## Web Server
- **Solutions**: 
    - Apache (with mod WSGI)
    - or nginx (with gunicorn I guess)
- **Goal/Function**:
    - Serves content
    - handels HTTP requests etc.
    - handels encryption
        - with SSL/TLS and Let's encrypt 
    - serves forms for user request and inputs
    - has copy of Joblist to display those for the user according to requests etc.
    - talks to the Manager service
    - Users CANNOT talk directly with the manager
    - has list of all currently running user sessions (maybe used for authentication)

## Application Server
- **Solution**: Flask

### Authentication and session management
- **Solutions**:
    - Flask-Login (minimal)
    - Flask-Session (maybe a bit more functions)
- **Goal/Function**
    - handels both internal and external users
- Relational Database
    - **Solutions**_
        - PostgreSQL
        - MariaDB
- Object Relational Mapper
    - **Solutions**:
        - Flask-SQLAlchemy

### Manager Service:
- Part of the Application Server
- manages also files on file server 
- Joblist
    - **Solution**:
        - http://www.celeryproject.org/
        - Thread safe
        - Scheduling
        - Ressource management
- REST API
    - **Solution**
        - Flask internal
        - and also part of celery
    - **Goal/Function**
        - Passes requests to the joblist/celery
        - Functions:
            - create_job
            - delete_job
            - get_job (JSON Object or metadata or both?)
            - alter_job
- Mail notifications
    - **Solution**: 
        - Flask-Mail
    - **Goal/Function**
        - Sends Mails to users if a OCR job has finished

## OCR containers with tesseract
- **Goal/Function**
    - celery checks joblists continiously
    - job start commands will be passed to the containers
    - jobs will be started accordingly

## Compute pool: Docker Cluster
- **Solutions**: 
    - Kubernetes
    - swarm 
- **Goal/Function**    
    - How to handle job and resource management for user Jobs and processes.
    - gets requests and tasks from the manager

## File Server (Scans, pdfs etc.)
- **Goal/Function**
    - stores user input and
    - output files
    - Upload
    - Download
- **Solutions**:  
    - WebDAV/Samba/Docker Volume

# Additional Functions

## Information retrival system
- **Solutions**: 
    - CEQUL with CWB Server
    - Lucene 
- **Functions/Goals**
    - KWIC
    - KWIC with complex querys (POS, NER, Lemma querys)
    - Frequency lists
    - n-grams
    - complex n-grams
    - etc.