dane-server 0.3.1

Back-end for the Distributed Annotation 'n' Enrichment (DANE) system

DANE-server

DANE-server is the back-end component of DANE and takes care of task routing as well as the (meta)data storage. A task submitted to DANE-server is registered in a database, and then its .run() function is called. Running a task involves assigning it to a worker via a message queue.

A specific task is run by publishing the task to a RabbitMQ Topic Exchange, on this exchange the task is routed based on its Task Key. The task key corresponds to the binding_key of a worker, and each worker with this binding_key listens to a shared queue. Once a worker is available it will take the next task from the queue and process it.

DANE-server depends on the DANE package for the logic of how to iterate over tasks, and how to interpret a task in general.

Local Installation

DANE-server has been tested with Python 3 and is installable through pip:

pip install dane-server

Besides the python base, the DANE-server also relies on an Elasticsearch server (version 7.9) for storage, and RabbitMQ (tested with version 3.7) for messaging.

After installing all dependencies it is necessary to configure the DANE server, how to do this is described here: https://dane.readthedocs.io/en/latest/intro.html#configuration

The base config for DANE-server consists of the following parameters, which you might want to overwrite:

LOGGING: 
    DIR: "./dane-server-logs/"
    LEVEL: "DEBUG"
DANE_SERVER:
    TEMP_FOLDER: "/home/DANE/DANE-data/TEMP/"
    OUT_FOLDER: "/home/DANE/DANE-data/OUT/"

Usage

NOTE: DANE-server is still in development, as such authorisation (amongst other featueres) has not yet been added. Use at your own peril.

Run the server component (which listens to the RabbitMQ) as follows:

dane-server

Besides the server component we also need the API, which we can start with:

dane-api

If no errors occur then this should start a webserver (at port 5500) which will handle API requests, while in the background the server will handle interaction with the DB and RabbitMQ.

API

The DANE api is documented with a swagger UI, available at: http://localhost:5500/DANE/

Examples

Examples of how to work with DANE can be found at: https://dane.readthedocs.io/en/latest/examples.html

Docker

To run DANE-server, using Docker make sure to install a Docker Engine, e.g. Docker Desktop for OSX.

Build the Docker images

As the DANE-server has two separate processes. Two images need to be created:

• One for running the Task Scheduler
• One for running the API

Run the following from the main directory of this repo:

docker build -t dane-server -f Dockerfile.ts .
docker build -t dane-server-api -f Dockerfile.api .

Note: currently the build relies on the es-index-cfg branch of DANE (see requirements.txt)

After the images have been successfully built, it is possible to run DANE-server via Kubernetes as well

Kubernetes

These instructions are optimized for minikube, which is for local development only. For deployment to a proper k8s cluster, you're on your own for now...

Note that the provided Kubernetes config only provisions your k8s cluster with:

• Endpoint to external Elasticsearch (make sure you got one running)
• RabbitMQ
• DANE server (task scheduler)
• DANE server API

In order to get a bunch of workers setup, you can check the k8s config files in DANE-asr-worker repository (later on more examples should follow).

Create a configmap for config.yml

First make sure to create the config.yml from the config-k8s.yml:

cp config-k8s.yml config.yml

Now before applying the Kubernetes file dane-server-k8s.yaml to your cluster, first create a ConfigMap for config.yml

kubectl create configmap dane-server-cfg --from-file config.yml

Now the ConfigMap is there, make sure to check that dane-server-k8s.yml points to a existing Elasticsearch host. After that you can go ahead and run:

kubectl apply -f dane-server-k8s.yaml

Configure your local DNS to access the API (and RabbitMQ dashboard)

Check the ip assigned to the dane-server-ingress (and dane-rabbitmq-ingress) by running:

kubectl get ingress

grab the IP from the ADDRESS column and put this in your /etc/hosts file:

{IP}    api.dane.nl rabbitmq.dane.nl

Note: you can assign different domain names by editing the Ingresses in dane-server-k8s.yaml