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Monitor Website Uptime with Python
Periodically check if a website is reachable and its HTTP status is 200, logging the status with timestamps.
import requests
import time
def check_website(url):
try:
response = requests.get(url, timeout=5)
if response.status_code == 200:
return True
else:
return False
except requests.ConnectionError:
return False
except requests.Timeout:
return Fals…Schedule Daily Task in Python
Use the schedule library to queue a daily task at a fixed time, then simulate a loop that checks for pending jobs.
import schedule
import time
from datetime import datetime
def daily_task():
print(f"Task executed at {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}")
schedule.every().day.at("10:30").do(daily_task)
if __name__ == "__main__":
for _ in range(3):
schedule.run_pending()
time.sleep(1)How to Track Checkpoint Offset After Batch Commit in Python
A batch processor that tracks the last successfully committed offset after processing records in batches, advancing the checkpoint only when each batch commits successfully.
import json
from typing import Any
class BatchProcessor:
"""Tracks checkpoint offset after committing batches."""
def __init__(self, batch_size: int = 3):
self.batch_size = batch_size
self.offset = 0 # last successfully committed offset (exclusive)
self.total_committed = 0
def …How to Validate Data in a Python Pipeline
A helper module to validate common record types — email, positive integer, and non-empty string list — before processing data in a pipeline.
from typing import Any, Iterable
def is_valid_email(email: str) -> bool:
"""Basic email check: one '@', no spaces, dot after '@'."""
if "@" not in email or " " in email:
return False
local, _, domain = email.partition("@")
return bool(local) and "." in domain
def is_positive_int(value: Any)…Fetch Pull Rebase Workflow Script in Python
A Python script that automates the git fetch, checkout, and pull with rebase workflow using subprocess.
import subprocess
import sys
def run_git_command(args: list[str]) -> str:
"""Run a git command and return its stdout, or raise on failure."""
result = subprocess.run(
["git", *args],
capture_output=True,
text=True,
check=False,
)
if result.returncode != 0:
prin…How to Create a Git Branch if it Doesn't Exist in Python
Utility script that checks if a Git branch exists locally and either creates it or checks it out, with error handling.
import subprocess
import sys
def ensure_branch(branch_name):
"""Create a Git branch if it doesn't exist, otherwise checkout it."""
try:
# Check if the branch exists locally
result = subprocess.run(
["git", "branch", "--list", branch_name],
capture_output=True,
…How to Mock git sparse-checkout Paths in Python
Simulates git sparse-checkout configuration by writing desired paths to the sparse-checkout file without running git commands.
import subprocess
from pathlib import Path
import tempfile
def configure_sparse_checkout(repo_dir: Path, paths: list[str]) -> list[str]:
"""Simulate sparse checkout configuration by returning the paths that would be set."""
sparse_checkout_file = repo_dir / ".git" / "info" / "sparse-checkout"
sparse_chec…How to Check an SCP Deny List in Python
Load a JSON SCP policy file, extract the deny_list, and check if a target ARN is denied.
import json
from pathlib import Path
def evaluate_scp_deny_list(policy_path: Path, target_path: str) -> bool:
policy = json.loads(policy_path.read_text())
deny_list = policy.get("deny_list", [])
return target_path in deny_list
if __name__ == "__main__":
policy_file = Path("scp_policy.json")
pol…How to Enforce Tag Policies on AWS Resources in Python
Build a reusable Python class that checks AWS resources against a required-tag policy and reports compliance with missing tags.
import json
from dataclasses import dataclass, field
from typing import Dict, List
@dataclass
class Resource:
arn: str
tags: Dict[str, str] = field(default_factory=dict)
class TagPolicyEnforcer:
def __init__(self, required_tags: List[str]):
self.required_tags = set(required_tags)
def enfor…How to Evaluate Mock NACL Rules in Python
Simulate numbered AWS Network ACL rule evaluation with HMAC integrity checks on request payloads.
import base64
import json
import hmac
import hashlib
def evaluate_mock_rule(rule_number, request_data, secret):
"""
Simulates evaluating an NACL-like numbered rule by:
1. Checking if the rule number exists in the mock policy.
2. Computing an HMAC over the request payload for integrity.
"""
# M…How to Mock ELB Target Health Status in Python
Simulate AWS Elastic Load Balancer target health checks with a Python dict that mutates status and healthy host counts.
from random import randint
def elb_target_mock_status(target_id, healthy=True):
targets = {
1: {"Id": "i-001", "Status": "healthy", "Port": 80, "HealthyHostCount": 1},
2: {"Id": "i-002", "Status": "unhealthy", "Port": 80, "HealthyHostCount": 0},
3: {"Id": "i-003", "Status": "healthy", "Por…Mock AWS Spot Instance Interruption Handler in Python
A Python class that simulates AWS Spot instance interruption checks, handling the 10% chance of termination, logging state-saving, and storing notice details.
import time
import random
class SpotInstanceHandler:
def __init__(self, instance_id):
self.instance_id = instance_id
self.interruption_notices = []
def start(self):
print(f"Spot instance {self.instance_id} started")
def check_interruption(self):
# Simulate random interrup…How to Mock docker compose up Healthcheck in Python
Simulate docker compose up with a healthcheck cycle using Python loops, delays, and simulated service statuses.
import subprocess
import time
def run_healthcheck():
"""Mock a docker compose up with a healthcheck cycle."""
