Added ability to extract span attributes from Tonado request objects.

OTEL_PYTHON_TONADO_TRACED_REQUEST_ATTRS env var can be set to a command
separated list of attributes names that will be extracted from Tornado's
request object and set as attributes on spans.

Author: owais

Diff for: instrumentation/opentelemetry-instrumentation-django/src/opentelemetry/instrumentation/django/middleware.py

@@ -17,6 +17,7 @@
 from opentelemetry.configuration import Configuration
 from opentelemetry.context import attach, detach
 from opentelemetry.instrumentation.django.version import __version__
+from opentelemetry.instrumentation.utils import extract_attributes_from_object
 from opentelemetry.instrumentation.wsgi import (
     add_response_attributes,
     collect_request_attributes,
@@ -102,10 +103,9 @@ def process_request(self, request):
         tracer = get_tracer(__name__, __version__)
 
         attributes = collect_request_attributes(environ)
-        for attr in self._traced_request_attrs:
-            value = getattr(request, attr, None)
-            if value is not None:
-                attributes[attr] = str(value)
+        attributes = extract_attributes_from_object(
+            request, self._traced_request_attrs, attributes
+        )
 
         span = tracer.start_span(
             self._get_span_name(request),

Diff for: instrumentation/opentelemetry-instrumentation-tornado/README.rst

@@ -31,6 +31,18 @@ A comma separated list of paths that should not be automatically traced. For exa
 
 Then any requests made to ``/healthz`` and ``/ping`` will not be automatically traced.
 
+Request attributes
+********************
+To extract certain attributes from Tornado's request object and use them as span attributes, set the environment variable ``OTEL_PYTHON_TORNADO_TRACED_REQUEST_ATTRS`` to a comma
+delimited list of request attribute names. 
+
+For example,
+
+::
+
+    export OTEL_PYTHON_TONADO_TRACED_REQUEST_ATTRS='uri,query'
+
+will extract path_info and content_type attributes from every traced request and add them as span attritbues.
 
 References
 ----------

Diff for: instrumentation/opentelemetry-instrumentation-tornado/src/opentelemetry/instrumentation/tornado/__init__.py

@@ -50,6 +50,7 @@ def get(self):
 from opentelemetry.instrumentation.instrumentor import BaseInstrumentor
 from opentelemetry.instrumentation.tornado.version import __version__
 from opentelemetry.instrumentation.utils import (
+    extract_attributes_from_object,
     http_status_to_canonical_code,
     unwrap,
 )
@@ -79,6 +80,7 @@ def get_traced_request_attrs():
         attrs = []
     return attrs
 
+
 _excluded_urls = get_excluded_urls()
 _traced_attrs = get_traced_request_attrs()
 
@@ -205,7 +207,7 @@ def _get_attributes_from_request(request):
     if request.remote_ip:
         attrs["net.peer.ip"] = request.remote_ip
 
-    return attrs
+    return extract_attributes_from_object(request, _traced_attrs, attrs)
 
 
 def _get_operation_name(handler, request):
@@ -220,6 +222,7 @@ def _start_span(tracer, handler, start_time) -> _TraceContext:
             _get_header_from_request_headers, handler.request.headers,
         )
     )
+
     span = tracer.start_span(
         _get_operation_name(handler, handler.request),
         kind=trace.SpanKind.SERVER,

Diff for: instrumentation/opentelemetry-instrumentation-tornado/tests/test_instrumentation.py

@@ -339,6 +339,21 @@ def test_excluded(path):
         test_excluded("/healthz")
         test_excluded("/ping")
 
+    @patch(
+        "opentelemetry.instrumentation.tornado._traced_attrs",
+        ["uri", "full_url", "query"],
+    )
+    def test_traced_attrs(self):
+        self.fetch("/ping?q=abc&b=123")
+        spans = self.sorted_spans(self.memory_exporter.get_finished_spans())
+        self.assertEqual(len(spans), 2)
+        server = spans[0]
+        self.assertEqual(server.kind, SpanKind.SERVER)
+        self.assert_span_has_attributes(
+            server, {"uri": "/ping?q=abc&b=123", "query": "q=abc&b=123",}
+        )
+        self.memory_exporter.clear()
+
 
 class TestTornadoUninstrument(TornadoTest):
     def test_uninstrument(self):

Diff for: opentelemetry-instrumentation/src/opentelemetry/instrumentation/utils.py

@@ -12,11 +12,26 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from typing import Dict, Sequence
+
 from wrapt import ObjectProxy
 
 from opentelemetry.trace.status import StatusCanonicalCode
 
 
+def extract_attributes_from_object(
+    obj: any, attributes: Sequence[str], existing: Dict[str, str] = None
+) -> Dict[str, str]:
+    extracted = {}
+    if existing:
+        extracted.update(existing)
+    for attr in attributes:
+        value = getattr(obj, attr, None)
+        if value is not None:
+            extracted[attr] = str(value)
+    return extracted
+
+
 def http_status_to_canonical_code(
     status: int, allow_redirect: bool = True
 ) -> StatusCanonicalCode: