update docs and improve fastapi tests

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

@@ -129,10 +129,10 @@ def client_response_hook(span: Span, message: dict):
 
 The name of the added span attribute will follow the format ``http.request.header.<header_name>`` where ``<header_name>``
 is the normalized HTTP header name (lowercase, with ``-`` replaced by ``_``). The value of the attribute will be a
-single item list containing all the header values.
+list containing the header values.
 
 For example:
-``http.request.header.custom_request_header = ["<value1>,<value2>"]``
+``http.request.header.custom_request_header = ["<value1>", "<value2>"]``
 
 Response headers
 ****************
@@ -163,10 +163,10 @@ def client_response_hook(span: Span, message: dict):
 
 The name of the added span attribute will follow the format ``http.response.header.<header_name>`` where ``<header_name>``
 is the normalized HTTP header name (lowercase, with ``-`` replaced by ``_``). The value of the attribute will be a
-single item list containing all the header values.
+list containing the header values.
 
 For example:
-``http.response.header.custom_response_header = ["<value1>,<value2>"]``
+``http.response.header.custom_response_header = ["<value1>", "<value2>"]``
 
 Sanitizing headers
 ******************

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

@@ -115,7 +115,7 @@ def client_response_hook(span: Span, message: dict):
 single item list containing all the header values.
 
 For example:
-``http.request.header.custom_request_header = ["<value1>,<value2>"]``
+``http.request.header.custom_request_header = ["<value1>", "<value2>"]``
 
 Response headers
 ****************
@@ -146,10 +146,10 @@ def client_response_hook(span: Span, message: dict):
 
 The name of the added span attribute will follow the format ``http.response.header.<header_name>`` where ``<header_name>``
 is the normalized HTTP header name (lowercase, with ``-`` replaced by ``_``). The value of the attribute will be a
-single item list containing all the header values.
+list containing the header values.
 
 For example:
-``http.response.header.custom_response_header = ["<value1>,<value2>"]``
+``http.response.header.custom_response_header = ["<value1>", "<value2>"]``
 
 Sanitizing headers
 ******************

instrumentation/opentelemetry-instrumentation-fastapi/tests/test_fastapi_instrumentation.py

@@ -11,9 +11,9 @@
 # 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 unittest
 from timeit import default_timer
+from typing import Mapping, Tuple
 from unittest.mock import patch
 
 import fastapi
@@ -549,6 +549,24 @@ def test_mark_span_internal_in_presence_of_span_from_other_framework(self):
         )
 
 
+class MultiMapping(Mapping):
+
+    def __init__(self, *items: Tuple[str, str]):
+        self._items = items
+
+    def __len__(self):
+        return len(self._items)
+
+    def __getitem__(self, __key):
+        raise NotImplementedError('use .items() instead')
+
+    def __iter__(self):
+        raise NotImplementedError('use .items() instead')
+
+    def items(self):
+        return self._items
+
+
 @patch.dict(
     "os.environ",
     {
@@ -575,13 +593,15 @@ def _create_app():
 
         @app.get("/foobar")
         async def _():
-            headers = {
-                "custom-test-header-1": "test-header-value-1",
-                "custom-test-header-2": "test-header-value-2",
-                "my-custom-regex-header-1": "my-custom-regex-value-1,my-custom-regex-value-2",
-                "My-Custom-Regex-Header-2": "my-custom-regex-value-3,my-custom-regex-value-4",
-                "My-Secret-Header": "My Secret Value",
-            }
+            headers = MultiMapping(
+                ("custom-test-header-1", "test-header-value-1"),
+                ("custom-test-header-2", "test-header-value-2"),
+                ("my-custom-regex-header-1", "my-custom-regex-value-1"),
+                ("my-custom-regex-header-1", "my-custom-regex-value-2"),
+                ("My-Custom-Regex-Header-2", "my-custom-regex-value-3"),
+                ("My-Custom-Regex-Header-2", "my-custom-regex-value-4"),
+                ("My-Secret-Header", "My Secret Value"),
+            )
             content = {"message": "hello world"}
             return JSONResponse(content=content, headers=headers)
 
@@ -657,10 +677,12 @@ def test_http_custom_response_headers_in_span_attributes(self):
                 "test-header-value-2",
             ),
             "http.response.header.my_custom_regex_header_1": (
-                "my-custom-regex-value-1,my-custom-regex-value-2",
+                "my-custom-regex-value-1",
+                "my-custom-regex-value-2",
             ),
             "http.response.header.my_custom_regex_header_2": (
-                "my-custom-regex-value-3,my-custom-regex-value-4",
+                "my-custom-regex-value-3",
+                "my-custom-regex-value-4",
             ),
             "http.response.header.my_secret_header": ("[REDACTED]",),
         }

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

@@ -108,10 +108,10 @@ def client_response_hook(span: Span, message: dict):
 
 The name of the added span attribute will follow the format ``http.request.header.<header_name>`` where ``<header_name>``
 is the normalized HTTP header name (lowercase, with ``-`` replaced by ``_``). The value of the attribute will be a
-single item list containing all the header values.
+list containing the header values.
 
 For example:
-``http.request.header.custom_request_header = ["<value1>,<value2>"]``
+``http.request.header.custom_request_header = ["<value1>", "<value2>"]``
 
 Response headers
 ****************
@@ -142,10 +142,10 @@ def client_response_hook(span: Span, message: dict):
 
 The name of the added span attribute will follow the format ``http.response.header.<header_name>`` where ``<header_name>``
 is the normalized HTTP header name (lowercase, with ``-`` replaced by ``_``). The value of the attribute will be a
-single item list containing all the header values.
+list containing the header values.
 
 For example:
-``http.response.header.custom_response_header = ["<value1>,<value2>"]``
+``http.response.header.custom_response_header = ["<value1>", "<value2>"]``
 
 Sanitizing headers
 ******************