From c8900cfbb03a898f4249f0e0dacf9886a232dd3a Mon Sep 17 00:00:00 2001
From: "(Eliseo) Nathaniel Ruiz Nowell" <nathanielruiz98@gmail.com>
Date: Wed, 4 Aug 2021 13:49:19 -0700
Subject: [PATCH] Aggregator calls Resource.create() to set default attributes

---
 CHANGELOG.md                                  |  4 +-
 .../opentelemetry/sdk/resources/__init__.py   | 56 +++++++------------
 2 files changed, 22 insertions(+), 38 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4c3f32686c5..985c3eed373 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,8 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased](https://github.com/open-telemetry/opentelemetry-python/compare/v1.4.0-0.23b0...HEAD)
-- `opentelemetry-sdk` `get_aggregated_resource()` returns default resource and service name
-  whenever called
+- `opentelemetry-sdk` `get_aggregated_resource()` sets default resource and service name
+  attributes whenever called
   ([#2013])(https://github.com/open-telemetry/opentelemetry-python/pull/2013)
 - `opentelemetry-distro` & `opentelemetry-sdk` Moved Auto Instrumentation Configurator code to SDK
   to let distros use its default implementation
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/resources/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/resources/__init__.py
index d329be5aa06..39210fdf3e2 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/resources/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/resources/__init__.py
@@ -165,10 +165,20 @@ def create(
         """
         if not attributes:
             attributes = {}
-
-        return get_aggregated_resources(
-            [], final_resource=Resource(attributes, schema_url)
-        )
+        resource = _DEFAULT_RESOURCE.merge(
+            OTELResourceDetector().detect()
+        ).merge(Resource(attributes, schema_url))
+        if not resource.attributes.get(SERVICE_NAME, None):
+            default_service_name = "unknown_service"
+            process_executable_name = resource.attributes.get(
+                PROCESS_EXECUTABLE_NAME, None
+            )
+            if process_executable_name:
+                default_service_name += ":" + process_executable_name
+            resource = resource.merge(
+                Resource({SERVICE_NAME: default_service_name}, schema_url)
+            )
+        return resource
 
     @staticmethod
     def get_empty() -> "Resource":
@@ -272,7 +282,6 @@ def detect(self) -> "Resource":
 def get_aggregated_resources(
     detectors: typing.List["ResourceDetector"],
     initial_resource: typing.Optional[Resource] = None,
-    final_resource: typing.Optional[Resource] = None,
     timeout=5,
 ) -> "Resource":
     """Retrieves resources from detectors in the order that they were passed
@@ -282,19 +291,14 @@ def get_aggregated_resources(
     :param timeout: Number of seconds to wait for each detector to return
     :return:
     """
-    detectors_resource = (
-        _DEFAULT_RESOURCE.merge(initial_resource)
-        if initial_resource
-        else _DEFAULT_RESOURCE
-    )
-    detectors = [OTELResourceDetector()] + detectors
+    detectors_merged_resource = initial_resource or _EMPTY_RESOURCE
 
     with concurrent.futures.ThreadPoolExecutor(max_workers=4) as executor:
         futures = [executor.submit(detector.detect) for detector in detectors]
         for detector_ind, future in enumerate(futures):
             detector = detectors[detector_ind]
             try:
-                detected_resources = future.result(timeout=timeout)
+                detected_resource = future.result(timeout=timeout)
             # pylint: disable=broad-except
             except Exception as ex:
                 if detector.raise_on_error:
@@ -302,30 +306,10 @@ def get_aggregated_resources(
                 logger.warning(
                     "Exception %s in detector %s, ignoring", ex, detector
                 )
-                detected_resources = _EMPTY_RESOURCE
+                detected_resource = _EMPTY_RESOURCE
             finally:
-                detectors_resource = detectors_resource.merge(
-                    detected_resources
+                detectors_merged_resource = detectors_merged_resource.merge(
+                    detected_resource
                 )
 
-    merged_resource = (
-        detectors_resource.merge(final_resource)
-        if final_resource
-        else detectors_resource
-    )
-
-    if merged_resource.attributes.get(SERVICE_NAME):
-        return merged_resource
-
-    default_service_name = "unknown_service"
-
-    process_executable_name = merged_resource.attributes.get(
-        PROCESS_EXECUTABLE_NAME
-    )
-
-    if process_executable_name:
-        default_service_name += ":" + process_executable_name
-
-    return merged_resource.merge(
-        Resource({SERVICE_NAME: default_service_name})
-    )
+    return Resource.create().merge(detectors_merged_resource)