heros-boss 0.6.20

Configuration driven object/HERO starter

BOSS Object Starter Service (BOSS)

BOSS is a service that instantiates Python objects as HEROs based on a JSON configuration. The configuration can be read from a file, a URL (e.g. from a CouchDB), or from an environment variable. Essentially, BOSS allows you to quickly wrap your arbitrary Python object as a HERO and to run it.

:open_book: Below is a quick walkthrough of the basic functionalities. You find the full documentation here.

As an example, let's take an object available in the Python standard library, the FTP class from the ftplib module. To make BOSS create an object of the class FTP, we need the following configuration:

{
     "_id": "test-json-ftp",
     "classname": "ftplib.FTP",
     "arguments": {
          "host": "ftp.us.debian.org"
     }
}

python -m boss.starter -u file:///absolute/path/to/ftp.json

Now our object is available in the default realm of our HEROS network. It can be viewed with any HEROObserver. For a graphical view, use HERO-Monitor.

Exposing the BOSS instance itself

To expose the BOSS instance as a HERO, use the --expose command line flag:

python -m boss.starter --expose -u file:///absolute/path/to/ftp.json

When the BOSS instance is exposed, HEROs can be dynamically added and removed by the calling the add_hero(config: dict) and remove_hero(name: str) methods. This allows to run BOSS without any initial configuration and manage the running HEROs from a remote service.

By default, the instance receives a unique name consisting of the hostname and a UUID. To change the name, use the --name argument:

python -m boss.starter --expose --name my_test_boss -u file:///absolute/path/to/ftp.json

Using the asyncio main loop

BOSS starts a asyncio loop that the started objects can use. If your object expects to get the loop object in the constructor you can define attach it to the boss loop through the magic string "@_boss_loop" as in the following example:

{
  "_id": "statemachine",
  "classname": "herostools.actor.statemachine.HERODatasourceStateMachine",
  "arguments": {
    "loop": "@_boss_loop",
    "http_port": 9090,
    "bind_address": "localhost",
    "labels": {"system": "heros"}
  }
}

Docker

A convenient way to deploy BOSS is inside of a Docker container. You can find pre-built containers images in our Docker registry.

You can also build the BOSS Docker image yourself from the Dockerfile in the repository:

docker build -t atomiq/boss .

A BOSS Docker service can be started with the following compose file

version: '2'

services:
  httpclient:
    image: registry.gitlab.com/atomiq-project/boss:latest
    restart: always
    network_mode: host
    environment:
     - |
       BOSS1=
       {
        "_id": "docker-env-ftp",
           "classname": "ftplib.FTP",
           "arguments": {
                "host": "ftp.us.debian.org"
           }
       }
    command: python -m boss.starter -e BOSS1

Additionally, also specifying a file or URL is possible, such that (mounted) JSON files in the Docker container or web URLs can be used as configuration sources. Note that the -e and -u options can be specified multiple times to define several objects that should be instantiated by the BOSS.