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Some abstractions for the gremlin-python module.
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| from gremlin_python.structure.graph import Graph | |
| from gremlin_python.process.graph_traversal import __ | |
| # I use a property instead of directly setting the ID because I could not get it to work, and this works | |
| # just as well for now. I'd imagine setting the id directly is better for runtime. | |
| # If you figure out how to set the id directly with gremlin-python, feel free to make a pull request and I'll merge it. | |
| IDENTIFICATION_PROPERTY = 'identification' | |
| WEIGHT_PROPERTY = 'weight' | |
| """ | |
| Feel free to use this for gremlin-python, which does not have a lot of clear documentation on the differences between | |
| itself and Groovy, even though there are many. | |
| This gist offers some abstracted functions to make starting with gremlin-python easy. | |
| To connect to AWS Neptune with gremlin, you have to use a VPC - you can ssh in your console for example, | |
| but cannot run a script from PyCharm. | |
| See how to connect to AWS Neptune from AWS Lambda, which reduces running database operations to basically running a | |
| PyCharm script, for testing. | |
| https://docs.aws.amazon.com/neptune/latest/userguide/get-started-cfn-lambda.html | |
| """ | |
| def remove_vertex_from_graph(v, g): | |
| """ | |
| remove_node_from_graph | |
| :param v: the vertex to remove | |
| :param g: the graph | |
| :return: - | |
| """ | |
| g.V(v).drop().iterate() | |
| def add_vertex_to_graph(ident, label, g): | |
| """ | |
| add_node_to_graph | |
| :param ident: the id for the new vertex | |
| :param label: the label classifying the vertex | |
| :param g: the graph | |
| :return: - | |
| """ | |
| return g.addV(label).property(IDENTIFICATION_PROPERTY, str(ident)).next() | |
| def remove_edge_from_graph(edge, g): | |
| """ | |
| remove_node_from_graph | |
| :param edge: the edge to remove | |
| :param g: the graph | |
| :return: - | |
| """ | |
| g.E(edge).drop().iterate() | |
| def add_edge_to_graph(v1, v2, label, g): | |
| """ | |
| connect_edges | |
| :param v1: vertex 1 | |
| :param v2: vertex 2 | |
| :param relation: a string label for the edge | |
| :param g: the graph | |
| :return: - | |
| """ | |
| return g.V(v1).addE(label).to(g.V(v2)).next() | |
| def update_edge_weight(edge, increment, g): | |
| """ | |
| update_edge_weight | |
| :param edge: the edge to increment | |
| :param increment: the amount by which to increment the weight | |
| :return: - | |
| """ | |
| g.E(edge).property(WEIGHT_PROPERTY, increment + get_edge_weight(edge, g).next()) | |
| def get_edge_weight(edge, g): | |
| """ | |
| get_edge_weight | |
| :param edge: the edge, of the type returned by get_edge | |
| :return: the weight of the given edge | |
| """ | |
| values = g.E(edge).valueMap().next() | |
| return values.get(WEIGHT_PROPERTY, 0) | |
| def get_edge(v1_id, v2_id, label, g): | |
| """ | |
| get_edge | |
| :param v1_id: the string id of the first vertex | |
| :param v2_id: the string id of the second vertex | |
| :param label: string label of the edge, such as 'knows' | |
| :param g: the graph | |
| :return: the edge | |
| """ | |
| try: | |
| return g.V(v1_id).outE(label).where(__.inV().where(__.hasId(v2_id))).next() | |
| except: | |
| # The edge does not exist. | |
| return None | |
| def get_vertex(ident, label, g): | |
| """ | |
| get_vertex | |
| :param ident: string id of the vertex | |
| :param label: the label of the vertex | |
| :param g: the graph | |
| :return: the vertex | |
| """ | |
| try: | |
| return g.V().hasLabel(label).has(IDENTIFICATION_PROPERTY, ident).next() | |
| except: | |
| # The vertex does not exist | |
| return None | |
| def get_vertices_going_out_from_vertex_with_edge_label(v, g, label=None): | |
| """ | |
| get_vertices_going_out_from_vertex_with_edge_label | |
| :param v: the vertex | |
| :param g: the graph | |
| :param label: optional parameter - if defined, returns all vertices connected to the given vertex via an edge of the | |
| defined label. If not defined, returns all vertices going out from the specified vertex | |
| :return: a list of vertices | |
| """ | |
| if label is None: | |
| # outE gets edges going out | |
| return g.V(v).out().fold().next() | |
| else: | |
| return g.V(v).out(label).fold().next() | |
| def get_vertices_going_in_to_vertex_with_edge_label(v, g, label=None): | |
| """ | |
| get_vertices_going_in_to_vertex_with_edge_label | |
| :param v: the vertex | |
| :param g: the graph | |
| :param label: optional parameter - if defined, returns all vertices connected to the given vertex via an edge of the | |
| defined label. If not defined, returns all vertices going out from the specified vertex | |
| :return: a list of vertices | |
| """ | |
| if label is None: | |
| # inE gets edges going in | |
| return g.V(v).in_().fold().next() | |
| else: | |
| return g.V(v).in_(label).fold().next() | |
| def get_label_counts(g): | |
| """ | |
| get_label_counts | |
| :param g: the graph | |
| :return: a dictionary mapping string labels to integer counts | |
| """ | |
| return g.V().label().groupCount().next() | |
| def get_edges_with_label(label, g): | |
| """ | |
| get_edges_with_label | |
| :param label: a string label | |
| :return: a list of edges with the label considered | |
| """ | |
| return g.V().out(label).fold().next() | |
| def get_vertices(g, label=None): | |
| """ | |
| get_vertices | |
| :param g: the graph | |
| :param label: optional parameter; the label type of the vertices considered | |
| :return: a list of vertices | |
| """ | |
| if label is None: | |
| return g.V().fold().next() | |
| else: | |
| return g.V(label).fold().next() |
Author
Newbee to Gremlin, I see line g = graph.traversal().withRemote(DriverRemoteConnection('ws://localhost:8182/gremlin','try1')) is not working with latest gremlinpython module, it works only on version gremlinpython==3.3.2, Any suggestion are welcome.
Hi Sandoshv,
I don't see the line you referenced in this gist - could you please clarify?
Josh
I am sorry for the confusion. You are awesome. Above sample works great with gremlinpython==3.3.2, but on latest gremlinpython 3.4.3, I am facing syntax deprecated warnings on my below connection lines(which is not present in this sample provided)
g = graph.traversal().withRemote(DriverRemoteConnection('ws://localhost:8182/gremlin','try1'))
Author
Ah gotcha! I am not sure why that is the case, primarily because I don't know too much Gremlin, but I recommend joining this Google Group (see link below) and asking the question there. There are some real pros on there that can help you out.
https://groups.google.com/forum/#!forum/gremlin-users
I am sorry for the confusion. You are awesome. Above sample works great with gremlinpython==3.3.2, but on latest gremlinpython 3.4.3, I am facing syntax deprecated warnings on my below connection lines(which is not present in this sample provided)
g = graph.traversal().withRemote(DriverRemoteConnection('ws://localhost:8182/gremlin','try1'))
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Newbee to Gremlin, I see line g = graph.traversal().withRemote(DriverRemoteConnection('ws://localhost:8182/gremlin','try1')) is not working with latest gremlinpython module, it works only on version gremlinpython==3.3.2, Any suggestion are welcome.