Pipelines with error handling in Clojure

Question

I'm looking for a smart way to create composable validation and transformation pipelines in Clojure. The aim is to be able to do simple translation and validation of messages using composable steps.

Main requirements:

• Can be composed functionally, i.e. pipelines are pure functions
• Can be applied to regular Clojure data types (maps, vectors, lists, and nested combinations thereof)
• Can perform transformations, e.g. renaming a key in map
• Can perform arbitrary validations (e.g. applying a Schema validation to part of a message)
• Can bail out gracefully when errors are detected, and return a meaningful error message (not just throwing an exception!)

I guess I can write all this, but don't particularly feel like reinventing the wheel today :-)

Dopes anyone know of a tool that can do this, or have a good idea regarding how to construct one in a clever and general way?

Answer 1

You might find Promenade (see documentation), a library I have been working on for elegant error handling and control flow, useful for some of the things described in the question.

Answer 2

You might look at Zach Tellman's Lamina library. You can create pipelines of functions with error handlers as other useful functionality.