Module codegen 

Gleam type and JSON codec generation from project schemas. Gleam type + JSON codec generation from a workflow project’s JSON Schemas (aion codegen).

codegen_project reads a project’s workflow.toml and every schemas/*.json, and writes one deterministic Gleam module (src/<package>_io.gleam) containing a type plus an encoder/decoder pair per schema — the schema files stay the single source of truth, and the generated codecs cannot drift from them. CodegenMode::Check verifies the on-disk module instead of writing, for CI gates. The library never spawns processes; everything observable is in the returned CodegenReport or CodegenError.

Structs

ActivityArtifact

One generated file: its path and fully-rendered contents.

ActivityDeclaration

A validated activity declaration: the per-activity facts the generator needs.

ActivityReport

The result of generating (or checking) a package’s activity plumbing.

CodecReport

The result of generating (or checking) a package’s codecs module.

CodegenReport

Result of a successful codegen run.

TestScaffoldReport

The result of generating (or checking) a workflow’s aion/testing skeleton.

Enums

CodegenError

Errors produced while generating Gleam types and codecs from a workflow project’s JSON Schemas.

CodegenMode

What to do with the generated module.

Tier

Where an activity’s side-effecting body executes.

Functions

build_input_skeleton

Builds a structurally-valid input skeleton from a workflow input_schema JSON-Schema document.

codegen_project

Generates Gleam types and JSON codecs for every schemas/*.json of the workflow project at root, writing or checking src/<package>_io.gleam per mode.

generate_activities

Generates (or, in CodegenMode::Check, verifies) the activity plumbing for the package at root from its declarations and schemas/*.json.

generate_codecs

Generates (or, in CodegenMode::Check, verifies) the package’s codecs module src/<package>_codecs.gleam from its schemas/*.json.

generate_test_scaffold

Generates (or, in CodegenMode::Check, verifies) the aion/testing skeleton test/<entry_module>_scaffold_test.gleam for the workflow whose typed entry lives in src/<entry_module>.gleam.

parse_declarations

Parses and validates the canonical activity-manifest JSON.