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_helpers.py
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_helpers.py
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# Copyright 2016 Google LLC All Rights Reserved.
#
# 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.
"""Helper functions for logging handlers."""
import math
import json
import re
import warnings
try:
import flask
except ImportError: # pragma: NO COVER
flask = None
from google.cloud.logging_v2.handlers.middleware.request import _get_django_request
_DJANGO_CONTENT_LENGTH = "CONTENT_LENGTH"
_DJANGO_XCLOUD_TRACE_HEADER = "HTTP_X_CLOUD_TRACE_CONTEXT"
_DJANGO_TRACEPARENT = "HTTP_TRACEPARENT"
_DJANGO_USERAGENT_HEADER = "HTTP_USER_AGENT"
_DJANGO_REMOTE_ADDR_HEADER = "REMOTE_ADDR"
_DJANGO_REFERER_HEADER = "HTTP_REFERER"
_FLASK_XCLOUD_TRACE_HEADER = "X_CLOUD_TRACE_CONTEXT"
_FLASK_TRACEPARENT = "TRACEPARENT"
_PROTOCOL_HEADER = "SERVER_PROTOCOL"
def format_stackdriver_json(record, message):
"""Helper to format a LogRecord in in Stackdriver fluentd format.
Returns:
str: JSON str to be written to the log file.
DEPRECATED: use StructuredLogHandler to write formatted logs to standard out instead.
"""
subsecond, second = math.modf(record.created)
payload = {
"message": message,
"timestamp": {"seconds": int(second), "nanos": int(subsecond * 1e9)},
"thread": record.thread,
"severity": record.levelname,
}
warnings.warn(
"format_stackdriver_json is deprecated. Use StructuredLogHandler instead.",
DeprecationWarning,
)
return json.dumps(payload, ensure_ascii=False)
def get_request_data_from_flask():
"""Get http_request and trace data from flask request headers.
Returns:
Tuple[Optional[dict], Optional[str], Optional[str], bool]:
Data related to the current http request, trace_id, span_id and trace_sampled
for the request. All fields will be None if a Flask request isn't found.
"""
if flask is None or not flask.request:
return None, None, None, False
# build http_request
http_request = {
"requestMethod": flask.request.method,
"requestUrl": flask.request.url,
"userAgent": flask.request.user_agent.string,
"protocol": flask.request.environ.get(_PROTOCOL_HEADER),
}
# find trace id and span id
# first check for w3c traceparent header
header = flask.request.headers.get(_FLASK_TRACEPARENT)
trace_id, span_id, trace_sampled = _parse_trace_parent(header)
if trace_id is None:
# traceparent not found. look for xcloud_trace_context header
header = flask.request.headers.get(_FLASK_XCLOUD_TRACE_HEADER)
trace_id, span_id, trace_sampled = _parse_xcloud_trace(header)
return http_request, trace_id, span_id, trace_sampled
def get_request_data_from_django():
"""Get http_request and trace data from django request headers.
Returns:
Tuple[Optional[dict], Optional[str], Optional[str], bool]:
Data related to the current http request, trace_id, span_id, and trace_sampled
for the request. All fields will be None if a django request isn't found.
"""
request = _get_django_request()
if request is None:
return None, None, None, False
# Django can raise django.core.exceptions.DisallowedHost here for a
# malformed HTTP_HOST header. But we don't want to import Django modules.
try:
request_url = request.build_absolute_uri()
except Exception:
request_url = None
# build http_request
http_request = {
"requestMethod": request.method,
"requestUrl": request_url,
"userAgent": request.META.get(_DJANGO_USERAGENT_HEADER),
"protocol": request.META.get(_PROTOCOL_HEADER),
}
# find trace id and span id
# first check for w3c traceparent header
header = request.META.get(_DJANGO_TRACEPARENT)
trace_id, span_id, trace_sampled = _parse_trace_parent(header)
if trace_id is None:
# traceparent not found. look for xcloud_trace_context header
header = request.META.get(_DJANGO_XCLOUD_TRACE_HEADER)
trace_id, span_id, trace_sampled = _parse_xcloud_trace(header)
return http_request, trace_id, span_id, trace_sampled
def _parse_trace_parent(header):
"""Given a w3 traceparent header, extract the trace and span ids.
For more information see https://www.w3.org/TR/trace-context/
Args:
header (str): the string extracted from the traceparent header
example: 00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01
Returns:
Tuple[Optional[dict], Optional[str], bool]:
The trace_id, span_id and trace_sampled extracted from the header
Each field will be None if header can't be parsed in expected format.
"""
trace_id = span_id = None
trace_sampled = False
# see https://www.w3.org/TR/trace-context/ for W3C traceparent format
if header:
try:
VERSION_PART = r"(?!ff)[a-f\d]{2}"
TRACE_ID_PART = r"(?![0]{32})[a-f\d]{32}"
PARENT_ID_PART = r"(?![0]{16})[a-f\d]{16}"
FLAGS_PART = r"[a-f\d]{2}"
regex = f"^\\s?({VERSION_PART})-({TRACE_ID_PART})-({PARENT_ID_PART})-({FLAGS_PART})(-.*)?\\s?$"
match = re.match(regex, header)
trace_id = match.group(2)
span_id = match.group(3)
# trace-flag component is an 8-bit bit field. Read as an int
int_flag = int(match.group(4), 16)
# trace sampled is set if the right-most bit in flag component is set
trace_sampled = bool(int_flag & 1)
except (IndexError, AttributeError):
# could not parse header as expected. Return None
pass
return trace_id, span_id, trace_sampled
def _parse_xcloud_trace(header):
"""Given an X_CLOUD_TRACE header, extract the trace and span ids.
Args:
header (str): the string extracted from the X_CLOUD_TRACE header
Returns:
Tuple[Optional[dict], Optional[str], bool]:
The trace_id, span_id and trace_sampled extracted from the header
Each field will be None if not found.
"""
trace_id = span_id = None
trace_sampled = False
# see https://cloud.google.com/trace/docs/setup for X-Cloud-Trace_Context format
if header:
try:
regex = r"([\w-]+)?(\/?([\w-]+))?(;?o=(\d))?"
match = re.match(regex, header)
trace_id = match.group(1)
span_id = match.group(3)
trace_sampled = match.group(5) == "1"
except IndexError:
pass
return trace_id, span_id, trace_sampled
def get_request_data():
"""Helper to get http_request and trace data from supported web
frameworks (currently supported: Flask and Django).
Returns:
Tuple[Optional[dict], Optional[str], Optional[str], bool]:
Data related to the current http request, trace_id, span_id, and trace_sampled
for the request. All fields will be None if a http request isn't found.
"""
checkers = (
get_request_data_from_django,
get_request_data_from_flask,
)
for checker in checkers:
http_request, trace_id, span_id, trace_sampled = checker()
if http_request is not None:
return http_request, trace_id, span_id, trace_sampled
return None, None, None, False