converted textmap propagator getter to a class and added keys method

exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/propagator.py

@@ -39,24 +39,24 @@ class DatadogFormat(TextMapPropagator):
 
     def extract(
         self,
-        get_from_carrier: Getter[TextMapPropagatorT],
+        get_from_carrier: Getter,
         carrier: TextMapPropagatorT,
         context: typing.Optional[Context] = None,
     ) -> Context:
         trace_id = extract_first_element(
-            get_from_carrier(carrier, self.TRACE_ID_KEY)
+            get_from_carrier.get(carrier, self.TRACE_ID_KEY)
         )
 
         span_id = extract_first_element(
-            get_from_carrier(carrier, self.PARENT_ID_KEY)
+            get_from_carrier.get(carrier, self.PARENT_ID_KEY)
         )
 
         sampled = extract_first_element(
-            get_from_carrier(carrier, self.SAMPLING_PRIORITY_KEY)
+            get_from_carrier.get(carrier, self.SAMPLING_PRIORITY_KEY)
         )
 
         origin = extract_first_element(
-            get_from_carrier(carrier, self.ORIGIN_KEY)
+            get_from_carrier.get(carrier, self.ORIGIN_KEY)
         )
 
         trace_flags = trace.TraceFlags()

exporter/opentelemetry-exporter-datadog/tests/test_datadog_format.py

@@ -22,9 +22,18 @@
 FORMAT = propagator.DatadogFormat()
 
 
-def get_as_list(dict_object, key):
-    value = dict_object.get(key)
-    return [value] if value is not None else []
+class Getter:
+    @staticmethod
+    def get(dict_object, key):
+        value = dict_object.get(key)
+        return [value] if value is not None else []
+
+    @staticmethod
+    def keys(dict_object):
+        return dict_object.keys()
+
+
+get_as_list = Getter()
 
 
 class TestDatadogFormat(unittest.TestCase):

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

@@ -32,18 +32,32 @@
 from opentelemetry.trace.status import Status, StatusCanonicalCode
 
 
-def get_header_from_scope(scope: dict, header_name: str) -> typing.List[str]:
-    """Retrieve a HTTP header value from the ASGI scope.
+class Getter:
+    @staticmethod
+    def get(scope: dict, header_name: str) -> typing.List[str]:
+        """Retrieve a HTTP header value from the ASGI scope.
 
-    Returns:
-        A list with a single string with the header value if it exists, else an empty list.
-    """
-    headers = scope.get("headers")
-    return [
-        value.decode("utf8")
-        for (key, value) in headers
-        if key.decode("utf8") == header_name
-    ]
+        Returns:
+            A list with a single string with the header value if it exists, else an empty list.
+        """
+        headers = scope.get("headers")
+        return [
+            value.decode("utf8")
+            for (key, value) in headers
+            if key.decode("utf8") == header_name
+        ]
+
+    @staticmethod
+    def keys(scope: dict) -> typing.List[str]:
+        """Retrieve all the  HTTP header keys for an ASGI scope..
+
+        Returns:
+            A list with all the keys in scope.
+        """
+        return scope.keys()
+
+
+get_header_from_scope = Getter()
 
 
 def collect_request_attributes(scope):
@@ -72,10 +86,10 @@ def collect_request_attributes(scope):
     http_method = scope.get("method")
     if http_method:
         result["http.method"] = http_method
-    http_host_value = ",".join(get_header_from_scope(scope, "host"))
+    http_host_value = ",".join(get_header_from_scope.get(scope, "host"))
     if http_host_value:
         result["http.server_name"] = http_host_value
-    http_user_agent = get_header_from_scope(scope, "user-agent")
+    http_user_agent = get_header_from_scope.get(scope, "user-agent")
     if len(http_user_agent) > 0:
         result["http.user_agent"] = http_user_agent[0]
 

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

@@ -118,6 +118,7 @@ def _trace_prerun(self, *args, **kwargs):
             return
 
         request = task.request
+        carrier_extractor = Getter()
         tracectx = propagators.extract(carrier_extractor, request) or {}
         parent = get_current_span(tracectx)
 
