define

workflow.define: typed entry contract (entry fn + input/output/error codecs)

Types

WorkflowDefinition

opaque </>

A typed workflow entry contract for the Aion engine.

Workflow authors write a plain function fn(input) -> Result(output, error) and expose it to the engine by returning a WorkflowDefinition from the package entry function named in the .aion manifest. AE consumes this value at spawn: it calls that named package entry function, receives the definition, decodes the input Payload with input_codec, invokes/drives the typed entry function, and encodes the output or error Payload with output_codec or error_codec.

AP (aion-package) records only the entry module and function names as strings in the manifest; it does not introspect this Gleam value. The SDK carries the contract but does not invoke entry_fn itself.

pub opaque type WorkflowDefinition(input, output, error)

Values

define

</>

pub fn define(
  name: String,
  input_codec: codec.Codec(input),
  output_codec: codec.Codec(output),
  error_codec: codec.Codec(error),
  entry_fn: fn(input) -> Result(output, error),
) -> WorkflowDefinition(input, output, error)

Define a typed workflow entry contract consumed by AE at spawn.

entry_fn

</>

pub fn entry_fn(
  definition: WorkflowDefinition(input, output, error),
) -> fn(input) -> Result(output, error)

Return the typed entry function carried for AE to invoke/drive.

error_codec

</>

pub fn error_codec(
  definition: WorkflowDefinition(input, output, error),
) -> codec.Codec(error)

Return the error codec used by AE to encode failed completion Payloads.

input_codec

</>

pub fn input_codec(
  definition: WorkflowDefinition(input, output, error),
) -> codec.Codec(input)

Return the input codec used by AE to decode the spawn Payload.

name

</>

pub fn name(
  definition: WorkflowDefinition(input, output, error),
) -> String

Return the workflow name carried by the definition.

output_codec

</>

pub fn output_codec(
  definition: WorkflowDefinition(input, output, error),
) -> codec.Codec(output)

Return the output codec used by AE to encode successful completion Payloads.