Add exclude lists for flask integration

ext/opentelemetry-ext-flask/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- Add exclude list for paths and hosts
+  ([#6300](https://github.com/open-telemetry/opentelemetry-python/pull/630))
+
 ## 0.6b0
 
 Released 2020-03-30

ext/opentelemetry-ext-flask/README.rst

@@ -16,6 +16,16 @@ Installation
 
     pip install opentelemetry-ext-flask
 
+Configuration
+-------------
+
+Exclude lists
+*************
+Excludes certain hosts and paths from being tracked. Pass in comma delimited string into environment variables.
+
+Excluded hosts: OPENTELEMETRY_PYTHON_FLASK_EXCLUDED_HOSTS
+Excluded paths: OPENTELEMETRY_PYTHON_FLASK_EXCLUDED_PATHS
+
 
 References
 ----------

ext/opentelemetry-ext-flask/src/opentelemetry/ext/flask/__init__.py

@@ -51,10 +51,14 @@ def hello():
 import flask
 
 import opentelemetry.ext.wsgi as otel_wsgi
-from opentelemetry import context, propagators, trace
+from opentelemetry import configuration, context, propagators, trace
 from opentelemetry.auto_instrumentation.instrumentor import BaseInstrumentor
 from opentelemetry.ext.flask.version import __version__
-from opentelemetry.util import time_ns
+from opentelemetry.util import (
+    disable_tracing_hostname,
+    disable_tracing_path,
+    time_ns,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -80,17 +84,18 @@ def wrapped_app(environ, start_response):
             environ[_ENVIRON_STARTTIME_KEY] = time_ns()
 
             def _start_response(status, response_headers, *args, **kwargs):
-                span = flask.request.environ.get(_ENVIRON_SPAN_KEY)
-                if span:
-                    otel_wsgi.add_response_attributes(
-                        span, status, response_headers
-                    )
-                else:
-                    logger.warning(
-                        "Flask environ's OpenTelemetry span "
-                        "missing at _start_response(%s)",
-                        status,
-                    )
+                if not _disable_trace(flask.request.url):
+                    span = flask.request.environ.get(_ENVIRON_SPAN_KEY)
+                    if span:
+                        otel_wsgi.add_response_attributes(
+                            span, status, response_headers
+                        )
+                    else:
+                        logger.warning(
+                            "Flask environ's OpenTelemetry span "
+                            "missing at _start_response(%s)",
+                            status,
+                        )
 
                 return start_response(
                     status, response_headers, *args, **kwargs
@@ -102,6 +107,9 @@ def _start_response(status, response_headers, *args, **kwargs):
 
         @self.before_request
         def _before_flask_request():
+            # Do not trace if the url is excluded
+            if _disable_trace(flask.request.url):
+                return
             environ = flask.request.environ
             span_name = (
                 flask.request.endpoint
@@ -132,6 +140,9 @@ def _before_flask_request():
 
         @self.teardown_request
         def _teardown_flask_request(exc):
+            # Not traced if the url is excluded
+            if _disable_trace(flask.request.url):
+                return
             activation = flask.request.environ.get(_ENVIRON_ACTIVATION_KEY)
             if not activation:
                 logger.warning(
@@ -150,6 +161,20 @@ def _teardown_flask_request(exc):
             context.detach(flask.request.environ.get(_ENVIRON_TOKEN))
 
 
+def _disable_trace(url):
+    excluded_hosts = configuration.Configuration().FLASK_EXCLUDED_HOSTS
+    excluded_paths = configuration.Configuration().FLASK_EXCLUDED_PATHS
+    if excluded_hosts:
+        excluded_hosts = str.split(excluded_hosts, ",")
+        if disable_tracing_hostname(url, excluded_hosts):
+            return True
+    if excluded_paths:
+        excluded_paths = str.split(excluded_paths, ",")
+        if disable_tracing_path(url, excluded_paths):
+            return True
+    return False
+
+
 class FlaskInstrumentor(BaseInstrumentor):
     """A instrumentor for flask.Flask
 

ext/opentelemetry-ext-flask/tests/test_flask_integration.py

@@ -13,12 +13,14 @@
 # limitations under the License.
 
 import unittest
+from unittest.mock import patch
 
 from flask import Flask, request
 from werkzeug.test import Client
 from werkzeug.wrappers import BaseResponse
 
 from opentelemetry import trace as trace_api
+from opentelemetry.configuration import Configuration
 from opentelemetry.test.wsgitestutil import WsgiTestBase
 
