feature: add business Metrics (#9)

* feature: add business metrics

* fix test

Co-authored-by: Ran Isenberg <ran.isenberg@cyberark.com>

Author: ran-isenberg

README.md

@@ -42,8 +42,9 @@ This repository is the complementary code examples of my blog series "AWS Lambda
 
 
 ## The Blog Series
-- First blog post - Logging:  https://isenberg-ran.medium.com/aws-lambda-cookbook-elevate-your-handlers-code-part-1-bc160a10679a
-- Second blog post- Observability: Monitoring and Tracing: https://isenberg-ran.medium.com/aws-lambda-cookbook-elevate-your-handlers-code-part-2-observability-eff158307180
+- First blog post - Logging:  https://www.ranthebuilder.cloud/post/aws-lambda-cookbook-elevate-your-handler-s-code-part-1-logging
+- Second blog post- Observability: Monitoring and Tracing: https://www.ranthebuilder.cloud/post/aws-lambda-cookbook-elevate-your-handler-s-code-part-2-observability
+- Third blog post- Observability: Business KPIs Metrics: https://isenberg-ran.medium.com/aws-lambda-cookbook-elevate-your-handlers-code-part-2-observability-eff158307180
 
 
 ## Getting started

cdk/aws_lambda_handler_cookbook/service_stack/constants.py

@@ -9,6 +9,7 @@
 API_HANDLER_LAMBDA_TIMEOUT = 10  # seconds
 POWERTOOLS_SERVICE_NAME = 'POWERTOOLS_SERVICE_NAME'
 SERVICE_NAME = 'CookBook'
+METRICS_NAMESPACE = 'my_product_kpi'
 POWERTOOLS_TRACE_DISABLED = 'POWERTOOLS_TRACE_DISABLED'
 POWER_TOOLS_LOG_LEVEL = 'LOG_LEVEL'
 BUILD_FOLDER = '.build/lambdas/'

cdk/aws_lambda_handler_cookbook/service_stack/cookbook_construct.py

@@ -16,6 +16,7 @@
     COMMION_LAYER_BUILD_FOLDER,
     GW_RESOURCE,
     LAMBDA_BASIC_EXECUTION_ROLE,
+    METRICS_NAMESPACE,
     POWER_TOOLS_LOG_LEVEL,
     POWERTOOLS_SERVICE_NAME,
     POWERTOOLS_TRACE_DISABLED,

service/handlers/my_handler.py

@@ -2,20 +2,23 @@
 from http import HTTPStatus
 from typing import Any, Dict
 
+from aws_lambda_powertools.metrics.metrics import MetricUnit
 from aws_lambda_powertools.utilities.typing import LambdaContext
 
-from service.utils.infra import logger, tracer
+from service.utils.infra import logger, metrics, tracer
 
 
 @tracer.capture_method(capture_response=False)
 def inner_function_example(event: Dict[str, Any]) -> Dict[str, Any]:
     return {}
 
 
+@metrics.log_metrics
 @tracer.capture_lambda_handler(capture_response=False)
 def my_handler(event: Dict[str, Any], context: LambdaContext) -> Dict[str, Any]:
     logger.set_correlation_id(context.aws_request_id)
     logger.debug('my_handler is called, calling inner_function_example')
     inner_function_example(event)
     logger.debug('inner_function_example finished successfully')
+    metrics.add_metric(name='ValidEvents', unit=MetricUnit.Count, value=1)
     return {'statusCode': HTTPStatus.OK, 'headers': {'Content-Type': 'application/json'}, 'body': json.dumps({'message': 'success'})}

service/utils/infra.py

@@ -1,10 +1,14 @@
 from aws_lambda_powertools.logging.logger import Logger
+from aws_lambda_powertools.metrics.metrics import Metrics
 from aws_lambda_powertools.tracing.tracer import Tracer
 
-SERVICE_NAME = 'my_service'
+METRICS_NAMESPACE = 'my_product_kpi'
 
 # JSON output format, service name can be set by environment variable "POWERTOOLS_SERVICE_NAME"
 logger: Logger = Logger()
 
 # service name can be set by environment variable "POWERTOOLS_SERVICE_NAME". Disabled by setting POWERTOOLS_TRACE_DISABLED to "True"
 tracer: Tracer = Tracer()
+
+# namespace and service name can be set by environment variable "POWERTOOLS_METRICS_NAMESPACE" and "POWERTOOLS_SERVICE_NAME" accordingly
+metrics = Metrics(namespace=METRICS_NAMESPACE)

tests/unit/test_my_handler.py

@@ -1,10 +1,20 @@
 import json
+import os
 from http import HTTPStatus
 
+import pytest
+
+from cdk.aws_lambda_handler_cookbook.service_stack.constants import POWER_TOOLS_LOG_LEVEL, POWERTOOLS_SERVICE_NAME, SERVICE_NAME
 from service.handlers.my_handler import my_handler
 from tests.utils import generate_api_gw_event, generate_context
 
 
+@pytest.fixture(scope='module', autouse=True)
+def init():
+    os.environ[POWERTOOLS_SERVICE_NAME] = SERVICE_NAME
+    os.environ[POWER_TOOLS_LOG_LEVEL] = 'DEBUG'
+
+
 def test_handler_200_ok():
     response = my_handler(generate_api_gw_event(), generate_context())
     assert response['statusCode'] == HTTPStatus.OK