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Secret sauce code now open source ( * it beats AI generated code)

TDK CLI: How a Simple service.json Becomes a Full Local Stack

Most multi-service setups still force you to maintain Docker Compose files, Tiltfiles, nginx configs, port maps, and health checks by hand. AI coding agents make the application code easy, but they are still bad at keeping the local infrastructure consistent.

TDK CLI solves this by treating a tiny declarative file as the source of truth and generating everything else.

The Contract

This is essentially all you write for a service:

{
  "$schema": "https://tdk-landscape.github.io/schema.service.json",
  "schemaVersion": 1,
  "appName": "orders-api",
  "appType": "backend",
  "stack": "shop",
  "port": 4000,
  "healthCheckPath": "/health",
  "dependsOn": []
}
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From this single file, TDK generates Dockerfiles, live-reload rules, Traefik routes, shared Postgres wiring, health probes, and the Tilt configuration that actually runs it.

The project is organized as Project → Stack → Resource.

flowchart LR
    P[Project<br/>.tdk/project.json] --> S1[Stack: shop]
    P --> S2[Stack: billing]
    S1 --> R1[orders-api<br/>backend]
    S1 --> R2[orders-app<br/>frontend]
    S2 --> R3[checkout-api<br/>backend]

Three Subsystems

The codebase is deliberately split so each part has a clear job:

flowchart TB
    subgraph CLI["cli/ (TypeScript)"]
        Commands[Commands & validation]
        Templates[Handlebars templates]
        Ports[Port allocation]
    end

    subgraph Discovery["discovery/ (Starlark)"]
        Scan[Scan service.json]
        DAG[Build dependency DAG]
    end

    subgraph Engine["engine/ (Starlark)"]
        LiveUpdate[live_update rules]
        Traefik[Traefik routing]
        Infra[Postgres + platform]
    end

    CLI -->|generates Tiltfile + configs| Discovery
    Discovery -->|registry + DAG| Engine
    Engine -->|docker_build + containers| Docker[(Docker)]
Subsystem Language Responsibility
cli/ TypeScript Commands, validation, port allocation, template generation, launching Tilt
discovery/ Starlark Scan for service.json files, normalize them, build the dependency DAG
engine/ Starlark Runs inside Tilt — turns the DAG into real docker_build, live_update, Traefik, Postgres, etc.

The CLI never starts containers itself. The engine never parses CLI flags. Discovery never builds images.

The Generation Step

The real glue is the template engine (cli/src/generator/template-engine.ts). It reads .tdk/project.json and emits files into the gitignored .tdk/.tdk-out/ directory:

  • Tiltfile
  • TILT_TECH_STACK.star and TILT_RESOURCE_DEFAULTS.star
  • spec.master
  • .tiltignore

These come from Handlebars templates. The CLI also vendors a copy of the engine and discovery code so tdk up works offline.

What Happens When You Run tdk up

sequenceDiagram
    actor Dev
    participant CLI as TDK CLI
    participant Gen as Template Engine
    participant Tilt
    participant Engine as Starlark Engine
    participant Docker

    Dev->>CLI: tdk up shop
    CLI->>CLI: Preflight (Docker, schema, drift, ports)
    CLI->>Gen: Ensure master configs
    Gen-->>CLI: .tdk/.tdk-out/Tiltfile
    CLI->>Tilt: tilt up -f Tiltfile -- --focus=shop
    Tilt->>Engine: Load discovery + engine
    Engine->>Engine: Scan service.json → DAG
    Engine->>Docker: docker_build + live_update
    Engine->>Docker: Start Traefik + Postgres
    Docker-->>Tilt: Containers healthy
    Tilt-->>CLI: Ready
    CLI-->>Dev: Print URLs + Tilt UI

High-level steps:

  1. Find the project root and run preflight checks.
  2. Plan host ports (prefer 80/443/5432, fall back if busy).
  3. Ensure master configs exist (regenerate if needed).
  4. Auto-enable newly discovered stacks into the pre_alpha phase.
  5. Spawn tilt up against the generated Tiltfile.
  6. Inside Tilt the engine generates per-service .autogenerated/ files, registers builds with live-update, and starts shared infrastructure.
  7. The CLI waits for readiness and prints the real URLs.

Committed vs Generated

TDK is strict about this boundary so AI agents (and humans) cannot silently break the infrastructure:

flowchart LR
    subgraph Committed["Committed (source of truth)"]
        PJ[.tdk/project.json]
        SJ[services/*/*/service.json]
        Code[Your app source]
    end

    subgraph Generated["Generated (gitignored)"]
        Out[.tdk/.tdk-out/<br/>Tiltfile, specs]
        Auto[services/*/*/.autogenerated/]
        Env[.env]
    end

    Committed -->|tdk project / tdk resource / tdk up| Generated
    Generated -->|tdk config regenerate| Committed
Path Status Why
.tdk/project.json Committed Project identity and phases
services/*/*/service.json Committed Service contract
Application source Committed Your code
.tdk/.tdk-out/ Generated Derived from templates
services/*/*/.autogenerated/ Generated Engine output during Tilt
.env Generated Local secrets

What It Is Not

TDK is a local development runtime. It does not deploy to staging or production. The project explicitly leaves production to Helm, Argo CD, or whatever you already use. The local environment is optimized for speed and developer experience, not for being a perfect replica of production.

Getting Started

npm install -g @tdk-landscape/tdk-cli-core
tdk doctor
tdk project --yes
tdk resource orders-api --type backend --stack shop --yes
tdk up shop
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Or clone the official starter and open it in any cloud IDE.

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cool!

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