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Using the Python API

This section covers an overview of the python API extension for Gaffer to demonstrate how to get up and running to perform queries from Python code on an existing running graph.

Tip

Please see the handy introduction to Python if you are new to the language.

What is the Python Extension?

Commonly referred to as gafferpy this is an API to gaffer that provides similar querying capabilities to the rest API but from Python. Fundamentally it wraps the rest API to use the same JSON under the hood this means you should be able to access almost any features or end points available in the main rest API.

Installation

Currently there isn't a release of gafferpy on pypi or other pip repository; however, the source code can still be cloned from the git repository and installed via pip. Please see the readme in the gafferpy repository for full instructions.

How to Query a Graph

To get started with gafferpy you will need to import the module and connect to an existing graph, the connection should be the same address as where the rest API is running.

from gafferpy import gaffer
from gafferpy import gaffer_connector
g_connector = gaffer_connector.GafferConnector("http://localhost:8080/rest/latest")

Once connected you can access and run the same endpoints and operations as you would via the usual rest API but via their python classes. The endpoints are accessed via the GafferConnector to allow you executing Operation chains to perform queries on the graph.

Note

Some of the features of the full rest API may not be present in gafferpy so always check the reference guide first.

A simple Operation can be called via the execute_operation() function. As an example, the following will get all the elements in a graph:

elements = g_connector.execute_operation(
    operation =  gaffer.GetAllElements()
)

An Operation chain can be run using the execute_operation_chain() function. As an example, the following will get all the elements in a graph then count them.

count = g_connector.execute_operation_chain(
    operation_chain = gaffer.OperationChain(
        operations=[
            gaffer.GetAllElements(),
            gaffer.Count()
        ]
    )
)

Along with running Operations you can of course optionally apply some filtering using a View. There is more detail on both filtering and operations on their respective pages.

Last update: October 16, 2023
Created: September 21, 2023