improv: update example to reflect middleware feat

Author: heitorlessa

python/aws_lambda_powertools/middleware_factory/factory.py

@@ -76,12 +76,16 @@ def lambda_handler(event, context):
 
     **Trace execution of custom middleware**
 
+        from aws_lambda_powertools.tracing import Tracer
         from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
 
+        tracer = Tracer(service="payment") # or via env var
+        ...
         @lambda_handler_decorator(trace_execution=True)
         def log_response(handler, event, context):
             ...
 
+        @tracer.capture_lambda_handler
         @log_response
         def lambda_handler(event, context):
             return True
@@ -119,7 +123,7 @@ def wrapper(event, context):
                 middleware = functools.partial(decorator, func, event, context, **kwargs)
                 if trace_execution:
                     tracer = Tracer(auto_patch=False)
-                    tracer.create_subsegment(name=f"## middleware {decorator.__qualname__}")
+                    tracer.create_subsegment(name=f"## {decorator.__qualname__}")
                     response = middleware()
                     tracer.end_subsegment()
                 else:

python/example/hello_world/app.py

@@ -1,9 +1,11 @@
 import json
 
+import requests
+
 from aws_lambda_powertools.logging import logger_inject_lambda_context, logger_setup
-from aws_lambda_powertools.tracing import Tracer
 from aws_lambda_powertools.metrics import Metrics, MetricUnit, single_metric
-import requests
+from aws_lambda_powertools.middleware_factory import lambda_handler_decorator
+from aws_lambda_powertools.tracing import Tracer
 
 tracer = Tracer()
 logger = logger_setup()
@@ -13,8 +15,22 @@
 
 metrics.add_dimension(name="operation", value="example")
 
+
+@lambda_handler_decorator(trace_execution=True)
+def my_middleware(handler, event, context, say_hello=False):
+    if say_hello:
+        print("========= HELLO PARAM DETECTED =========")
+    print("========= Logging event before Handler is called =========")
+    print(event)
+    ret = handler(event, context)
+    print("========= Logging response after Handler is called =========")
+    print(ret)
+    return ret
+
+
 @metrics.log_metrics
 @tracer.capture_lambda_handler
+@my_middleware(say_hello=True)
 @logger_inject_lambda_context
 def lambda_handler(event, context):
     """Sample pure Lambda function
@@ -41,25 +57,22 @@ def lambda_handler(event, context):
     if _cold_start:
         logger.debug("Recording cold start metric")
         metrics.add_metric(name="ColdStart", unit=MetricUnit.Count, value=1)
-        metrics.add_dimension(name="function_name", value=context.function_name)            
+        metrics.add_dimension(name="function_name", value=context.function_name)
         _cold_start = False
 
     try:
         ip = requests.get("http://checkip.amazonaws.com/")
         metrics.add_metric(name="SuccessfulLocations", unit="Count", value=1)
     except requests.RequestException as e:
         # Send some context about this error to Lambda Logs
-        logger.error(e)
-        raise e
-    
+        logger.exception(e, exc_info=True)
+        raise
+
     with single_metric(name="UniqueMetricDimension", unit="Seconds", value=1) as metric:
         metric.add_dimension(name="unique_dimension", value="for_unique_metric")
 
     logger.info("Returning message to the caller")
     return {
         "statusCode": 200,
-        "body": json.dumps({
-            "message": "hello world",
-            "location": ip.text.replace("\n", "")
-        }),
+        "body": json.dumps({"message": "hello world", "location": ip.text.replace("\n", "")}),
     }