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Python Code Samples

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1450 matches
Production deployment patterns easy

How to Replace Fields in an Immutable Dataclass in Python

Create a new copy of a frozen dataclass with selected fields changed, leaving the original unchanged.

dataclasses immutable configuration
Python
from dataclasses import dataclass, replace


@dataclass(frozen=True)
class ServerConfig:
    name: str
    cpu: int = 2
    ram: int = 4096
    tags: tuple = ()


original = ServerConfig("web-01", cpu=4, tags=("env:prod",))
updated = replace(original, ram=8192, tags=("env:prod", "region:us-east"))

print("Original:", …
20 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"
  …
15 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…
17 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,…
14 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)
 …
16 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":…
18 0 Open
Production deployment patterns easy

How to simulate a Jenkins pipeline in Python

Simulate a Jenkins-style pipeline in Python by running sequential stages and checking aggregate success.

jenkins pipeline simulation
Python
def run_stage(name, duration, fn):
    print(f"[Pipeline] Running stage: {name}")
    result = fn()
    print(f"[Pipeline] Stage '{name}' completed in {duration}s -> {result}")
    return result

def build_project():
    print("  compiling source...")
    return "BUILD_OK"

def run_tests():
    print("  executing unit…
18 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
Production deployment patterns easy

PodDisruptionBudget minAvailable in Python

Simulate a Kubernetes PodDisruptionBudget check for minAvailable and maxUnavailable constraints with a Python class.

kubernetes pdb simulation
Python
class PodDisruptionBudget:
    def __init__(self, name, min_available=None, max_unavailable=None):
        self.name = name
        self.min_available = min_available
        self.max_unavailable = max_unavailable

    def check_availability(self, ready_pods):
        if self.min_available is not None:
            ret…
14 0 Open

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