Getting Started - Python

How to use Python to create a DocumentProcessor.

Requirements

• Python 3.7+

Installing mtap

To install mtap run the following:

pip install mtap

Creating a processor

We will be creating a document processor which simply writes a hello world label to a document.

To start, create a file named hello.py, this file will contain our processor:

from mtap import DocumentProcessor, run_processor


class HelloProcessor(DocumentProcessor):
    def process_document(self, document, params):
        with document.get_labeler('hello') as add_hello:
            text = document.text
            add_hello(0, len(text), response='Hello ' + text + '!')


if __name__ == '__main__':
    run_processor(HelloProcessor())

This file receives a request to process a document, and then labels that document’s text with a hello response.

Running the processor

To host the processor, run the following commands in terminal windows.

python -m mtap events -p 9090 &
python hello.py -p 9091 -e localhost:9090 &

To perform processing, create another file pipeline.py:

import sys

if __name__ == '__main__':
    from mtap import Document, Event, Pipeline, events_client
    from mtap import RemoteProcessor

    pipeline = Pipeline(
        RemoteProcessor(processor_name='helloprocessor', address=sys.argv[2]),
    )
    with events_client(sys.argv[1]) as client:
        with Event(event_id='1', client=client) as event:
            document = Document(document_name='name', text='YOUR NAME')
            event.add_document(document)
            pipeline.run(document)
            index = document.labels['hello']
            for label in index:
                print(label.response)

To run this pipeline type

python pipeline.py localhost:9090 localhost:9091

Interacting with the Events Service

When you deploy the processor above, the MTAP framework hosts the processor as a gRPC service that can be contacted to process documents. When it receives a request, it uses the request parameters to instantiate the Document object that gets passed to your processor. This Document object is your interface to the events service.

For more information about the methods that are available, see the API Documentation.

Cleaning up

When you launched the events service and the processor above in the background it should have gave you a job number and pid (process id) [<job_no>] <pid>. Example:

$ python -m mtap events -p 9090 &
[1] 75106
$ python hello.py -p 9091 -e localhost:9090 &
[2] 75214

You can close those background jobs like this:

kill %1 %2