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Python Code Samples

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35 matches
Observability & SRE easy

Mocking a Metrics Gauge's set_value Method in Python

Demonstrates using unittest.mock.Mock with wraps to intercept a gauge's set_value call while verifying arguments and preserving real behavior.

unittest mocking metrics
Python
from unittest.mock import Mock

class MetricsGauge:
    def __init__(self, name):
        self.name = name
        self.value = 0.0

    def set_value(self, new_value):
        self.value = float(new_value)
        return self.value

# Usage demonstration with a mock
gauge = MetricsGauge("cpu_usage")
gauge_mock = Mock…
13 0 Open
Microservices patterns easy

How to Mock Eventual Consistency UI Notes in Python

Simulates a UI note that shows local state until a pending server update is confirmed, mocking eventual consistency behavior in distributed systems.

eventual-consistency microservices ui
Python
class EventualConsistencyNote:
    def __init__(self, entity_id, note):
        self.entity_id = entity_id
        self.note = note
        self.confirmed = False
        self.pending_updates = []

    def add_pending_update(self, update):
        self.pending_updates.append(update)

    def confirm_update(self):
    …
17 0 Open
Microservices patterns easy

How to mock a SPIFFE workload identity in Python

Generate a mock SPIFFE ID and token for a workload using a trust domain, namespace, and service account.

spiffe identity microservices
Python
import hashlib
import json
from dataclasses import dataclass, asdict


@dataclass
class SPIFFEIdentity:
    trust_domain: str
    namespace: str
    service_account: str

    @property
    def id(self) -> str:
        return f"spiffe://{self.trust_domain}/ns/{self.namespace}/sa/{self.service_account}"


def mock_workl…
13 0 Open
Microservices patterns easy

How to mock an external service in Python with an anti-corruption facade

This code implements an anti-corruption facade that mocks an external API, allowing client code to interact with a simulated service while keeping the same interface.

microservices testing mocking
Python
class AntiCorruptionFacade:
    """Mocks a real API while keeping the same interface."""
    
    def __init__(self, data_store):
        self._data_store = data_store
        self._calls = []
    
    def get_user(self, user_id):
        self._calls.append(f"get_user({user_id})")
        return self._data_store.get(u…
11 0 Open
ML engineering pipelines easy

Champion Challenger Deployment Mock in Python

Simulates an A/B champion-challenger ML deployment workflow — comparing two mock model accuracies and deciding which to promote to production.

ml deployment champion-challenger
Python
import random
import time

class ModelMocker:
    def __init__(self, name="Model", accuracy=0.85):
        self.name = name
        self.accuracy = accuracy

    def predict(self, data):
        """Simulate prediction with some randomness."""
        time.sleep(0.005)  # simulate compute time
        return 1 if rando…
13 0 Open
A/B testing & experimentation easy

How to Do Random Assignment in Python for A/B Tests

Assign each item to a binary group (0 or 1) with uniform probability using a small reusable function, optionally weighted, for A/B testing mocks.

random ab-testing assignment
Python
import random

def random_assignment_uniform_mock(items, weights=None):
    """Assign each item to a group (0 or 1) with uniform probability."""
    if weights is None:
        # Default: each item independently gets 0 or 1 with 50% probability
        return [random.randint(0, 1) for _ in items]
    # Optional weight…
13 0 Open
A/B testing & experimentation easy

How to Mock an Exposure Event Log Record in Python

Generate a realistic exposure event record with UUID, UTC timestamp, and risk level for testing or experimentation.

mocking events testing
Python
import uuid
from datetime import datetime, timezone


def mock_exposure_event(person_id: str, location: str, duration_minutes: int) -> dict:
    return {
        "event_id": str(uuid.uuid4()),
        "person_id": person_id,
        "location": location,
        "duration_minutes": duration_minutes,
        "timestamp…
16 0 Open
Database scaling & optimization easy

How to mock directory-based sharding in Python

Simulates distributing files into logical shards using a deterministic hash of each filename, mocking how a database might shard rows across nodes.

sharding hash partitioning
Python
import os
import hashlib
from collections import defaultdict
from pathlib import Path


def get_shard_for_key(key: str, num_shards: int) -> int:
    """Return a deterministic shard index (0..num_shards-1) for a key."""
    digest = hashlib.md5(key.encode('utf-8')).hexdigest()
    return int(digest, 16) % num_shards


…
14 0 Open
Auth & security at scale easy

Build a Mock OIDC Userinfo Endpoint in Python with Flask

Create a local mock OIDC userinfo endpoint in Flask that returns a standard JSON user payload, ideal for testing auth flows without a real identity provider.

flask oidc userinfo
Python
from flask import Flask, jsonify

app = Flask(__name__)

@app.route("/userinfo")
def userinfo():
    mock_user = {
        "sub": "1234567890",
        "name": "John Doe",
        "email": "john@example.com",
        "email_verified": True,
        "groups": ["admin", "dev"]
    }
    return jsonify(mock_user)

if __n…
13 0 Open
Production deployment patterns easy

How to Mock a Container Registry in Python

Build an in-memory container registry mock with push, tag listing, and manifest retrieval logic for testing deployment tooling.

containers testing mocking
Python
import json
from collections import defaultdict


class MockRegistry:
    def __init__(self):
        self.repositories = defaultdict(dict)

    def push_image(self, repo: str, tag: str, layers: list[str]) -> None:
        self.repositories[repo][tag] = {
            "layers": layers,
            "size": sum(len(layer…
14 0 Open
Production deployment patterns easy

How to Mock time.sleep in a Python PreStop Hook

This code simulates a Kubernetes PreStop hook that delays shutdown, then mocks time.sleep to verify the hook logic without real delay.

mocking prestop kubernetes
Python
import subprocess
import sys
import time
from unittest.mock import patch

def pre_stop_hook():
    """Simulate a Kubernetes PreStop hook that sleeps before shutdown."""
    print("PreStop hook started: delaying shutdown")
    time.sleep(3)
    print("PreStop hook completed: ready to shutdown")

if __name__ == "__main_…
14 0 Open

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