Engineering Guidelines

This document defines how applications in SKIC Playground are structured, built, and maintained.

Monorepo Structure

All applications live in a monorepo at skic-v1-playground in Gitea. Each application is a top-level directory with its own build system.

skic-v1-playground/
│
├── documentation/              # This Docusaurus site
│
├── stock-market-pro/           # Go application
│   ├── cmd/
│   │   └── server/
│   │       └── main.go         # Entrypoint
│   ├── internal/
│   │   ├── ingestor/           # Data ingestion
│   │   ├── analysis/           # Technical analysis engine
│   │   ├── signals/            # Signal generation
│   │   └── notifier/           # Discord delivery
│   ├── pkg/                    # Shared public packages
│   ├── Dockerfile
│   ├── Makefile
│   └── go.mod
│
├── shared/                     # Cross-app shared libraries (Go modules)
│   ├── discord/                # Discord client
│   ├── config/                 # Config loader
│   └── telemetry/              # Logging, metrics, tracing
│
├── infra/                      # Infrastructure-as-code
│   ├── docker-compose.yml      # Local dev stack
│   └── gitea-runners/          # CI runner config
│
└── Makefile                    # Root-level make targets (build all, test all)

Go Workspace (go.work)

The monorepo uses Go workspaces so all Go modules can reference each other without publishing:

# go.work
go 1.22

use (
    ./stock-market-pro
    ./shared/discord
    ./shared/config
    ./shared/telemetry
)

This means local changes to shared/ are immediately reflected across all Go apps without replace directives in individual go.mod files.

Tech Stack

Applications — Go

Go is the primary language for all backend services and autonomous applications.

Why Go:

• Statically typed, compiled, single binary deployment
• Excellent concurrency primitives (goroutines, channels) — ideal for market data streams
• Native cross-compilation
• Fast build times, clean toolchain
• Standard library covers most needs (HTTP, JSON, time, crypto)

Standard libraries:

Package	Purpose
net/http	HTTP server / client
encoding/json	JSON serialization
database/sql + modernc.org/sqlite	SQLite (dev)
github.com/lib/pq	PostgreSQL / TimescaleDB (prod)
github.com/rs/zerolog	Structured logging
github.com/spf13/viper	Config management
github.com/robfig/cron/v3	Scheduled jobs
golang.org/x/sync	Concurrency utilities

Data / Analysis — Python

Python is used for data science and ML-heavy workloads where the Go ecosystem is thin:

• pandas, numpy — data manipulation
• pandas-ta, ta-lib — technical indicators
• scikit-learn — pattern recognition / ML
• statsmodels — GARCH, time series

When Python is used, it runs as a sidecar service alongside the Go application, exposing a local HTTP/gRPC API.

Frontend / Docs — TypeScript + React

• Docusaurus v3 for documentation
• React + shadcn/ui + Tailwind for interactive components within docs

Code Conventions

Go

• gofmt — enforced in CI
• Error handling — always wrap with fmt.Errorf("context: %w", err), never ignore
• Packages — flat, purposeful. No circular dependencies. internal/ for app-private code
• Config — environment variables via Viper, validated at startup
• Logging — structured JSON via zerolog, no fmt.Println in production code
• Tests — table-driven tests in _test.go files, testify/assert for assertions

// Good — explicit error context
if err := db.Query(ctx, q); err != nil {
    return fmt.Errorf("ingestor: fetch candles: %w", err)
}

// Bad — swallowed error
db.Query(ctx, q)

Git

• Branch naming: feat/description, fix/description, docs/description
• Commit messages: conventional commits — feat:, fix:, docs:, chore:, refactor:
• PRs: all changes via PR, even from Jarvis — CI must pass before merge
• Main is always deployable

Makefile Targets (per app)

build:      ## Build binary
    go build -o bin/server ./cmd/server

test:       ## Run tests
    go test ./... -race -cover

lint:       ## Run linter
    golangci-lint run

docker:     ## Build Docker image
    docker build -t $(APP_NAME):$(VERSION) .

run:        ## Run locally with .env
    source .env && go run ./cmd/server

Adding a New Application

1. Create directory skic-v1-playground/<app-name>/
2. Initialize Go module: go mod init gitea.lego-cloud.eu/skic-v1-playground/<app-name>
3. Add to go.work: use ./<app-name>
4. Create .gitea/workflows/build.yml from the CI template
5. Create Dockerfile (multi-stage: golang:1.22-alpine → alpine:3.19)
6. Add documentation under documentation/docs/products/<app-name>/ following C4 structure
7. Add to homepage application table