manifold.lifecycle — spootnik/maniflow 0.1.4

Convention based lifecycle management of asynchronous chains. This implements a lightweight take on the ideas behind interceptors and similar libraries.

Notable differences are:

• Manifold is the sole provided execution model for chains
• No chain manipulation can occur
• Guards and finalizer for steps are optional
• Exceptions during lifecycle steps stop the execution

run clj

(run init steps)

(run init steps opts)

Run a series of potentially asynchronous steps in sequence on an initial value (init0, threading each step's result to the next step as input.

Steps are maps or the following keys:

[:manifold.lifecycle/id
 :manifold.lifecycle/handler
 :manifold.lifecycle/show-context?
 :manifold.lifecycle/guard]

• id is the unique ID for a step
• handler is the function of the previous result
• context? determines whether the handler is fed the context map or the plain input. When false, the output is considered to be the result, not the context.
• guard is an optional predicate of the current context and previous preventing execution of the step when yielding false

Steps can also be provided as functions or vars, in which case it is assumed that context? is false for the step, and ID is inferred or generated.

In the three-arity version, an extra options maps can be provided, with the following keys:

[:manifold.lifecycle/clock
 :manifold.lifecycle/context?]

• clock is an optional implementation of spootnik.clock/Clock, defaulting to the system's wall clock (spootnik.clock/wall-clock)
• context? toggles extraction of the result out of the context map, defaults to false

step clj

(step id handler & {:keys [context? guard]})

Convenience function to build a step map. Requires and ID and handler, and can be fed additional options