03 - Metrics

app-metrics.py

import json
import time

from aws_lambda_powertools import Logger, Metrics, Tracer
from aws_lambda_powertools.logging import correlation_paths
from aws_lambda_powertools.metrics import MetricUnit

logger = Logger()
tracer = Tracer()
metrics = Metrics()


@tracer.capture_method
def create_payment(payment):
    order_key = payment["order_key"]
    logger.info(f"Order key: %s", order_key)

    # Simulate failure
    if "FAILURE" in order_key:
        tracer.put_annotation("PAYMENT_STATUS", "ERROR")
        metrics.add_metric(name="PaymentFailure", unit=MetricUnit.Count, value=1)
        raise RuntimeError("Failed to make payment")

    # Simulate a slow transaction
    time.sleep(2)
    tracer.put_annotation(key="ORDER_KEY", value=order_key)
    tracer.put_annotation(key="PAYMENT_STATUS", value="SUCCESS")
    metrics.add_metric(name="PaymentSuccessful", unit=MetricUnit.Count, value=1)

    return {"order_id": "1111111", "status": "SUCCESS"}


@metrics.log_metrics(capture_cold_start_metric=True)
@tracer.capture_lambda_handler
@logger.inject_lambda_context(log_event=True, correlation_id_path=correlation_paths.API_GATEWAY_REST)
def lambda_handler(event, context):
    payment = create_payment(json.loads(event["body"]))
    return {
        "statusCode": 200,
        "headers": {"Content-Type": "application/json"},
        "body": json.dumps(payment),
    }