ADR-004: Railway Deployment — Docker + Managed PostgreSQL

Status: Accepted
Date: 2026-04-17

Context

Need a zero-config production deployment for the GS experiment that supports Dockerfile builds, managed PostgreSQL, and health checks.

Decision

Railway with a Dockerfile builder and Railway-managed PostgreSQL plugin. DATABASE_URL injected via $ variable reference.

Key Configuration

• Prisma binary target: linux-musl-openssl-3.0.x — required for node:20-alpine; Alpine uses musl libc + OpenSSL 3
• Runner image: apk add --no-cache openssl in Dockerfile runner stage
• Start command: sh -c 'npx prisma migrate deploy && node dist/server.js' — migrations run before server starts
• Health check: GET /health → { status: "ok" } — Railway polls this before marking deploy healthy
• Rate limiting: disabled in non-production environments to allow harness runs without hitting limits

Consequences

• First deploy attempt failed due to missing OpenSSL on Alpine — resolved by adding binaryTargets and apk add openssl
• Rate limit must be tuned per environment: 500/min in production (configurable via env vars)
• Cold starts on Railway free tier add ~2-3s latency to first request after idle period