Typed Configuration on Nickel

Your configuration has outgrown plain YAML and template JSON. Duplicated blocks, subtle typos, and environments that gradually diverge result in downtime and lengthy reviews. I describe configuration as real typed code in Nickel — a language from Tweag — and generate the JSON or YAML that your tools already understand.

What you get:

— A Nickel codebase where environments (dev, staging, production) are described as composable records: shared default values merge with environment-specific overrides instead of copy-paste.
— Contracts that validate every value before rendering: enumerations of regions and instance types, bounds for replicas and timeouts, mandatory fields, correct hosts and ports. A faulty config fails at build time with a clear message, not at night in production.
— Reusable functions and library modules: typical entities (service, deploy, ingress) are described once and parameterized.
— Export pipelines that deliver clean JSON or YAML for Kubernetes, Terraform, Nomad, systemd, GitHub Actions, and any tool reading structured configs.
— A migration path from existing Jsonnet, Dhall, Helm-values, or manual YAML, with a diff proving the generated output matches what works for you now.
— Tests, a target for Makefile or justfile, and documentation so your team can extend the schema without me.

I also integrate Nickel into CI: every merge request automatically passes type and contract checks. Describe your current schema and target format — and I'll estimate the task precisely.