===== Deconcentrator  =====
let deconcentrator do the "hard" work of checking multiple natural language understanding processing providers. 


==== Table Of Content ====
   - [[wiki:software:beuthbot:deconcentrator#deconcentrator|Deconcentrator]]
   - [[wiki:software:beuthbot:deconcentrator#table_of_content|Table of content]]
   - [[wiki:software:beuthbot:deconcentrator#scope|Scope]]
   - [[wiki:software:beuthbot:deconcentrator#how-to|How To]]
   - [[wiki:software:beuthbot:deconcentrator#authors|Authors]]


==== scope ==== 
be a common endpoint for various nlu providers:

- [[https://rasa.com/docs/rasa/|RASA]]

others aren't implemented yet, but implementation should be trivial: 

- [[https://azure.microsoft.com/de-de/services/cognitive-services/language-understanding-intelligent-service/|Microsoft LUIS]]\\
- [[https://cloud.google.com/natural-language/|Google Cloud NLU]]\\
- [[https://www.ibm.com/watson/services/natural-language-understanding/|IBM Watson NLU]]\\

==== principles ==== 

=== important frameworks/software pieces ===
- [[https://nginx.org|nginx]]: reverse proxy (static files) and uwsgi gateway
- [[https://pypi.org/project/uWSGI/|uWSGI]]: wsgi implementation
- [[https://www.django-rest-framework.org/|Django REST framework]]: REST interfaces, viewsets, generic serialization 
    logic etc.
- [[https://www.djangoproject.com/|Django]]: "The web framework for perfectionists with deadlines." 
- [[https://docs.celeryproject.org/|Celery]]: Distributed task queue for delegating I/O tasks (like doing web requests)
- [[https://www.rabbitmq.com/|RabbitMQ]]: async task queue itself
- [[https://redis.io/|redis]]: django cache, session cache, celery result backend
- [[https://memcached.org/|memcached]]: django cache.
- [[https://www.postgresql.org/|PostgreSQL]]: database backend.
=== important models ===

- `Method`: the abstraction of a function to retrieve an actual NLU processing result.
- `Provider`: the actual provider, which is doing some kind of NLU processing. 
- `Strategy`: how to select a `Provider` for a specific `Objective`
- `Objective`: kind of a task that has to be done. It's the main entry-point, user-supplied. It contains the actual 
    payload which has to be NLU processed and selects an strategy.
- `Job`: the `Strategy` creates jobs from an `Objective`. Each job then has a specific `Provider` to use for processing.
- `Result`: the outcome of asking a `Provider`.

=== implementation details ===

- `Objective`, `Job` and `Result` make use of non-abc-dispatching (i. e. dispatching without a common abstract base 
    class). That means:
    - they have a common method with equal signature called `execute()` and are connected to the same `post_save` 
        handler.
    - once an object of one of these classes is `save`d, the `post_save` hook will call that common method. 
    - that method, then, calls the `Strategy` model method for further handling.
    - to avoid infinite recursion, one has to avoid calling `save()` within the `Strategy` method, instead using the 
        `<Model>.objects.filter(...).update(...)`-approach
- the `ViewSet`s design:
    - `Method`s, `Strategy`s, `Job`s and `Result`s can only be read
    - `Provider`s can be CRUD on demand. 
    - `Objective`s can be created and retrieved, but not updated or deleted.

==== how-to ====

The project contains multiple `docker-compose` files; therefore, basically you only have to `docker-compose up` the 
project. 

- You need to build the deconcentrator image in the directory that holds the Dockerfile.
    docker build -t deconcentrator:latest .
- You can use the `management.sh` script to create the required secret files: `./management.sh prepare`; they are required to start the containers.

- You will probably want to create a sym-link named `docker-compose.override.yml` to export the nginx port to the public 
    ln -s docker-compose.production.yml docker-compose.override.yml
- You will probably want to run the migrations; basically it's a `./manage.py migrate` call, which can be done via 
    ./management.sh exec uwsgi /mnt/deconcentrator/manage.py migrate
- To access the admin interface, you'll have to create a superuser account first: 
    ./management.sh exec uwsgi /mnt/deconcentrator/manage.py createsuperuser




==== Authors ====


 **Kai Nessig** - //Initial work// - [[https://github.com/tiberius|GitHub]]

See also the list of [[https://github.com/beuthbot/deconcentrator/graphs/contributors]] who participated in this project.
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