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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 Create a Git Commit with Message Template in Python
Run a git commit from Python using a standardized message template built from a commit type and description.
import subprocess
import sys
def commit_with_template(commit_type: str, description: str) -> None:
message = f"{commit_type}: {description}"
try:
subprocess.run(["git", "commit", "-m", message], check=True)
print(f"Committed: {message}")
except subprocess.CalledProcessError as e:
…How to Get Git Status and Log in Python
A beginner-friendly helper that runs git status and git log from Python using subprocess, with safe handling for non-repo directories.
import subprocess
from pathlib import Path
def git_status(path: str = ".") -> str:
"""Return the current git status as a string."""
result = subprocess.run(
["git", "status", "--short"],
cwd=path,
capture_output=True,
text=True
)
return result.stdout.strip() or "No cha…How to List Changed Files in the Last Git Commit with Python
Runs `git diff --name-only HEAD~1 HEAD` via subprocess to list the names of files changed in the most recent commit.
import subprocess
def list_changed_files():
result = subprocess.run(
["git", "diff", "--name-only", "HEAD~1", "HEAD"],
capture_output=True,
text=True,
check=True
)
files = result.stdout.strip().splitlines()
return files
if __name__ == "__main__":
changed = list_cha…How to Mirror a Bare Git Repository Backup in Python
Run a git clone --bare subprocess to create a timestamped bare-repo backup folder with error handling.
import subprocess
import shlex
from pathlib import Path
from datetime import datetime
def mirror_bare_repo(source_url: str, backup_dir: str) -> str:
"""Mirror a bare git repository to a timestamped backup folder."""
backup_path = Path(backup_dir)
backup_path.mkdir(parents=True, exist_ok=True)
timest…How to Parse git status --porcelain Output in Python
This code runs `git status --porcelain` and parses its output into a list of dictionaries with file paths and status descriptions.
import subprocess
def parse_git_status_porcelain():
try:
output = subprocess.check_output(
["git", "status", "--porcelain"],
text=True,
stderr=subprocess.DEVNULL
)
except (subprocess.CalledProcessError, FileNotFoundError):
return []
entries = …How to Push Git Tags to a Remote with Python
Push specified git tags (or all tags) to a remote repository using Python's subprocess module with error handling.
import subprocess
import sys
def push_tags_to_remote(remote: str = "origin", tags: list[str] | None = None) -> None:
"""
Push git tags to a remote repository.
If no tags are given, push all local tags.
"""
if tags:
subprocess.run(["git", "push", remote, *tags], check=True)
else:
…How to Run Git Commands from Python with subprocess
This helper runs `git status --short` and `git log --oneline` from Python, captures their output, and returns readable strings with error handling for non-repo directories.
import subprocess
def git_status():
"""Return a short, human-readable git status."""
try:
output = subprocess.run(
["git", "status", "--short"],
capture_output=True,
text=True,
check=True,
).stdout.strip()
return output if output else "W…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 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…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:…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…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…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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