@@ -248,8 +249,14 @@ def _trace_retry(*args, **kwargs):
         span.set_attribute(_TASK_RETRY_REASON_KEY, str(reason))
 
 
-def carrier_extractor(carrier, key):
-    value = getattr(carrier, key, [])
-    if isinstance(value, str) or not isinstance(value, Iterable):
-        value = (value,)
-    return value
+class Getter:
+    @staticmethod
+    def get(carrier, key):
+        value = getattr(carrier, key, [])
+        if isinstance(value, str) or not isinstance(value, Iterable):
+            value = (value,)
+        return value
+
+    @staticmethod
+    def keys(carrier):
+        return carrier.keys()

instrumentation/opentelemetry-instrumentation-grpc/src/opentelemetry/instrumentation/grpc/_server.py

@@ -110,6 +110,18 @@ def _check_error_code(span, servicer_context, rpc_info):
         rpc_info.error = servicer_context.code
 
 
+class Getter:
+    @staticmethod
+    def get(metadata, key) -> List[str]:
+        md_dict = {md.key: md.value for md in metadata}
+        return [md_dict[key]] if key in md_dict else []
+
+    @staticmethod
+    def keys(metadata) -> List[str]:
+        md_dict = {md.key: md.value for md in metadata}
+        return md_dict.keys()
+
+
 class OpenTelemetryServerInterceptor(
     grpcext.UnaryServerInterceptor, grpcext.StreamServerInterceptor
 ):
@@ -121,11 +133,8 @@ def __init__(self, tracer):
     def _set_remote_context(self, servicer_context):
         metadata = servicer_context.invocation_metadata()
         if metadata:
-            md_dict = {md.key: md.value for md in metadata}
-
-            def get_from_grpc_metadata(metadata, key) -> List[str]:
-                return [md_dict[key]] if key in md_dict else []
 
+            get_from_grpc_metadata = Getter()
             # Update the context with the traceparent from the RPC metadata.
             ctx = propagators.extract(get_from_grpc_metadata, metadata)
             token = attach(ctx)

instrumentation/opentelemetry-instrumentation-opentracing-shim/src/opentelemetry/instrumentation/opentracing_shim/__init__.py

@@ -503,6 +503,47 @@ def tracer(self) -> "TracerShim":
         return self._tracer
 
 
+class Getter:
+    """This class provides an interface that enables extracting propagated
+    fields from a carrier
+
+    """
+
+    @staticmethod
+    def get(carrier, key):
+        """Function that can retrieve zero
+        or more values from the carrier. In the case that
+        the value does not exist, returns an empty list.
+
+        Args:
+            carrier: and object which contains values that are
+                used to construct a Context. This object
+                must be paired with an appropriate get_from_carrier
+                which understands how to extract a value from it.
+            key: key of a field in carrier.
+        Returns:
+            first value of the propagation key or an empty list if the key doesn't exist.
+        """
+
+        value = carrier.get(key)
+        return [value] if value is not None else []
+
+    @staticmethod
+    def keys(carrier):
+        """Function that can retrieve all the keys in a carrier object.
+
+        Args:
+            carrier: and object which contains values that are
+                used to construct a Context. This object
+                must be paired with an appropriate get_from_carrier
+                which understands how to extract a value from it.
+        Returns:
+            list of keys from the carrier.
+        """
+
+        return carrier.keys()
+
+
 class TracerShim(Tracer):
     """Wraps a :class:`opentelemetry.trace.Tracer` object.
 
@@ -706,10 +747,7 @@ def extract(self, format: object, carrier: object):
         if format not in self._supported_formats:
             raise UnsupportedFormatException
 
-        def get_as_list(dict_object, key):
-            value = dict_object.get(key)
-            return [value] if value is not None else []
-
+        get_as_list = Getter()
         propagator = propagators.get_global_textmap()
         ctx = propagator.extract(get_as_list, carrier)
         span = get_current_span(ctx)

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

@@ -174,11 +174,15 @@ def _log_exception(tracer, func, handler, args, kwargs):
     return func(*args, **kwargs)
 
