Task Group: Node order changes after collapse

[JCoder01]

Apache Airflow version: 2.0.0rc1

Kubernetes version (if you are using kubernetes) (use kubectl version):

Environment:

• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

What happened:

The order of the nodes changes when expanding and collapsing task groups:
Before:

After expanding task group and collapsing:

What you expected to happen:
node order to be consistent
How to reproduce it:

Create a DAG with multiple task groups.
expand the top group
collapse the top group
observe is is now at the end.

Anything else we need to know:

happens every time.

[turbaszek]

CC @yuqian90

[turbaszek]

Thanks @JCoder01, as I understand this is not a "real bug" but just an unpleasant UX, right?

[JCoder01]

@turbaszek Yeah, there is nothing wrong with the functionality. It's just a tad annoying when things move around.

[yuqian90]

@turbaszek Yeah, there is nothing wrong with the functionality. It's just a tad annoying when things move around.

In fact, this isn't an issue for TaskGroup specifically. Even before TaskGroup was introduced, simply refreshing the page can sometimes render the Graph View differently causing the nodes to shuffle around.

I can understand the pain. However, this issue needs to be addressed in the dependent package Dagre. I think this is the open issue upstream: dagrejs/dagre#189

Unfortunately it doesn't look like they are addressing it any time soon. Hopefully someone can come up with a workaround.

[ashb]

Could some test this on Rc3 -- I don't see it there.

If you do see it, please give me a reproduction test case.

[JCoder01]

@ashb Just installed RC3 and see the same. The behavior is evident on that example_task_group dag.
Before

After

[ashb]

I wonder if I don't see it cos I use Firefox

[JCoder01]

I don't know, I tried Firefox on both windows and linux and the same thing happens.

[eladkal]

I was able to reproduce using the example_task_group DAG :

[kaxil]

@bbovenzi Can you take a look at this one when you have time please

[bbovenzi]

dagre still has not been updated. If someone wants to fork that library or add logic to remember the order, feel free to open a PR. But I will not be focusing on this as we will use a different graphing library in AIP-38.

[yuqian90]

Hi @bbovenzi , just curious, what graphing library are we switching to in AIP-38? I think it makes sense to start thinking about how to implement Graph View and Tree View using that new library.

[bbovenzi]

@yuqian90 I'm still looking into it, so I'm open to suggestions. We can certainly bring those updates into the current UI when it's well tested.

[bbovenzi]

Just tested again in the new graph view. Group children appear to maintain their order.