Source code for seaworthy.checks

"""
Checks and test decorators for skipping tests that require Docker to be
present.
"""

import unittest
from contextlib import contextmanager

import docker

from requests.exceptions import ConnectionError


@contextmanager
def docker_client():
    """
    A context manager that creates and cleans up a Docker API client.

    In most cases, it's better to use :class:`~seaworthy.helpers.DockerHelper`
    instead.
    """
    client = docker.client.from_env()
    yield client
    client.api.close()


def docker_available():
    """
    Check if Docker is available and responsive.
    """
    with docker_client() as client:
        try:
            return client.ping()
        except ConnectionError:  # pragma: no cover
            return False


def dockertest():
    """
    Skip tests that require Docker to be available.

    This is a function that returns a decorator so that we don't run arbitrary
    Docker client code on import. This implementation only works with tests
    based on :class:`unittest.TestCase`. If you're using pytest, you probably
    want :func:`seaworthy.pytest.dockertest` instead.
    """
    return unittest.skipUnless(docker_available(), 'Docker not available.')