Jsonnet-as-a-Service

Jsonnet-as-a-Service (JaaS) evaluates Jsonnet and returns JSON. It runs in one of two modes:

• OCI volume mounting — the chart mounts your snippets and libraries from OCI artifacts as image volumes, and JaaS serves the evaluated JSON over HTTP (GET /jsonnet/<snippet>). Static content, no custom resources.
• Flux CR-based — JaaS watches JsonnetSnippet and JsonnetLibrary resources and publishes the rendered output as a Flux ExternalArtifact that any Flux consumer deploys.

The two modes are mutually exclusive in one chart release; Installation covers choosing one.

What teams build with it

• Grafana dashboards with grafana-operator. Author dashboards in Jsonnet (grafonnet), let JaaS render them, and have the grafana-operator reconcile the result into Grafana. See Grafana dashboards .
• Kubernetes manifests with stageset-controller. Render manifests from Jsonnet and roll them out in ordered, gated stages with stageset-controller . See Deploying manifests with StageSet .

Both build on the same core: a snippet renders to an ExternalArtifact, and a downstream controller consumes it. JaaS only renders — what happens to the JSON is the consumer’s concern, documented on that consumer’s own site.

Where to start

• Get started — render locally with no cluster, or install JaaS on Kubernetes and call its Quickstart endpoint.
• Rendering Jsonnet — the HTTP renderer: snippets, libraries, external variables, and the limits around evaluation.
• Operator mode — evaluate JsonnetSnippet resources and publish each result as a Flux ExternalArtifact.
• Guides — Grafana dashboards, and deploying rendered manifests with StageSet.
• API reference — every field of JsonnetSnippet, JsonnetLibrary, and the ExternalArtifact output contract.
• Runbooks — symptom, cause, and remediation for every Ready-condition reason.

Project

• Source, releases, and the container image: github.com/metio/jaas
• Helm chart: oci://ghcr.io/metio/helm-charts/jaas