How to generate graph diagrams like those included in documentation?

[trickmeyer]

How can I generate images like the link below without writing the graphviz, etc. myself?

https://pythonhosted.org/graphkit/_images/example_graph.svg

[ankostis]

graph = compose(...)
graph.net.plot("workflow.png")

You may use one of those file extensions: .png .dot .jpg .jpeg .pdf .svg

Alternatively you may open a matplotlib window:

graph.net.plot(show=True)

[ankostis]

There is a much more direct way, edited on my original reply.

[andres-fr]

@ankostis Thanks for your answer! This more direct way triggers an exception in my case, due to the output stream expecting a string and getting a binary.

My fix was to set the output file mode to "wb" (permalink):

graphkit/graphkit/network.py

Line 426 in e70718b

with open(filename, "w") as fh:

As a workaround, your prior suggestion works like a charm (png, svg...):

with open("/tmp/test.svg", 'wb') as f:
    f.write(graph.net.plot().create_svg())

Note that this requires pydot

[ankostis]

thanks. Will update my PR 👍

[andres-fr]

The existing function was also creating the file in cases where the extension isn't supported. I think that it is better to match the extension first, and open the file after, something like this works for me:

def plot_graph(g, out_path: str) -> None:
    """
    :param g: A ``graphkit`` graph as the ones output by the
      ``graphkit.compose`` function
    :param out_path: The absolute output path with extension. Supported
      extensions: ``[png, dot, jpg, jpeg, pdf, svg]``.

    Plots the computational graph using ``graphviz``. For that requires
    ``pydot`` to be installed.

    .. note::

      This definition is almost identical to the built-in one, but it uses
      ``wb`` mode instead of ``w`` to avoid exception. For more details see:
      https://github.com/yahoo/graphkit/issues/13#issuecomment-536342255
    """
    basename, ext = os.path.splitext(out_path)
    plt = g.net.plot()
    # check if extension is known
    if ext.lower() == ".png":
        obj = plt.create_png()
    elif ext.lower() == ".dot":
        obj = plt.to_string()
    elif ext.lower() in [".jpg", ".jpeg"]:
        obj = plt.create_jpeg()
    elif ext.lower() == ".pdf":
        obj = plt.create_pdf()
    elif ext.lower() == ".svg":
        obj = plt.create_svg()
    else:
        raise Exception("Unknown file format for saving graph: %s" % ext)
    # if extension matched, save created object
    with open(out_path, "wb") as f:
        f.write(obj)

Would PR myself but seems that I need credentials? In any case, this is my code, feel free to adapt at will.
Cheers!
Andres

[ankostis]

Would PR myself but seems that I need credentials?

For this project specifically? You just need to sign an (automated) CLA, that you mean?

[andres-fr]

Yes, I will look into that for the next time. In any case I see that you are working on that and it probably would be a bad idea to interfer. Thanks for your effort!

[ankostis]

Thank you for the guidance.

Btw, are you related to this project?
Do you know if it's alive?