_sampled=record._trace_sampled,
http_request=record._http_request,
source_location=record._source_location,
)
def _format_and_parse_message(record, formatter_handler):
"""
Helper function to apply formatting to a LogRecord message,
and attempt to parse encoded JSON into a dictionary object.
Resulting output will be of type (str | dict | None)
Args:
record (logging.LogRecord): The record object representing the log
formatter_handler (logging.Handler): The handler used to format the log
"""
passed_json_fields = getattr(record, "json_fields", {})
# if message is a dictionary, use dictionary directly
if isinstance(record.msg, collections.abc.Mapping):
payload = record.msg
# attach any extra json fields if present
if passed_json_fields and isinstance(
passed_json_fields, collections.abc.Mapping
):
payload = {**payload, **passed_json_fields}
return payload
# format message string based on superclass
message = formatter_handler.format(record)
try:
# attempt to parse encoded json into dictionary
if message[0] == "{":
json_message = json.loads(message)
if isinstance(json_message, collections.abc.Mapping):
message = json_message
except (json.decoder.JSONDecodeError, IndexError):
# log string is not valid json
pass
# if json_fields was set, create a dictionary using that
if passed_json_fields and isinstance(passed_json_fields, collections.abc.Mapping):
passed_json_fields = passed_json_fields.copy()
if message != "None":
passed_json_fields["message"] = message
return passed_json_fields
# if formatted message contains no content, return None
return message if message != "None" else None
[docs]def setup_logging(
handler, *, excluded_loggers=EXCLUDED_LOGGER_DEFAULTS, log_level=logging.INFO
):
"""Attach a logging handler to the Python root logger
Excludes loggers that this library itself uses to avoid
infinite recursion.
Example:
.. code-block:: python
import logging
import google.cloud.logging
from google.cloud.logging_v2.handlers import CloudLoggingHandler
client = google.cloud.logging.Client()
handler = CloudLoggingHandler(client)
google.cloud.logging.handlers.setup_logging(handler)
logging.getLogger().setLevel(logging.DEBUG)
logging.error('bad news') # API call
Args:
handler (logging.handler): the handler to attach to the global handler
excluded_loggers (Optional[Tuple[str]]): The loggers to not attach the handler
to. This will always include the loggers in the
path of the logging client itself.
log_level (Optional[int]): Python logging log level. Defaults to
:const:`logging.INFO`.
"""
all_excluded_loggers = set(excluded_loggers + _INTERNAL_LOGGERS)
logger = logging.getLogger()
# remove built-in handlers on App Engine or Cloud Functions environments
if detect_resource().type in _CLEAR_HANDLER_RESOURCE_TYPES:
logger.handlers.clear()
logger.setLevel(log_level)
logger.addHandler(handler)
for logger_name in all_excluded_loggers:
# prevent excluded loggers from propagating logs to handler
logger = logging.getLogger(logger_name)
logger.propagate = False
