Define and use custom step in Gremlin via pyorient.

custom_gremlin_step_pyorient.py

#!/usr/bin/env python

"""
Define and use custom step in Gremlin via pyorient.
"""

from pyorient.ogm import Graph, Config
from pyorient.ogm.declarative import declarative_node, declarative_relationship
from pyorient.ogm.property import String

Node = declarative_node()
Rel = declarative_relationship()

class TestNode(Node):
    element_type = 'testnode'
    element_plural = 'testnodes'
    mystr = String(nullable=False, unique=False, indexed=True)

class TestRel(Rel):
    label = 'testrel'

if __name__ == '__main__':
    g = Graph(Config('localhost', 2424, 'admin', 'admin', 'ogm',
                     storage='memory', initial_drop=True))
    g.create_all(Node.registry)
    g.create_all(Rel.registry)

    foo = g.testnodes.create(mystr='foo')
    bar = g.testnodes.create(mystr='bar')
    baz = g.testnodes.create(mystr='baz')

    g.testrel.create(foo, bar)
    g.testrel.create(bar, baz)
    g.testrel.create(baz, foo)
    
    g.client.gremlin("Gremlin.defineStep('mystep', [Vertex, Pipe], {_().out.out});")
    result = g.gremlin("g.V.has('mystr', 'foo').mystep")
    assert result[0].mystr == 'baz'
    result = g.gremlin("g.V.has('mystr', 'bar').mystep")
    assert result[0].mystr == 'foo'