Reference library

Microservices patterns

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

6 matches

Distributed tracing with contextvars in Python

Propagate trace and span IDs across function calls using contextvars to mock distributed tracing in a single process.

import contextvars
import uuid
import time

_trace_context = contextvars.ContextVar("trace_context", default=None)


class TraceContext:
    def __init__(self, trace_id, parent_span_id):
        self.trace_id = trace_id
        self.parent_span_id = parent_span_id
        self.span_id = uuid.uuid4().hex[:16]
        s…

13 0 Open

Microservices patterns easy

Event Sourcing Store in Python: Append-Only Log Mock

Mock an append-only event store in Python — record events, list them, and fetch by ID using a simple list-backed class.

event-sourcing microservices mock

Python

class EventStore:
    def __init__(self):
        self._events = []

    def append(self, event):
        event_id = len(self._events) + 1
        stored_event = {"id": event_id, "data": event}
        self._events.append(stored_event)
        return stored_event

    def get_events(self):
        return list(self._ev…

14 0 Open

Microservices patterns easy

How to Compose Parallel API Calls in Python with asyncio.gather

Compose multiple mock API responses in parallel using asyncio.gather with per-service simulated latency.

asyncio concurrency api

Python

import asyncio
import random
import time

async def mock_api(name: str, delay: float) -> dict:
    await asyncio.sleep(delay)
    return {"service": name, "value": random.randint(1, 100)}

async def fetch_all():
    services = {
        "users": mock_api("users", 0.2),
        "orders": mock_api("orders", 0.3),
      …

15 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

How to implement round-robin load balancing in Python

Implement a client-side round-robin load balancer that distributes requests sequentially across a list of mock servers using itertools.cycle.

load balancing round robin microservices

Python

import itertools
import random


class MockServer:
    def __init__(self, name):
        self.name = name

    def handle_request(self, request_id):
        return f"Server {self.name} handled request #{request_id}"


class RoundRobinLoadBalancer:
    def __init__(self, servers):
        self.servers = servers
       …

14 0 Open

Microservices patterns easy

Mock a Sidecar Logger with Python Metrics

Simulate a sidecar logger that tracks request counts, error rates, and endpoint hits, producing a metrics snapshot.

microservices monitoring metrics

Python

import random
import time
from collections import defaultdict


class SidecarLogger:
    def __init__(self):
        self.metrics = defaultdict(int)
        self.total_requests = 0
        self.error_count = 0

    def log_request(self, endpoint, status_code):
        """Simulate logging a request and updating metrics…

16 0 Open

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