I recently was working on a larger ETL process that started with the reception of various data files via SFTP that were delivered on varying schedules. The requirement was that as files are received we generate a unique event in a database, then execute a sequence of commands to archive the files out of the delivery directory and offline to a central immutable annotated file repository.
This new functionality had to integrate with an existing SFTP legacy server, and would likely have other uses outside of this initial use-case.
Looking around for simple solutions based on a scripting language, I really could not find any that would work or be extensible enough for the need. Hence I ended up writing io-event-reactor.
The basic concept is this; you have a monitor that listens for IO events for particular paths on the filesystem. As these IO events occur, they are passed on to one or more evaluators to decide whether or not the IoEvent should be reacted to by one or more configured reactors. The entire latter sequence is encapsulated in an IoReactor instance that manages the flow between the three described components.

#javascript #nodejs #react