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Service scaffolding (nevo-gen)

nevo-gen is a one-shot CLI that produces a working NestJS microservice wired to your chosen transport.

Run

npx nevo-gen <name> [flags]

If @riaskov/nevo-messaging is installed locally, nevo-gen is on the local node_modules/.bin path.

Flags

Flag Default Meaning
-n, --name <name> (positional) Service name (e.g. user, order)
-t, --transport <kind> nats One of nats, kafka, http, socket
-o, --out <path> ./<name> Output directory
-p, --port <number> 8086 Listen port for bootstrap
-f, --force off Overwrite existing files
-h, --help — Print help

Output

For nevo-gen user --transport nats:

user/
├── src/
│   ├── main.ts                 # createNatsMicroservice bootstrap
│   ├── app.module.ts           # imports UserModule
│   └── user/
│       ├── user.module.ts      # ConfigModule + NEVO_NATS_CLIENT provider
│       ├── user.service.ts     # extends NatsClientBase
│       └── user.controller.ts  # @NatsSignalRouter with sample @Signal handlers
├── package.json                # dev/build/start scripts + deps
└── tsconfig.json               # TypeScript 6, ES2024, decorators on

The user.module.ts already includes the right factory (createNevoNatsClient / createNevoKafkaClient / etc.) and DI token.

Try it

npx nevo-gen user --transport nats
cd user
npm install
npm run dev

In another shell:

const u = await client.query("user", "user.getById", { id: 1n })
// → { id: 1n, name: "Sample User" }

Transport notes

NATS

Targets nats://127.0.0.1:4222. Run a broker:

docker run --rm -p 4222:4222 nats:2 -js

Kafka

Expects a broker on localhost:9092. Use the docker-compose snippet in basics-kafka.md.

HTTP

Binds to the given --port. Update app.module.ts to point at your real coordinator URL.

Socket.IO

Starts a Socket.IO server on the given port plus a coordinator URL (replace with yours).

Force overwrite

The CLI refuses to overwrite files by default:

Refusing to overwrite /path/to/user/src/user/user.service.ts (use --force)

Pass --force to replace, or delete the directory first.

After generation

Recommended next steps:

  1. Replace the sample methods with your real domain
  2. Add @Schema() on every public method so the contract has types — see schema.md
  3. Wire up a database in user.module.ts
  4. Add a HealthRegistry — see health-checks.md
  5. Call setupNevoTracing in main.ts — see observability.md

The companion CLI is nevo-contract, which fetches the running contract and generates a TypeScript client — see contracts.md.