 
@@ -45,18 +47,31 @@ def setUp(self):
         # No instrumentation code is here because it is present in the
         # conftest.py file next to this file.
         super().setUp()
-
+        Configuration._instance = None  # pylint:disable=protected-access
+        Configuration.__slots__ = []
         self.app = Flask(__name__)
 
         def hello_endpoint(helloid):
             if helloid == 500:
                 raise ValueError(":-(")
             return "Hello: " + str(helloid)
 
+        def excluded_endpoint():
+            return "excluded"
+
+        def excluded2_endpoint():
+            return "excluded2"
+
         self.app.route("/hello/<int:helloid>")(hello_endpoint)
+        self.app.route("/excluded")(excluded_endpoint)
+        self.app.route("/excluded2")(excluded2_endpoint)
 
         self.client = Client(self.app, BaseResponse)
 
+    def tearDown(self):
+        Configuration._instance = None  # pylint:disable=protected-access
+        Configuration.__slots__ = []
+
     def test_only_strings_in_environ(self):
         """
         Some WSGI servers (such as Gunicorn) expect keys in the environ object
@@ -80,9 +95,8 @@ def test_simple(self):
         expected_attrs = expected_attributes(
             {"http.target": "/hello/123", "http.route": "/hello/<int:helloid>"}
         )
-        resp = self.client.get("/hello/123")
-        self.assertEqual(200, resp.status_code)
-        self.assertEqual([b"Hello: 123"], list(resp.response))
+        self.client.get("/hello/123")
+
         span_list = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(span_list), 1)
         self.assertEqual(span_list[0].name, "hello_endpoint")
@@ -126,6 +140,21 @@ def test_internal_error(self):
         self.assertEqual(span_list[0].kind, trace_api.SpanKind.SERVER)
         self.assertEqual(span_list[0].attributes, expected_attrs)
 
+    @patch.dict(
+        "os.environ",  # type: ignore
+        {
+            "OPENTELEMETRY_PYTHON_FLASK_EXCLUDED_HOSTS": "http://localhost/excluded",
+            "OPENTELEMETRY_PYTHON_FLASK_EXCLUDED_PATHS": "excluded2",
+        },
+    )
+    def test_excluded_path(self):
+        self.client.get("/hello/123")
+        self.client.get("/excluded")
+        self.client.get("/excluded2")
+        span_list = self.memory_exporter.get_finished_spans()
+        self.assertEqual(len(span_list), 1)
+        self.assertEqual(span_list[0].name, "hello_endpoint")
+
 
 if __name__ == "__main__":
     unittest.main()

opentelemetry-api/src/opentelemetry/util/__init__.py

@@ -11,9 +11,10 @@
 # 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.
+import re
 import time
 from logging import getLogger
-from typing import Union
+from typing import Sequence, Union
 
 from pkg_resources import iter_entry_points
 
@@ -33,18 +34,44 @@ def time_ns() -> int:
         return int(time.time() * 1e9)
 
 
-def _load_provider(provider: str) -> Union["TracerProvider", "MeterProvider"]:  # type: ignore
+def _load_provider(
+    provider: str,
+) -> Union["TracerProvider", "MeterProvider"]:  # type: ignore
     try:
         return next(  # type: ignore
             iter_entry_points(
                 "opentelemetry_{}".format(provider),
-                name=getattr(  # type: ignore
-                    Configuration(), provider, "default_{}".format(provider),  # type: ignore
+                name=getattr(
+                    Configuration(),  # type: ignore
+                    provider,
+                    "default_{}".format(provider),
                 ),
             )
         ).load()()
     except Exception:  # pylint: disable=broad-except
-        logger.error(
-            "Failed to load configured provider %s", provider,
-        )
+        logger.error("Failed to load configured provider %s", provider)
         raise
+
+
+# Pattern for matching the 'https://', 'http://', 'ftp://' part.
+URL_PATTERN = "^(https?|ftp):\\/\\/"
+
+
+def disable_tracing_path(url: str, excluded_paths: Sequence[str]) -> bool:
+    # Remove the 'https?|ftp://' if exists
+    url = re.sub(URL_PATTERN, "", url)
+
+    # Split the url by the first '/' and get the path part
+    url_path = url.split("/", 1)[1]
+
+    for path in excluded_paths:
+        if url_path.startswith(path):
+            return True
+
+    return False
+
+
+def disable_tracing_hostname(
+    url: str, excluded_hostnames: Sequence[str]
+) -> bool:
+    return url in excluded_hostnames