Data dependencies

[appraveen]

Hello Team,

First of all, thank you for this library. This is really cool.

Most of the times I encounter cases to manage data dependencies between tasks. Though tasks are executed based on it's dependencies, there is no way for a task to read the output from its dependent task. This can be solved by having a global context but it will not make the tasks an independent module. In order to maintain the modularity, it would be great if orchestrator supports providing dependent data for a tasks based on the tasks dependency list.

Example:
A, B, C, D are tasks
C has a data dependency on A & B (ie C is going to use the data that comes from A & B). While executing the task C, orchestrator will send an object that contains output from both A & B

{
"A" : {}, //output from task A
"B" : {} //output from task B
}

There is another orchestrator arch-orchestrator that solves this problem, but it expects a chain

I've created a PULL request #60 to address this issue. Please let me know your thoughts on this PULL & issue.

Thanks,
Praveen