pytest-docker-compose 1.0.1

Waiting for Services to Come Online

The fixture will wait until every container is up before handing control over to the test.

However, just because a container is up does not mean that the services running on it are ready to accept incoming requests yet!

If your tests need to wait for a particular condition (for example, to wait for an HTTP health check endpoint to send back a 200 response), make sure that your fixtures account for this.

Here’s a simple example of a fixture that waits for an HTTP service to come online before starting each test.

import pytest
import typing
from pytest_docker_compose import NetworkInfo
from time import sleep, time

from my_app import ApiClient

pytest_plugins = ["docker_compose"]


@pytest.fixture(name="api_client")
def fixture_api_client(
        docker_network_info: typing.Dict[str, typing.List[NetworkInfo]],
) -> ApiClient:
    # ``docker_network_info`` is grouped by service name.
    service = docker_network_info["my_api_service"][0]

    # Create an instance of our custom application's API client.
    api_client = ApiClient(
        base_url=f"http://{service.hostname}:{service.host_port}/api/v1",
    )

    # Wait for the HTTP service to be ready.
    start = time()
    timeout = 5

    for name, network_info in docker_network_info.items():
        while True:
            if time() - start >= timeout:
                raise RuntimeError(
                    f"Unable to start all container services "
                    "within {timeout} seconds.",
                )

            try:
                if api_client.health_check()["status"] == "ok":
                    break
            except (ConnectionError, KeyError):
                pass

            sleep(0.1)

    # HTTP service is up and listening for requests.
    return api_client


# Tests can then interact with the API client directly.
def test_frog_blast_the_vent_core(api_client: ApiClient):
    assert api_client.frog_blast_the_vent_core() == {
        "status": "I'm out of ammo!",
    }