Sync vs Async API Interactive

# Sync — đơn giản, dùng cho query/read import requests response = requests.get( "https://api/dna/intent/api/v1/network-device", headers=headers ) data = response.json() # data ngay lập tức print(data["response"])

# Async + exponential backoff với jitter import random, time, requests def poll_with_backoff(task_url, headers, max_wait=300): start = time.time() delay = 2 # initial delay (seconds) while time.time() - start < max_wait: resp = requests.get(task_url, headers=headers) resp.raise_for_status() state = resp.json().get("state") if state == "COMPLETED": return resp.json() if state in ("FAILED", "ABORTED"): raise RuntimeError(f"Task failed: {resp.json()}") # Full jitter: tránh thundering herd sleep_time = min(delay * (1 + random.random()), 30) time.sleep(sleep_time) delay = min(delay * 2, 60) raise TimeoutError(f"Task không complete sau {max_wait}s")

# AWS CloudFormation — boto3 waiter (built-in polling) import boto3 cf = boto3.client("cloudformation") # Submit async task cf.create_stack( StackName="my-infra", TemplateBody=template_body ) # Waiter = polling abstraction — không cần tự viết loop waiter = cf.get_waiter("stack_create_complete") waiter.wait( StackName="my-infra", WaiterConfig={ "Delay": 15, # poll mỗi 15s "MaxAttempts": 40 # tối đa 10 phút } ) print("Stack created successfully")

# Idempotency key — tránh duplicate khi retry import uuid, requests # Generate ONCE, lưu lại trước khi submit idem_key = str(uuid.uuid4()) headers = { "Idempotency-Key": idem_key, # server dedup theo key này "Content-Type": "application/json" } # Nếu timeout và retry với CÙNG key → server trả cùng task_id # Không bị tạo duplicate deployment/VM/workflow response = requests.post(url, headers=headers, json=payload) task_id = response.json()["executionId"] # Check-before-act cho API không hỗ trợ idempotency key existing = requests.get( f"{base_url}/sites?name={site_name}", headers=headers ) if existing.json()["totalCount"] == 0: create_site(site_name)