There are many methods to communicating between processes. Many methods work best when only using a single programming language, while others require custom packets and parsing.
Simplicity is key and Redis is an efficient solution. Redis is an open-source in-memory database project implementing a distributed, in-memory key-value store.
Sometimes Travis CI builds fail due to sporadic timeouts, network errors, etc. While these non-code errors can be quite annoying, Travis CI has a handy Restart build for when these situations occur, but only users with admin privileges have access to this feature.