gremlinpython writing a helper function to create vertexes if they don't exist, and create an edge between them if it doesn't exist

Question

I'm working with gremlin and gremlinpython for the first time, and I'm hitting a wall when I try to create new vertexes and an edge between them. I've looked at some of the other resources online, but I'm kind of reaching my wits end. Here is what I have so far.

def merge_vertexes_and_edge(g, name1:str, name2:str, src: int, dest: int):
    g.V().has('name', name1).fold().coalesce(
        unfold(),
        addV('node').property('id', str(src)).property('name', name1)
    ).as_('v1').V().has('name', name2).fold().coalesce(
        unfold(),
        addV('node').property('id', str(dest)).property('name', name2)
    ).as_('v2').V('v1').out('knows').has('name', name2).fold().coalesce(
        unfold(),
        addE('knows').from_('v1').to('v2').property('name', f"{src}-{dest}")
    ).iterate()
    ```

Answer 1

I created two helper functions, that for now, do well enough.

# Helper function to create an edge between two vertices if it doesn't exist
def create_edge(g, src: int, dest: int):
    # Get the vertices by their ids
    v1 = g.V().has('id', src).next()
    v2 = g.V().has('id', dest).next()

    # Check if an edge between v1 and v2 already exists by name
    edge_exists = g.V(v1).out('knows').has('name', f"{src}-{dest}").hasNext()

    if not edge_exists:
        # Edge doesn't exist, so add it
        g.V(v1).as_('v1').V(v2).addE('knows').to('v1').property('name', f"{src}-{dest}").iterate()


# Helper function to create a vertex if it doesn't exist
def create_vertex(g, id: int, name: str):
    # Check if a vertex with the given name already exists
    vertex_exists = g.V().has('name', name).hasNext()
    
    if not vertex_exists:
        # Vertex doesn't exist, so add it
        g.addV('node').property('id', str(id)).property('name', name).iterate()