services = ["web", "db", "cache"]
print("Starting docker compose services...")
for service in services:
print(f"[{service}] starting...")
time.sleep(0.1)
print(f"[…How to Mock isort Output to Test Import Sorting in Python
Uses isort with check mode and a unittest mock to verify whether a Python source string has correctly sorted imports.
import isort
from unittest.mock import patch
code = """
import os
import sys
import json
import pathlib
"""
def check_imports_sorted(code_str):
with patch("isort.api.output") as mock_output:
isort.code(code_str, check=True, show_diff=True)
return mock_output.called
if __name__ == "__main__":
…How to Type Check a Mock with pyright in Python
Shows how pyright validates a mock function against a TypedDict and Callable signature before runtime.
from typing import TypedDict, Callable
class User(TypedDict):
id: int
name: str
def get_user_name(user_id: int, get_user: Callable[[int], User]) -> str:
user = get_user(user_id)
return user["name"]
def mock_get_user(user_id: int) -> User:
return {"id": user_id, "name": f"User {user_id}"}
if…Makefile Targets for lint, test, and build in Python
This Python script defines common Makefile targets (lint, test, build) as subprocess commands, printing each target's command and executing them with error checking.
import subprocess
TARGETS = {
"lint": ["ruff", "check", "."],
"test": ["pytest", "-q"],
"build": ["python", "-m", "build"],
}
def run(target: str) -> None:
if target not in TARGETS:
raise ValueError(f"Unknown target: {target}")
print(f"Running {target}...")
subprocess.run(TARGETS[tar…pytest mark slow skip integration
Uses pytest markers to select fast tests, skip unfinished ones, and run integration checks with verbose output.
import pytest
def test_fast():
assert 1 + 1 == 2
@pytest.mark.slow
def test_slow():
import time
time.sleep(1)
assert 5 * 5 == 25
@pytest.mark.skip(reason="Not ready for production")
def test_skipped():
assert 2 + 2 == 5
@pytest.mark.integration
def test_integration():
database = {"users": […Fix and Test a Regression Bug in Python with Unit Tests
This code implements a circle area function that raises ValueError for negative radii, then runs basic tests and a regression check for that edge case.
import math
def calculate_area(radius):
"""Calculate the area of a circle given its radius."""
if radius < 0:
raise ValueError("Radius cannot be negative")
return math.pi * radius ** 2
def main():
test_cases = [0, 1, 2.5, 5, 10]
print("Circle Area Calculator")
print("-" * 30)
…How to Parametrize pytest Tests with Multiple Input Cases in Python
This code shows how to use pytest's @pytest.mark.parametrize decorator to run the same test function across multiple input-output combinations, checking that an add function behaves correctly for each case.
import pytest
def add(a, b):
return a + b
@pytest.mark.parametrize("a,b,expected", [
(1, 2, 3),
(5, 5, 10),
(-1, 1, 0),
(0, 0, 0),
(10, -3, 7),
])
def test_add(a, b, expected):
assert add(a, b) == expected
if __name__ == "__main__":
pytest.main([__file__, "-v"])How to Test Hypotheses with Property-Based Check in Python
A Python search that checks an integer property (palindrome divisible by digit sum) and returns the first counterexample within a range, with exactly reproduced output from the code.
def is_property_satisfied(n):
"""
Demonstrates a mathematically inspired property:
checks whether n is both a palindrome and divisible by its digit sum.
"""
s = str(n)
if s != s[::-1]:
return False
digit_sum = sum(int(d) for d in s)
return digit_sum != 0 and n % digit_sum == 0
…How to Use Literal Type Hints in Python
Use typing.Literal to restrict a function parameter to specific allowed string values and get static type checking.
from typing import Literal
def get_status_message(status: Literal["active", "inactive", "pending"]) -> str:
"""Return a message based on the status value."""
if status == "active":
return "Account is active"
elif status == "inactive":
return "Account is inactive"
else:
return "…How to Use TypedDict for Structured Dict Typing in Python
Define and use TypedDict to add type hints to dictionaries, improving code clarity and enabling static type checking in your Python projects.
from typing import TypedDict
class User(TypedDict):
name: str
age: int
email: str
def greet(user: User) -> str:
return f"Hello {user['name']}, age {user['age']}, contact {user['email']}"
if __name__ == "__main__":
alice: User = {"name": "Alice", "age": 30, "email": "alice@example.com"}
pr…How to Use Union Type Hints in Python
This code demonstrates how to use Union type hints to specify that a parameter can accept multiple types (int, float, str) and handle them accordingly.
from typing import Union
def process_value(value: Union[int, float, str]) -> str:
if isinstance(value, (int, float)):
return f"Number: {value * 2}"
return f"String: {value.upper()}"
if __name__ == "__main__":
print(process_value(10))
print(process_value(3.14))
print(process_value("hello"))How to Validate Dataclass Fields with Python Type Hints
A beginner-friendly helper that checks if instance attributes match their declared type hints using dataclasses and get_type_hints.
from typing import Any, TypeVar, get_type_hints
from dataclasses import dataclass
T = TypeVar("T")
@dataclass
class User:
name: str
age: int
email: str
def validate_fields(obj: Any) -> dict[str, bool]:
"""Check if object attributes match declared type hints."""
hints = get_type_hints(obj.__class…Browse by section
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