 
-def _get_header_from_request_headers(
-    headers: dict, header_name: str
-) -> typing.List[str]:
-    header = headers.get(header_name)
-    return [header] if header else []
+class Getter:
+    @staticmethod
+    def get(headers: dict, header_name: str) -> typing.List[str]:
+        header = headers.get(header_name)
+        return [header] if header else []
+
+    @staticmethod
+    def keys(headers) -> typing.List[str]:
+        return headers.keys()
 
 
 def _get_attributes_from_request(request):
@@ -206,6 +210,7 @@ def _get_operation_name(handler, request):
 
 
 def _start_span(tracer, handler, start_time) -> _TraceContext:
+    _get_header_from_request_headers = Getter()
     token = context.attach(
         propagators.extract(
             _get_header_from_request_headers, handler.request.headers,

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

@@ -66,19 +66,31 @@ def hello():
 _HTTP_VERSION_PREFIX = "HTTP/"
 
 
-def get_header_from_environ(
-    environ: dict, header_name: str
-) -> typing.List[str]:
-    """Retrieve a HTTP header value from the PEP3333-conforming WSGI environ.
+class Getter:
+    @staticmethod
+    def get(environ: dict, header_name: str) -> typing.List[str]:
+        """Retrieve a HTTP header value from the PEP3333-conforming WSGI environ.
 
-    Returns:
-        A list with a single string with the header value if it exists, else an empty list.
-    """
-    environ_key = "HTTP_" + header_name.upper().replace("-", "_")
-    value = environ.get(environ_key)
-    if value is not None:
-        return [value]
-    return []
+        Returns:
+            A list with a single string with the header value if it exists, else an empty list.
+        """
+        environ_key = "HTTP_" + header_name.upper().replace("-", "_")
+        value = environ.get(environ_key)
+        if value is not None:
+            return [value]
+        return []
+
+    @staticmethod
+    def keys(environ: dict) -> typing.List[str]:
+        """Retrieve all the  HTTP header keys for an PEP3333-conforming WSGI environ.
+
+        Returns:
+            A list with all the keys in environ.
+        """
+        return environ.keys()
+
+
+get_header_from_environ = Getter()
 
 
 def setifnotnone(dic, key, value):

opentelemetry-api/src/opentelemetry/baggage/propagation/__init__.py

@@ -29,7 +29,7 @@ class BaggagePropagator(textmap.TextMapPropagator):
 
     def extract(
         self,
-        get_from_carrier: textmap.Getter[textmap.TextMapPropagatorT],
+        get_from_carrier: textmap.Getter,
         carrier: textmap.TextMapPropagatorT,
         context: typing.Optional[Context] = None,
     ) -> Context:
@@ -43,7 +43,7 @@ def extract(
             context = get_current()
 
         header = _extract_first_element(
-            get_from_carrier(carrier, self._BAGGAGE_HEADER_NAME)
+            get_from_carrier.get(carrier, self._BAGGAGE_HEADER_NAME)
         )
 
         if not header or len(header) > self.MAX_HEADER_LENGTH:

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

@@ -82,16 +82,16 @@ def example_route():
 
 
 def extract(
-    get_from_carrier: textmap.Getter[textmap.TextMapPropagatorT],
+    get_from_carrier: textmap.Getter,
     carrier: textmap.TextMapPropagatorT,
     context: typing.Optional[Context] = None,
 ) -> Context:
     """ Uses the configured propagator to extract a Context from the carrier.
 
     Args:
-        get_from_carrier: a function that can retrieve zero
-            or more values from the carrier. In the case that
-            the value does not exist, return an empty list.
+        get_from_carrier: an object which contains a get function that can retrieve zero
+            or more values from the carrier and a keys function that can get all the keys
+            from carrier.
         carrier: and object which contains values that are
             used to construct a Context. This object
             must be paired with an appropriate get_from_carrier

opentelemetry-api/src/opentelemetry/propagators/composite.py

@@ -35,7 +35,7 @@ def __init__(
 
     def extract(
         self,
-        get_from_carrier: textmap.Getter[textmap.TextMapPropagatorT],
+        get_from_carrier: textmap.Getter,
         carrier: textmap.TextMapPropagatorT,
         context: typing.Optional[Context] = None,
     ) -> Context: