Fix exception in Urllib3 when dealing with filelike body.

Author: isra17

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Fix exception in Urllib3 when dealing with filelike body.
+  ([#1399](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1399))
+
 ### Added
 
 - Add connection attributes to sqlalchemy connect span

instrumentation/opentelemetry-instrumentation-urllib3/src/opentelemetry/instrumentation/urllib3/__init__.py

@@ -64,7 +64,9 @@ def response_hook(span, request, response):
 ---
 """
 
+import collections.abc
 import contextlib
+import io
 import typing
 from timeit import default_timer
 from typing import Collection
@@ -213,18 +215,20 @@ def instrumented_urlopen(wrapped, instance, args, kwargs):
             if callable(response_hook):
                 response_hook(span, instance, response)
 
-            request_size = 0 if body is None else len(body)
+            request_size = _get_body_size(body)
             response_size = int(response.headers.get("Content-Length", 0))
+
             metric_attributes = _create_metric_attributes(
                 instance, response, method
             )
 
             duration_histogram.record(
                 elapsed_time, attributes=metric_attributes
             )
-            request_size_histogram.record(
-                request_size, attributes=metric_attributes
-            )
+            if request_size is not None:
+                request_size_histogram.record(
+                    request_size, attributes=metric_attributes
+                )
             response_size_histogram.record(
                 response_size, attributes=metric_attributes
             )
@@ -268,6 +272,16 @@ def _get_url(
     return url
 
 
+def _get_body_size(body: object) -> typing.Optional[int]:
+    if body is None:
+        return 0
+    if isinstance(body, collections.abc.Sized):
+        return len(body)
+    if isinstance(body, io.BytesIO):
+        return body.getbuffer().nbytes
+    return None
+
+
 def _should_append_port(scheme: str, port: typing.Optional[int]) -> bool:
     if not port:
         return False