runner

Version: 9.3.0

wexample-runner gives Python ≥ 3.10 code a single execute(cmd) call that runs shell commands on the local machine via subprocess, on a remote server over SSH (paramiko), or inside a Docker container — without the caller branching on the target environment. Every runner follows the same build / start / stop / destroy lifecycle and returns a RunnerResult dataclass carrying stdout, stderr, and exit_code. It targets developers who automate operations across mixed execution environments and want one interface that works regardless of where the command lands.

Table of Contents

• Installation
• Quickstart
• Tests
• Architecture
• Integration in the Suite
• Dependencies
• Versioning & Compatibility Policy
• License
• About us
• Known Limitations & Roadmap
• Status & Compatibility
• Useful Links
• Migration Notes

Installation

pip install wexample-runner

Requires Python >=3.10.

Quickstart

Install the package:

pip install wexample-runner

LocalRunner runs commands on the local machine with no setup:

from wexample_runner.runner.local_runner import LocalRunner

runner = LocalRunner()
result = runner.execute(["echo", "hello"])

print(result.stdout)       # hello\n
print(result.exit_code)    # 0
print(result.is_success()) # True

execute accepts a list of arguments or a plain shell string and always returns a RunnerResult dataclass carrying stdout, stderr, and exit_code.

To raise instead of checking the exit code manually:

result.raise_on_error()

Tests

This project uses pytest for testing and pytest-cov for code coverage analysis.

Installation

First, install the required testing dependencies:

.venv/bin/python -m pip install pytest pytest-cov

Basic Usage

Run all tests with coverage:

.venv/bin/python -m pytest --cov --cov-report=html

Common Commands

# Run tests with coverage for a specific module
.venv/bin/python -m pytest --cov=your_module

# Show which lines are not covered
.venv/bin/python -m pytest --cov=your_module --cov-report=term-missing

# Generate an HTML coverage report
.venv/bin/python -m pytest --cov=your_module --cov-report=html

# Combine terminal and HTML reports
.venv/bin/python -m pytest --cov=your_module --cov-report=term-missing --cov-report=html

# Run specific test file with coverage
.venv/bin/python -m pytest tests/test_file.py --cov=your_module --cov-report=term-missing

Viewing HTML Reports

After generating an HTML report, open htmlcov/index.html in your browser to view detailed line-by-line coverage information.

Coverage Threshold

To enforce a minimum coverage percentage:

.venv/bin/python -m pytest --cov=your_module --cov-fail-under=80

This will cause the test suite to fail if coverage drops below 80%.

Architecture

The package is organised around one abstract base, one result dataclass, one optional config dataclass, one registry, and five concrete runner classes. Every public entry point funnels through AbstractRunner.execute() and every response comes back as a RunnerResult.

Abstract base

src/wexample_runner/runner/abstract_runner.py defines the contract every runner implements.

Lifecycle — four methods cover the full arc of an environment:

ensure_running() composes build() then start(). The class also implements the context manager protocol: __enter__ calls ensure_running(), __exit__ calls stop() and, when ephemeral=True, destroy().

Execution — the one abstract method every subclass must provide:

def execute(
    self,
    cmd: list[str] | str,
    workdir: str | None = None,
    env: dict[str, str] | None = None,
) -> RunnerResult:

Result

src/wexample_runner/runner_result.py is a plain dataclass. Every execute() call returns one:

@dataclass
class RunnerResult:
    exit_code: int
    stderr: str
    stdout: str

Two helpers cover the common patterns: is_success() returns exit_code == 0; raise_on_error() raises RuntimeError on non-zero exit, embedding stderr or stdout in the message.

Configuration

src/wexample_runner/runner_config.py is an optional declarative layer for Docker-based runners. It groups the fields a runner needs at construction time — dockerfile, image_name, mount_path, container_workdir, volumes, and ephemeral — into one object a caller can pass around rather than threading individual keyword arguments.

Registry

src/wexample_runner/runner_registry.py holds named AbstractRunner instances. It extends SharedRegistry from wexample_helpers, which provides a class-level singleton via .shared() alongside ordinary instantiation for isolated registries.

Callers register a pre-configured runner under an explicit string key and retrieve it by the same key:

RunnerRegistry.shared().register(runner, key="prod")
runner = RunnerRegistry.shared().get_or_raise("prod")

status() introspects every registered runner and returns a list of dicts with name, type, is_built, is_running, and ephemeral.

Concrete runners

LocalRunner

src/wexample_runner/runner/local_runner.py runs commands on the local machine through wexample_helpers.helper.shell.shell_run. Both is_built and is_running always return True; the runner has no lifecycle to manage. execute() captures stdout and stderr with capture=True and returns them in a RunnerResult.

