Explain why a unified config has a given value
Trace one field of a config unified from base, team, and environment files back to the line that set it, and fail CI when a field still rests on a default.
How-to › Section 16
Model, configure and generate#
Spec languages for configuration, environment overlays, application models that generate artifacts, project generators, and templates that produce deterministic code.
10 guides in 5 topics. Every guide compares its approaches and shows the output its commands printed.
- Unify configuration with a spec language 3
- Layer configuration across environments 1
- Model an application and generate from it 1
- Generate code and projects 2
- Engineer templates and AST transforms 3
Unify configuration with a spec language 3 guides
Configuration as a lattice: aontu (unification, types, defaults such as *8080 | integer, references, conjunction and disjunction, reading a contradiction error, the verbs vet, get, why, set, subsume, breaking, trim, relations, hash, mod, reaches, jsonschema; the LSP and the stdio MCP server) against CUE, Jsonnet, Dhall, Pkl, KCL and Nickel.
Let a coding agent edit a config spec without breaking it
Run counterexamples the spec must refuse beside vet, after every agent edit and at commit, so an agent that deletes a constraint to clear an error is stopped there.
Reference one value from many places in a config spec
Name a service once and build its host name, log prefix, and queue name from it in CUE, Dhall, Jsonnet, and Nickel, then see which references survive a refactor.
Layer configuration across environments 1 guide
Configuration as data: Kustomize overlays, Helm values, YAML anchors, Jsonnet, Dhall, Pkl, KCL and CUE for environment layering; validating manifests in CI, removing duplication, migrating between languages, keeping secrets out of config, and when a unification language earns its keep.
Diff rendered manifests per environment before you merge
Render each overlay from a pull request and from its base, diff every environment with dyff, and post the result as one comment before anything merges.
Model an application and generate from it 1 guide
One model for entities, services, messages, fields and environments, then generating artifacts from it: @voxgig/model (unify .aon files into one model.json, actions that generate artifacts, --watch), model-react and model-vue bindings, and the early-stage apigen and udk projects.
Rebuild artifacts on model change with a watch loop
Regenerate TypeScript types and SQL within a second of a model edit, keep the last good output when a generator fails partway, and make the watch loop log why.
Generate code and projects 2 guides
Scaffolding and repeatable generation: jostraca (component tree of Project, Folder, File, Content, Fragment, Slot, Inject, Copy; define then build; in-memory generation for tests; byte-identical TypeScript and Go implementations; inks interpolation) against Yeoman, Plop, Hygen, Cookiecutter, Copier, Nx generators, Projen and Rails generators; plus pushing one template change to hundreds of repositories (repo-manager, the gh CLI, the Terraform GitHub provider, Renovate presets).
Push one CI template change to five hundred repositories
Fan one workflow change out over hundreds of repositories with a dry run, a checkpoint and three known end states, against four ways to stop copying the file.
Scaffold a Python API client project with Cookiecutter
Turn a Python client layout into a Cookiecutter template with derived names, a hook that survives a second run, and a test that bakes it into a temporary directory.
Engineer templates and AST transforms 3 guides
Deterministic generated code: EJS, Handlebars, Mustache, Jinja and Go templates; AST-based generation with ts-morph, jscodeshift and go/ast; codemods across generated files; formatting after generation; golden-file and snapshot tests of generated output; stable ordering and no timestamps.
Format generated code as the last step of generation
Format generated TypeScript, Go, and Python in memory with the consuming project's settings, before the generator writes, so no run needs a formatting commit.
Make a Handlebars template produce byte-identical output
Sort the model, keep helpers pure, normalise line endings and compile strict, so a Handlebars template renders the same bytes everywhere, checked with sha256sum.
Run a codemod across every generated file with jscodeshift
Rename a method across a directory of generated TypeScript with a jscodeshift transform, prove a second run changes nothing, then move the change into the template.
Generate the client instead of writing it#
Retries, timeouts, pagination and auth are the same problems in every client. Voxgig generates them from your OpenAPI description, in 23 languages, from one model.