docs: recommend to use named loggers instead of the root logger as described in #34787 (#35771)

Author: johschmidt42

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

@@ -154,6 +154,14 @@ The following sections provide several code snippets covering some of the most c
 
 Review the [OpenTelemetry Logging SDK][ot_logging_sdk] to learn how to use OpenTelemetry components to collect logs.
 
+When integrating the `AzureMonitorLogExporter`, it's **strongly advised to utilize a named logger** rather
+than the root logger.
+This recommendation stems from the exporter's dependency on `azure-core` for constructing and dispatching requests.
+Since `azure-core` itself uses a Python logger, attaching the handler to the root logger would
+inadvertently capture and export these internal log messages as well.
+This triggers a recursive loop of logging and exporting, leading to an unnecessary proliferation of log data.
+To avoid this, configure a named logger for your application's logging needs or set up your logging handler to filter out logs originating from the SDK library.
+
 #### Export Hello World Log
 
 ```python
@@ -181,13 +189,12 @@ exporter = AzureMonitorLogExporter(
 )
 
 logger_provider.add_log_record_processor(BatchLogRecordProcessor(exporter))
-handler = LoggingHandler()
-
-# Attach LoggingHandler to root logger
-logging.getLogger().addHandler(handler)
-logging.getLogger().setLevel(logging.NOTSET)
 
+# Attach LoggingHandler to namespaced logger
+handler = LoggingHandler()
 logger = logging.getLogger(__name__)
+logger.addHandler(handler)
+logger.setLevel(logging.NOTSET)
 
 logger.warning("Hello World!")
 
@@ -226,13 +233,12 @@ exporter = AzureMonitorLogExporter(
 )
 
 logger_provider.add_log_record_processor(BatchLogRecordProcessor(exporter))
-handler = LoggingHandler()
-
-# Attach LoggingHandler to root logger
-logging.getLogger().addHandler(handler)
-logging.getLogger().setLevel(logging.NOTSET)
 
+# Attach LoggingHandler to namespaced logger
+handler = LoggingHandler()
 logger = logging.getLogger(__name__)
+logger.addHandler(handler)
+logger.setLevel(logging.NOTSET)
 
 logger.info("INFO: Outside of span")
 with tracer.start_as_current_span("foo"):
@@ -266,13 +272,12 @@ exporter = AzureMonitorLogExporter(
 )
 
 logger_provider.add_log_record_processor(BatchLogRecordProcessor(exporter))
-handler = LoggingHandler()
-
-# Attach LoggingHandler to root logger
-logging.getLogger().addHandler(handler)
-logging.getLogger().setLevel(logging.NOTSET)
 
+# Attach LoggingHandler to namespaced logger
+handler = LoggingHandler()
 logger = logging.getLogger(__name__)
+logger.addHandler(handler)
+logger.setLevel(logging.NOTSET)
 
 # Custom properties
 logger.debug("DEBUG: Debug with properties", extra={"debug": "true"})