Track functions attach scenario (Azure#37717)

Author: lzchen

sdk/monitor/azure-monitor-opentelemetry-exporter/CHANGELOG.md

@@ -4,6 +4,9 @@
 
 ### Features Added
 
+- Allow tracking of whether in a Azure Functions attach scenario
+    ([#37717](https://github.com/Azure/azure-sdk-for-python/pull/37717))
+
 ### Breaking Changes
 
 ### Bugs Fixed

sdk/monitor/azure-monitor-opentelemetry-exporter/azure/monitor/opentelemetry/exporter/_constants.py

@@ -10,10 +10,14 @@
 _APPLICATIONINSIGHTS_OPENTELEMETRY_RESOURCE_METRIC_DISABLED = \
     "APPLICATIONINSIGHTS_OPENTELEMETRY_RESOURCE_METRIC_DISABLED"
 _APPLICATIONINSIGHTS_METRIC_NAMESPACE_OPT_IN = "APPLICATIONINSIGHTS_METRIC_NAMESPACE_OPT_IN"
+
+# RPs
+
 _WEBSITE_SITE_NAME = "WEBSITE_SITE_NAME"
 _WEBSITE_HOME_STAMPNAME = "WEBSITE_HOME_STAMPNAME"
 _WEBSITE_HOSTNAME = "WEBSITE_HOSTNAME"
 _FUNCTIONS_WORKER_RUNTIME = "FUNCTIONS_WORKER_RUNTIME"
+_PYTHON_ENABLE_OPENTELEMETRY = "PYTHON_ENABLE_OPENTELEMETRY"
 _AKS_ARM_NAMESPACE_ID = "AKS_ARM_NAMESPACE_ID"
 
 # Network

sdk/monitor/azure-monitor-opentelemetry-exporter/azure/monitor/opentelemetry/exporter/_utils.py

@@ -23,6 +23,7 @@
 from azure.monitor.opentelemetry.exporter._constants import (
     _AKS_ARM_NAMESPACE_ID,
     _APPLICATION_INSIGHTS_RESOURCE_SCOPE,
+    _PYTHON_ENABLE_OPENTELEMETRY,
     _INSTRUMENTATIONS_BIT_MAP,
     _FUNCTIONS_WORKER_RUNTIME,
     _WEBSITE_SITE_NAME,
@@ -49,20 +50,24 @@
 def _is_on_app_service():
     return environ.get(_WEBSITE_SITE_NAME) is not None
 
+# Functions
+
 def _is_on_functions():
     return environ.get(_FUNCTIONS_WORKER_RUNTIME) is not None
 
-def _is_attach_enabled():
-    if _is_on_app_service():
-        return isdir("/agents/python/")
-    return False
-
-
 # AKS
 
 def _is_on_aks():
     return _AKS_ARM_NAMESPACE_ID in environ
 
+# Attach
+
+def _is_attach_enabled():
+    if _is_on_app_service():
+        return isdir("/agents/python/")
+    if _is_on_functions():
+        return environ.get(_PYTHON_ENABLE_OPENTELEMETRY) == "true"
+    return False
 
 def _get_sdk_version_prefix():
     sdk_version_prefix = ''