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Python Code Samples

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347 matches
Production deployment patterns easy

How to Mock a SIGTERM Handler in Python

Create a graceful shutdown handler for SIGTERM and SIGINT signals, then test it by simulating a signal delivery without terminating the process.

signals graceful-shutdown sigterm
Python
import signal
import time

class Service:
    def __init__(self):
        self.running = True

    def shutdown(self, signum, frame):
        print(f"Received signal {signum}, shutting down gracefully...")
        self.running = False

    def run(self):
        signal.signal(signal.SIGTERM, self.shutdown)
        sig…
14 0 Open
Production deployment patterns easy

How to Mock a Slow Startup Probe for Fast Testing in Python

This code shows how to replace a slow startup probe's initialization with a mock to make tests run fast and reliably.

mock testing startup-probe
Python
import time
from unittest.mock import Mock, patch


class StartupProbe:
    def __init__(self, init_time):
        self.init_time = init_time
        self.ready = False

    def initialize(self):
        time.sleep(self.init_time)
        self.ready = True
        return self.ready


def run_startup_probe(probe):
    …
16 0 Open
Production deployment patterns easy

How to Mock an Ingress TLS Certificate Manager in Python

Build a mock TLS certificate manager for ingress that issues, checks, and renews certificates with expiry tracking — useful for testing deployment workflows before touching real infrastructure.

tls certificates ingress
Python
import ssl
import socket
from datetime import datetime, timedelta


class TLSCertManager:
    def __init__(self, hostname):
        self.hostname = hostname
        self.certificates = {}

    def request_certificate(self, domain, days_valid=90):
        """Mock a certificate issuance request that stores a cert with e…
16 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_…
15 0 Open
Production deployment patterns easy

How to Roll Back to a Previous Image Tag in Python

A dataclass-based mock registry that tracks image tag history and rolls back to the previous tag, useful for deployment rollback logic.

rollback deployment dataclass
Python
"""Demonstrates a rollback pattern for a Docker-style image tag registry."""

from dataclasses import dataclass, field


@dataclass
class ImageRegistry:
    """A minimal mock registry tracking current tags per image."""

    tags: dict[str, list[str]] = field(default_factory=dict)

    def push(self, image: str, tag: …
14 0 Open
Production deployment patterns easy

How to Simulate a Packer AMI Build in Python

A simple Python class that mimics a Packer AMI build lifecycle — creates a build object, transitions its state to completed, and prints a JSON snapshot.

packer ami mock
Python
import json


class PackerBuildMock:
    def __init__(self, name, ami_id, region="us-east-1", state="pending"):
        self.name = name
        self.ami_id = ami_id
        self.region = region
        self.state = state

    def build(self):
        if self.state == "pending":
            self.state = "completed"
  …
14 0 Open
Production deployment patterns easy

How to build a maintenance mode page in Python

Mock a service maintenance status page that computes remaining downtime and lists affected features from a simple class.

maintenance status datetime
Python
from datetime import datetime

class MaintenanceMode:
    """Mock a maintenance mode status page for a service."""
    
    def __init__(self, service_name: str, scheduled_end: str):
        self.service_name = service_name
        self.scheduled_end = datetime.fromisoformat(scheduled_end)
        self.affected_featur…
14 0 Open
Production deployment patterns easy

How to hide incomplete mock features with a Python feature toggle

A simple decorator-based feature toggle that returns a placeholder when a mock feature is disabled, so incomplete code can ship safely.

feature-toggle decorator mock-data
Python
import functools


class FeatureToggle:
    def __init__(self, enabled=False):
        self.enabled = enabled

    def feature(self, func=None):
        """Decorator to conditionally enable a feature."""
        if func is None:
            return self.feature

        @functools.wraps(func)
        def wrapper(*args,…
12 0 Open
Production deployment patterns easy

How to mock resource request limits in Python

A Python class that simulates CPU and memory limit checks for resource requests, returning clear acceptance or rejection messages.

resource-limits mock class
Python
class ResourceLimits:
    def __init__(self, cpu_limit, memory_limit):
        self.cpu_limit = cpu_limit
        self.memory_limit = memory_limit

    def check_request(self, cpu, memory):
        if cpu > self.cpu_limit:
            return "CPU limit exceeded: {cpu} > {limit}".format(cpu=cpu, limit=self.cpu_limit)
 …
14 0 Open
Production deployment patterns easy

How to simulate GitLab CI stages in Python

Build a lightweight Python mock of GitLab CI pipeline stages to test job sequencing and output locally.

gitlab ci simulation
Python
def mock_gitlab_ci_stages():
    stages = ["build", "test", "deploy"]
    stage_status = {}

    for stage in stages:
        jobs = []

        if stage == "build":
            jobs = ["compile", "package"]
        elif stage == "test":
            jobs = ["unit", "integration", "e2e"]
        elif stage == "deploy":…
15 0 Open
Production deployment patterns easy

How to simulate a database migration init container mock in Python

A mock init container that runs environment checks and a staged database migration job before the main application starts, printing progress to stdout.

init-container migration simulation
Python
```python
class MigrationJob:
    def __init__(self, name, steps):
        self.name = name
        self.steps = steps
        self.current_step = 0
        self.status = "pending"

    def run(self):
        print(f"Initializing migration job: {self.name}")
        for step in self.steps:
            self.current_ste…
16 0 Open

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