I take advantage of I/O being parallel in Python in my mazzle continuous integration pipeline tool. I'm not sharing mutable state.

I spin up a graph of python Threads and each joins others in a graph. This way we can run graphs in parallel. See this graph - the parts that look like this:

dependency -> {parallel1; parallel2; parallel3} -> postparallel

parallel1, parallel2, parallel3 can run in parallel in a separate python thread because the IO is parallel.

postparallel joins parallel1, parallel2, parallel3 and waits for them all to complete.

Where parallel1-3 is things like ansible, packer (slow), AMI builds, chef runs etc.

https://github.com/samsquire/mazzle-starter/blob/master/arch...