csdsclient: add visualization

[Rainton]

This PR includes adding flag -visualization to show the relationship between xDS in the config in response.

Details:

• Added flag -visualization and added support to it

• Solved conflicts between -visualization and -monitor_interval

• Added test for visualization

Signed-off-by: Yutong Li yutongli@google.com /cc @fuqianggao @alexburnos

[Rainton]

/cc @htuch @dschaller

[fuqianggao]

/cc @dio @therealmitchconnors

[therealmitchconnors]

I really like this feature. I'm a little unclear on the details though. What questions is the visualization intended to solve? Can you describe the rules used to build the graphviz markup? Does color represent sync status? perhaps a key section would be useful...

[Rainton]

@therealmitchconnors Sorry for my unclear expression.

The detailed config in response is always so long that users cannot figure out the relationships between each xDS easily. The visualization feature is used to give users a clear view of the relationships by going through the detailed config, storing relationships between xDS in maps, drawing a graph by marking xDS as nodes and relationships as edges. Different colors represent different xDS types, such as LDS, RDS, CDS, and EDS.

Maybe you can take a look at this sample graph to get clearer to what this feature would be like.

The user scenario may be like this: the user sees the graph and finds that there are two RDSs here and both of them are related to the CDS0. If the user want to see the detailed config of one of the RDS, he can just hovers the mouse over the specific RDS node and its real name will shows. Then the user can find the config of this RDS easily by searching this real name in the detailed config.

[dio]

Seems like you need to merge master.

[Rainton]

@dio Sorry about that. I've just merged.