Developing with Python

In the aerospike-graph directory, the python_example.py app demonstrates useful development patterns for connecting to an AGS deployment and adding vertices when building a proof of concept application.

Explore the Python example

With AGS running, let’s test things out using the Python example app.

Set up a Python virtual environment:

python3 -m venv .venv
source .venv/bin/activate

Open the Python example app:
Terminal window
```
open ./python_example/python_example.py
```
Let’s pause for a moment and understand Gremlin syntax. A typical Gremlin command is a chain of traversal steps separated by dots, read from left to right.

It starts with a graph traversal source declaration like:
Terminal window
```
GraphTraversalSource g = traversal().withRemote(conn);

g.V().has('property', 'value').out('edgeLabel').values('anotherProperty')
```
On the second line, you can see our Gremlin command. Let’s break down each step:

g.V() uses the traversal source declared previously as g and then uses V() to start with all vertices.

.has('property', 'value') filters by a property.

.out('edgeLabel') traverses outgoing edges.

.values('anotherProperty') gets property values.

To reiterate, each step processes or filters the graph elements from the previous step.

This will make more sense when looking at a real example. In the example app, lines 15-17 show the following:
python_example.py
```
 g.add_v('foo').\
     property('company', 'aerospike').\
     property('scale', 'unlimited').iterate()
```
g.add_v('foo') adds a vertex labeled "foo" and .property() is used twice to append two properties for this vertex.

The python_example.py begins by importing DriverRemoteConnection and traversal creating a connection with the AGS server. Read through the code comments to understand how Gremlin commands connect to the server, add a vertex, update a property, and delete a vertex.
Install the required packages and run the example.
Terminal window
```
python3 -m pip install gremlinpython async_timeout
python3 ./python_example/python_example.py
```
Example response
Terminal window
Values: ['aerospike', 'unlimited'] Updated: ['aerospike', 'infinite']