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How to Stage All Modified Files with git add -u in Python
Runs git add -u from Python to stage all modified and deleted tracked files, then prints the short status.
import subprocess
def stage_all_modified_files(repo_path="."):
"""Run git add -u to stage all modified and deleted tracked files."""
result = subprocess.run(
["git", "add", "-u"],
cwd=repo_path,
capture_output=True,
text=True,
)
if result.returncode != 0:
print…How to generate and parse an interactive rebase TODO list in Python
Generate a Git interactive rebase TODO list from commit data and parse it back into structured records.
import re
from collections import namedtuple
Commit = namedtuple("Commit", ["hash", "subject"])
def generate_rebase_todo(commits, action="pick"):
todo_lines = []
for i, commit in enumerate(commits):
if i == 0 and action == "reword":
todo_lines.append(f"reword {commit.hash} {commit.subject…How to sync a fork with upstream in Python
Run git fetch and merge commands from Python with subprocess to sync a forked repository with upstream/main.
import subprocess
import sys
def sync_fork_with_upstream():
"""Simulate syncing a forked repo with upstream via git commands."""
# Mock git operations: pretend to fetch from upstream and merge into main
fetch_result = subprocess.run(
["git", "fetch", "upstream"],
capture_output=True, tex…Python Script to Rotate a Leaked API Key
A checklist-driven Python script that scans a codebase for a leaked API key, replaces it with a new one, and prints a step-by-step rotation checklist.
#!/usr/bin/env python3
"""Checklist for rotating a leaked API key across a codebase."""
import re
from pathlib import Path
CHECKLIST = [
"Identify all files containing the leaked key",
"Generate a new key with sufficient entropy",
"Update the secret storage/CI environment variables",
"Replace the ol…Show Blame Line Author with subprocess in Python
This Python script runs git blame --line-porcelain via subprocess and counts how many lines each author owns in a file.
import subprocess
from collections import Counter
def get_blame_authors(file_path):
"""Extract author names from git blame output using subprocess."""
result = subprocess.run(
["git", "blame", "--line-porcelain", file_path],
capture_output=True,
text=True,
check=True,
)
…Build a Recipe Runner Mock in Python
A Python script that mocks a command runner recipe system: maps recipe names to shell commands, executes them with subprocess, and prints the output and exit code.
import subprocess
import sys
def run_recipe(recipe: str) -> None:
"""Simulate a command runner recipe by printing the command and exit code."""
print(f"Running recipe: {recipe}")
result = subprocess.run(recipe, shell=True, capture_output=True, text=True)
print(f"Exit code: {result.returncode}")
i…How to Define Nox Sessions in Python
Automate repetitive tasks like testing and linting with reusable Nox sessions.
import nox
@nox.session(python=["3.9", "3.10"])
def tests(session):
session.install("pytest")
session.run("pytest")
@nox.session(python="3.9")
def lint(session):
session.install("ruff")
session.run("ruff", "check", ".")
if __name__ == "__main__":
print("Nox sessions defined: tests, lint")
…How to Mock Fabric Connections in Python for Task Testing
Create a lightweight MockConnection class to replace fabric.Connection and test task functions without SSH.
from fabric import Connection
class MockConnection:
"""Minimal mock of fabric.Connection for task testing."""
def __init__(self):
self.commands = []
def run(self, command, **kwargs):
self.commands.append(command)
return f"OK: {command}"
def deploy(conn):
"""Deploy the app:…How to Mock a PEP 517 Build Backend in Python
Use unittest.mock.Mock to simulate a PEP 517 backend interface, stub build hooks, and verify calls for package build automation.
import json
from unittest.mock import Mock
# Simulate a PEP 517 backend interface
class Pep517Backend:
def build_wheel(self, wheel_directory, config_settings=None, metadata_directory=None):
return f"{wheel_directory}/mock_package-1.0.0-py3-none-any.whl"
def get_requires_for_build_wheel(self, config_s…How to Mock a semantic-release Changelog in Python
This Python code simulates a semantic-release changelog generator, grouping commits by type and formatting them into a markdown changelog.
import json
from datetime import datetime
class SemanticReleaseChangelog:
def __init__(self, version, commits):
self.version = version
self.commits = commits
self.release_date = datetime.now().isoformat()
def generate_changelog(self):
grouped = {}
for commit in self.c…Lint a Dockerfile with a Mock Hadolint in Python
A lightweight Python script that simulates hadolint by scanning Dockerfile text for common lint rules and printing violations.
import subprocess
import tempfile
from pathlib import Path
def lint_dockerfile(content: str) -> list[str]:
"""Mock hadolint by checking a few rules and returning violations."""
violations = []
lines = content.splitlines()
for idx, line in enumerate(lines, start=1):
stripped = line.strip()
…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…How to Flag Unexpected Diff Changes in Python
Compares two snapshot lists, detects unexpected differences, and returns a flag indicating whether the snapshot should be updated.
import difflib
def snapshot_diff(before, after, intentional_changes=None):
"""Compare snapshots and flag only unexpected differences."""
intentional_changes = intentional_changes or set()
diff = list(difflib.unified_diff(before, after, lineterm=""))
has_unexpected = False
for line in diff:
…Rotate Log Files by Size in Python
A mock log rotation script that renames log files exceeding a size threshold, appending numbered backups.
import os
from pathlib import Path
def rotate_logs(directory: str, max_size: int = 100) -> None:
"""Rotate log files that exceed max_size bytes."""
log_dir = Path(directory)
for log_file in sorted(log_dir.glob("*.log"), key=lambda p: str(p)):
if log_file.stat().st_size > max_size:
for …How to Mock a File Source Watch Directory in Python
Poll a directory for new files and log changes, simulating a watch directory for data ingestion patterns.
import os
import time
from pathlib import Path
def watch_directory(dir_path: str, poll_interval: float = 1.0, max_iterations: int = 5):
"""
Mock a file-source watch directory by polling for changes.
Returns new files detected during each poll cycle.
"""
directory = Path(dir_path)
directory.mk…How to Do Random Search for Hyperparameter Tuning in Python
A mock random search that samples hyperparameter combinations from a grid and ranks them by a dummy score, with a reproducible seed.
import random
# Mock random search over a small hyperparameter grid
param_grid = {
"learning_rate": [0.001, 0.01, 0.1],
"batch_size": [16, 32, 64],
"num_layers": [1, 2, 3]
}
def random_search(grid, n_iter=5, seed=42):
"""Perform random search over a hyperparameter grid."""
random.seed(seed)
k…Automate Semantic Versioning with Conventional Commits in Python
Automatically bump a semantic version based on conventional commit messages (feat, fix, BREAKING CHANGE) and write the new version to a file.
import re
from pathlib import Path
def get_next_version(current: str, commit_messages: list[str]) -> str:
"""Return the next semantic version based on conventional commit messages."""
major, minor, patch = map(int, current.split("."))
if any(msg.startswith("BREAKING CHANGE") for msg in commit_messages):
…How to Deploy Staging Then Production in Python
Walk through a staged deployment mock that promotes from staging to production in sequence with Python.
import time
def deploy_environment(name: str) -> None:
print(f"Deploying to {name}...")
time.sleep(0.1)
print(f"Deployed to {name} ✔")
def deploy_staging_then_prod() -> None:
environments = ["staging", "production"]
for env in environments:
deploy_environment(env)
if env == "stagi…Browse by section
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