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Microservices patterns

Service boundaries, discovery, inter-service calls, and decomposition patterns.

6 matches

How to Handle mTLS Certificate Rotation in Python

Detect mTLS certificate file changes by tracking modification time and hot-reload the SSL context in a running service.

import ssl
import tempfile
import datetime
from pathlib import Path


class MTLSContext:
    def __init__(self, cert_path, key_path, ca_path):
        self.cert_path = Path(cert_path)
        self.key_path = Path(key_path)
        self.ca_path = Path(ca_path)
        self.context = None
        self.last_loaded_mtime …

13 0 Open

Microservices patterns easy

How to Implement an Exactly-Once Deduplication Store in Python

Implement a Python class that deduplicates keys exactly once, tracking first-seen timestamps and duplicate counts.

deduplication exactly-once set

Python

from datetime import datetime
from typing import Any, Hashable


class ExactlyOnceStore:
    def __init__(self) -> None:
        self._seen: set[Hashable] = set()
        self._first_seen: dict[Hashable, datetime] = {}
        self._counts: dict[Hashable, int] = {}

    def add(self, key: Hashable, value: Any = None) …

13 0 Open

Microservices patterns medium

How to Mock Service Call Timeouts in Python

Simulate service calls with configurable timeouts using Mock to patch sleep and randomness, covering success and timeout cases.

microservices testing timeout

Python

import time
from unittest.mock import Mock, patch

# Simulate a service call with configurable timeout
def call_service(service_name, timeout=5):
    """Mock a service call that may time out."""
    start = time.time()
    print(f"Calling {service_name}...")
    
    # Simulate service latency (randomized for realism)…

16 0 Open

Microservices patterns medium

How to implement a circuit breaker in Python

A Python CircuitBreaker class that tracks failures, opens after a threshold, and retries after a timeout.

circuit-breaker resilience microservices

Python

class CircuitBreaker:
    def __init__(self, failure_threshold=3, timeout=5):
        self.failure_threshold = failure_threshold
        self.timeout = timeout
        self.failure_count = 0
        self.last_failure_time = None
        self.state = "CLOSED"

    def call(self, mock_downstream):
        if self.state …

13 0 Open

Microservices patterns easy

Retry idempotent GET requests in Python

A Python function that retries an idempotent GET request a fixed number of times with a delay between attempts, raising a RuntimeError only after all retries fail.

retry idempotent urllib

Python

import time
import urllib.error
import urllib.request
from http.client import HTTPException

def fetch_with_retry(url, max_retries=3, delay=1.0):
    for attempt in range(1, max_retries + 1):
        try:
            with urllib.request.urlopen(url, timeout=5) as response:
                return response.read().decode…

14 0 Open

Microservices patterns easy

Strangler Fig Migration Pattern in Python

Gradually reroute calls from a legacy service to a modern replacement using a runtime switch and feature detection.

migration facade microservices

Python

from dataclasses import dataclass

@dataclass
class PaymentService:
    def process(self, amount: float) -> str:
        return f"Legacy processed ${amount:.2f}"

class StranglerFig:
    def __init__(self):
        self._new_service = None

    def attach_new(self, service):
        self._new_service = service

    de…

14 0 Open

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