NCPS Developer Skill

This skill documents the standard workflows for developing, building, running, and testing the ncps project.

🔴🟢🔵 Development Protocol: TDD ONLY

[!IMPORTANT] TEST FIRST. CODE SECOND. You MUST follow Test Driven Development (TDD) for ALL Go code changes, including FEATURES and BUGS.

The Cycle:

• Red: Write a failing test case that reproduces the bug or defines the new feature.

• Green: Write the minimal amount of code necessary to make the test pass.

• Refactor: Clean up the code while ensuring tests remain green.

Do not write implementation code without a failing test.

Environment Setup

The project uses Nix to manage dependencies. Ensure you have Nix installed.

Start Services: Before running the application or tests that require backing services (Postgres, MySQL, Redis, MinIO), start them using:

nix run .#deps

This command starts a process manager (process-compose) that runs all necessary services in the foreground. Keep this running in a separate terminal.

Run DevShell Tools: When using Claude Code, run any devShell tool (go, golangci-lint, sqlc, dbmate, sqlfluff) with nix develop --command :

nix develop --command go test ./... nix develop --command golangci-lint run --fix nix develop --command sqlc generate

This works consistently in both the main working tree and in worktrees. For interactive use, you can also use nix develop or direnv allow if you have direnv installed.

Enable Service Connectivity: To export the environment variables required to connect to the backing services (especially for running go test ), you must source the configuration:

eval "$(enable-integration-tests)"

You can also enable specific services individually (e.g., eval "$(enable-postgres-tests)" ).

Running the Application

The primary way to run ncps locally during development is via dev-scripts/run.py .

Basic Usage

./dev-scripts/run.py [flags]

Common Flags

• --mode : single (default) or ha (High Availability).

• --db : sqlite (default), postgres , or mysql .

• --storage : local (default) or s3 .

• --locker : local (default) or redis .

• --instances : Number of instances for HA mode (default: 3).

Examples

Run single instance with SQLite (default):

./dev-scripts/run.py

Run HA cluster with Postgres and S3:

./dev-scripts/run.py --mode ha --db postgres --storage s3 --locker redis

[!NOTE] The script automatically handles database migrations using dbmate before starting the application.

Testing

Unit Tests

Run standard Go tests:

go test ./...

Database Tests

The project has extensive database tests in pkg/database . These require the backing services to be running (see "Environment Setup").

Kubernetes Deployment Tests

To test Kubernetes deployments (requires a cluster):

./dev-scripts/test-deployments.py --config dev-scripts/test-deployments-config.yaml

Database Management

Migrations are managed via dbmate . See the dbmate skill for general usage, but note that dev-scripts/run.py handles applying migrations automatically for development.

To create a new migration for all supported engines, use the workflow:

/migrate-new "migration_name"