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"""Traces network calls using the implementation library from the settings."""
import logging
import sys
from six.moves import urllib
from azure.core.pipeline.policies import SansIOHTTPPolicy
from azure.core.settings import settings
from azure.core.tracing import SpanKind
try:
from typing import TYPE_CHECKING
except ImportError:
TYPE_CHECKING = False
if TYPE_CHECKING:
# the HttpRequest and HttpResponse related type ignores stem from this issue: #5796
from azure.core.pipeline.transport import HttpRequest, HttpResponse, AsyncHttpResponse # pylint: disable=ungrouped-imports
from azure.core.tracing._abstract_span import AbstractSpan # pylint: disable=ungrouped-imports
from azure.core.pipeline import PipelineRequest, PipelineResponse # pylint: disable=ungrouped-imports
from typing import Any, Optional, Dict, List, Union, Tuple
HttpResponseType = Union[HttpResponse, AsyncHttpResponse]
_LOGGER = logging.getLogger(__name__)
def _default_network_span_namer(http_request):
# type (HttpRequest) -> str
"""Extract the path to be used as network span name.
:param http_request: The HTTP request
:type http_request: ~azure.core.pipeline.transport.HttpRequest
:returns: The string to use as network span name
:rtype: str
"""
path = urllib.parse.urlparse(http_request.url).path
if not path:
path = "/"
return path
[docs]class DistributedTracingPolicy(SansIOHTTPPolicy):
"""The policy to create spans for Azure calls.
:keyword network_span_namer: A callable to customize the span name
:type network_span_namer: callable[[~azure.core.pipeline.transport.HttpRequest], str]
:keyword tracing_attributes: Attributes to set on all created spans
:type tracing_attributes: dict[str, str]
"""
TRACING_CONTEXT = "TRACING_CONTEXT"
_REQUEST_ID = "x-ms-client-request-id"
_RESPONSE_ID = "x-ms-request-id"
def __init__(self, **kwargs):
self._network_span_namer = kwargs.get('network_span_namer', _default_network_span_namer)
self._tracing_attributes = kwargs.get('tracing_attributes', {})
[docs] def on_request(self, request):
# type: (PipelineRequest) -> None
ctxt = request.context.options
try:
span_impl_type = settings.tracing_implementation()
if span_impl_type is None:
return
namer = ctxt.pop('network_span_namer', self._network_span_namer)
span_name = namer(request.http_request)
span = span_impl_type(name=span_name, kind=SpanKind.CLIENT)
for attr, value in self._tracing_attributes.items():
span.add_attribute(attr, value)
span.start()
headers = span.to_header()
request.http_request.headers.update(headers)
request.context[self.TRACING_CONTEXT] = span
except Exception as err: # pylint: disable=broad-except
_LOGGER.warning("Unable to start network span: %s", err)
[docs] def end_span(self, request, response=None, exc_info=None):
# type: (PipelineRequest, Optional[HttpResponseType], Optional[Tuple]) -> None
"""Ends the span that is tracing the network and updates its status."""
if self.TRACING_CONTEXT not in request.context:
return
span = request.context[self.TRACING_CONTEXT] # type: AbstractSpan
http_request = request.http_request # type: HttpRequest
if span is not None:
span.set_http_attributes(http_request, response=response)
request_id = http_request.headers.get(self._REQUEST_ID)
if request_id is not None:
span.add_attribute(self._REQUEST_ID, request_id)
if response and self._RESPONSE_ID in response.headers:
span.add_attribute(self._RESPONSE_ID, response.headers[self._RESPONSE_ID])
if exc_info:
span.__exit__(*exc_info)
else:
span.finish()
[docs] def on_response(self, request, response):
# type: (PipelineRequest, PipelineResponse) -> None
self.end_span(request, response=response.http_response)
[docs] def on_exception(self, request):
# type: (PipelineRequest) -> None
self.end_span(request, exc_info=sys.exc_info())