konstruktor

Create and manage Arkitekt deployments — the konstruktor CLI in a wheel, and a Python interface to it.

pip install konstruktor

The wheel carries the CLI itself, so that is the whole install: konstruktor is on your PATH (and python -m konstruktor runs it), and the Python interface below always drives the generator it was released with. Docker has to be running.

Everything that decides what a deployment looks like lives in the CLI. This package runs it and reads back what it wrote — nothing more.

A deployment from Python

from konstruktor import create_hub

hub = create_hub("./hub", services=["rekuest", "mikro"], redeem_tokens=2)

hub.fakts_url                   # http://localhost:<port> — where an app is pointed
hub.redeem_token("my-app")      # what the app trades for a client, with no browser
hub.services["mikro"].url       # http://localhost:<port>/mikro
hub.logs("mikro")
hub.destroy()

A hub can also be made from images instead of names. Each image is asked which service it is, so a client library only has to know the image that hosts it:

hub = create_hub("./hub", service_images=["jhnnsrs/mikro:7"])

Rekuest then runs only if one of the images is Rekuest's.

create_hub builds a self-contained hub: the services you name, and a coordination server of their own, behind one gateway on one port (konstruktor hub create --server local). Nobody has to accept it and nothing leaves the machine. It returns once everything a client opens answers.

Connecting an app to it takes the address and a redeem token:

from arkitekt import App, connect

app = App("my-app", "0.1.0", services=[...])
with connect(app, url=hub.fakts_url, redeem_token=hub.redeem_token("my-app")) as runtime:
    ...

or, for an app in another process, hub.env("my-app") — FAKTS_URL and FAKTS_REDEEM_TOKEN. An app in a container on the hub's own docker network points at http://gateway instead: the hub can be logged into at any address it answers on.

One redeem token serves one app. The coordination server pins a token to the first app that redeems it, so redeem_tokens= is how many apps can connect, and hub.redeem_token(name) hands each name its own.

To run a particular build of a service rather than the one a new hub gets, pin it by its name in the stack: create_hub(..., images={"rekuest": "jhnnsrs/rekuest:1.2.3"}).

With pytest

Installing the package registers a pytest plugin:

import pytest


@pytest.fixture(scope="session")
def hub(konstruktor_hub):
    return konstruktor_hub(services=["rekuest", "mikro"], redeem_tokens=2)


@pytest.mark.konstruktor
def test_my_app(hub):
    ...

• konstruktor_hub is a session-scoped factory. Every hub it makes is destroyed — containers, volumes and folder — when the session ends.
• Tests marked konstruktor are skipped where Docker is not running.
• A failed test gets the hub's container logs attached to its report.
• Hubs live in a registry of their own, so they never show up beside your real ones.
• A session that is killed leaves containers behind; the next session removes them.

Which build of a service a run tests against is usually the job's to say, not the suite's. Set KONSTRUKTOR_IMAGES where the suite runs and every hub created there uses those images, for the services it has:

KONSTRUKTOR_IMAGES=rekuest=jhnnsrs/rekuest:1.2.3,mikro=jhnnsrs/mikro:6.1.0 pytest -m konstruktor

From a source checkout

cargo build -p konstruktor-cli
KONSTRUKTOR_BIN=target/debug/konstruktor PYTHONPATH=python python -m pytest python/tests