SshRunner

src/wexample_runner/runner/ssh_runner.py wraps a paramiko.SSHClient. The connection is opened in start() and closed in stop(). execute() assembles a shell string: if cmd is a list it joins it with shlex.join, prepends cd {workdir} && when a workdir is given, and prefixes environment variables as KEY=value pairs before calling exec_command. is_running inspects the paramiko transport's active state.

AbstractDockerRunner

src/wexample_runner/runner/abstract_docker_runner.py provides the shared docker exec logic used by both Docker subclasses. execute() builds a docker exec invocation:

docker exec [--user U] [-w workdir] [-e K=V ...] <container_name> <cmd>

It also provides rebase_path(host_path), which translates an absolute host path to its equivalent inside the container by matching it against the deepest registered volume mount. The _find_mount_for helper picks the longest matching mount so nested mounts take priority.

DockerRunner

src/wexample_runner/runner/docker_runner.py owns its container end-to-end. build() calls docker_build_image when the image does not exist yet. start() creates the container with docker_run_container (pinning it to the current host uid:gid) or restarts an existing stopped one with docker_start_container. destroy() stops the container, removes it, then removes the image. is_built checks whether the image exists via docker_image_exists.

DockerAttachedRunner

src/wexample_runner/runner/docker_attached_runner.py attaches to a container it does not own. start() raises RuntimeError if the container is not already running; stop() is a no-op; destroy() always raises to prevent accidental removal. rebase_path() extends the base implementation by lazily loading the container's actual mounts from Docker via docker_container_mounts when no volumes have been configured.

Call path

A command reaches the target environment in four steps:

1. Optionally prepare — the caller calls ensure_running() (or uses the runner as a context manager). This triggers build() then start(). For LocalRunner and SshRunner.build() these are no-ops; for DockerRunner they build the image and create or restart the container; for SshRunner.start() the paramiko connection is opened.

2. Call execute(cmd) — the caller passes a list of arguments or a raw shell string, with optional workdir and env overrides.

3. Backend dispatch — LocalRunner forwards to shell_run; SshRunner assembles a shell string and calls exec_command; the Docker runners assemble a docker exec invocation and forward it to shell_run.

4. Result — the backend's stdout, stderr, and exit code are wrapped in a RunnerResult and returned to the caller unchanged.

Integration in the Suite

This package is part of the Wexample Suite — a collection of high-quality, modular tools designed to work seamlessly together across multiple languages and environments.

Related Packages

The suite includes packages for configuration management, file handling, prompts, and more. Each package can be used independently or as part of the integrated suite.

Visit the Wexample Suite documentation for the complete package ecosystem.

Dependencies

• paramiko: >=3.0.0
• wexample-helpers: >=19.1.0

Versioning & Compatibility Policy

Wexample packages follow Semantic Versioning (SemVer):

• MAJOR: Breaking changes
• MINOR: New features, backward compatible
• PATCH: Bug fixes, backward compatible

We maintain backward compatibility within major versions and provide clear migration guides for breaking changes.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Free to use in both personal and commercial projects.

About us

Wexample stands as a cornerstone of the digital ecosystem — a collective of seasoned engineers, researchers, and creators driven by a relentless pursuit of technological excellence. More than a media platform, it has grown into a vibrant community where innovation meets craftsmanship, and where every line of code reflects a commitment to clarity, durability, and shared intelligence.

This packages suite embodies this spirit. Trusted by professionals and enthusiasts alike, it delivers a consistent, high-quality foundation for modern development — open, elegant, and battle-tested. Its reputation is built on years of collaboration, refinement, and rigorous attention to detail, making it a natural choice for those who demand both robustness and beauty in their tools.

Wexample cultivates a culture of mastery. Each package, each contribution carries the mark of a community that values precision, ethics, and innovation — a community proud to shape the future of digital craftsmanship.

Known Limitations & Roadmap

Current limitations and planned features are tracked in the GitHub issues.

See the project roadmap for upcoming features and improvements.

Status & Compatibility

Maturity: Production-ready

Python Support: >=3.10

OS Support: Linux, macOS, Windows

Status: Actively maintained

Useful Links

• Homepage: https://github.com/wexample/python-runner
• Documentation: docs.wexample.com
• Issue Tracker: https://github.com/wexample/python-runner/issues
• Discussions: https://github.com/wexample/python-runner/discussions
• PyPI: pypi.org/project/wexample-runner

Migration Notes

When upgrading between major versions, refer to the migration guides in the documentation.

Breaking changes are clearly documented with upgrade paths and examples.