Add example of updating Graph node colors

Would it be possible to update the node colors on Graph?

I’m thinking of making a streamz extension which plots the execution graph and then colors the nodes by if that node is processing data, done processing data, or failed to process the data.

[philippjfr]

Repurposed this issue to add an example demonstrating this in the docs.

[philippjfr]

Is that currently feasible, or does it depend on e.g. #768 ?

That could probably be made to work but note that #768 has very little to do with it. #768 will add the ability to map column values to arbitrary properties on the glyph, but it will not let you switch between glyphs. Since the unicode example uses a completely different glyph (the text glyph) that is not simply some variation on the marker property that PR will not allow you to switch between them arbitrarily without a lot of special handling. Edit: I suppose #768 is general and does cover that, it’s just that the current PR won’t handle that and if we want that behavior it will need special handling.

Ah, so there isn’t a way to say “change the color of that node only” I need to pass in the full node-color mapping every time?

That is correct, DynamicMap callbacks return the whole element each time which will then be translated into an update in the plot. You can of course store the data in one data structure which you keep updating as long as you wrap it in a new Graph.