Garbage collect streams about streamz

[CJ-Wright]

Should we have some logic for this in disconnect as well? Should we have a separate method which searches the graph for references to a node and deletes them?

[mrocklin]

I would implement this by using weakref.Weakset objects. Python would handle this for us automatically

[CJ-Wright]

Ah I see, to properly implement this we would need to have at least one hard reference (which the user needs to keep track of) since all the internal graph references would be weak. I presume that weakref properly propagates the hard reference to one node to all the other nodes?

[mrocklin]

Yes

[mrocklin]

Or rather, I am not currently concerned about if this is possible or how to implement it. I am more curious to know if we want these semantics or not.

[CJ-Wright]

I'm on board with this, although I'm a little curious what happens to the other nodes if we delete the bottom most node.

[jrmlhermitte]

Sorry, I never saw this. I would have disagreed. I would have voted more for a better way to view parents and children and have their references returned.
My main issue is that this will lead to an inconsistency between usage in ipython and running in a script. See #72. I am fine with going through with it, so long as we're all okay with this. We'll have to definitely document this potentially surprising behaviour to a new user. Thanks, and sorry for being late on this.

[CJ-Wright]

I think we should have "a better way to view parents and children and have their references returned" anyway. Especially if we want users to start playing with the pipeline live.

[jrmlhermitte]

I agree. I'm not sure how to make this actionable. Will think about it. Perhaps the stream should have an s.pprint() method? (which would plot a graph like print inline, sort of like git log --graph or simliar?)
We can make it an issue

[CJ-Wright]

I think we could actually return the graph it self (as some sort of DiGraph object) so that people could operate upon the graph (connecting/disconnecting nodes) and have that translated down to the streams level.