CazVid Infra — Only‑Main + Fargate Previews

Goals

Only‑main trunk: main is always releasable.
Build once, promote many: PR → preview → prod uses the same image SHA.
Parallel QA: per‑PR preview URLs (web & API), no staging trains.
Low‑ops: single ECS cluster, ephemeral Fargate services, auto‑cleanup.
Monorepo: unified CI, shared contracts.

Read next → Delivery (CI/CD & Runtime) · Operations (Net/Obs/Cost)

Monorepo Layout


cazvid/
  apps/
    web/        # Next.js (App Router)
    api/        # NestJS backend
  packages/
    contracts/  # shared TS types (gradual)
    config/     # lint, tsconfig, scripts
  .gitlab-ci.yml
  turbo.json
  package.json  # workspaces

Transition (no drift)

Import histories via git subtree add into apps/web and apps/api.
Optional one‑way sync jobs pull latest from old repos during cutover.
Flip PRs to monorepo as source of truth after a short proving window.

High‑Level Flow


Dev PR ──▶ CI builds image (web/api) ──▶ push to ECR
│
├─▶ Create ECS TaskDef + TG + Service (Fargate)
│       └─▶ ALB host rule: web-pr-###.qa.domain
│
└─▶ Post preview URL to MR
QA validates on preview ──▶ Merge to main ──▶ CI updates prod service to same image ──▶ Tag release
TTL job/merge/close ──▶ Destroy preview (rule + TG + service)

Key components

ALB: single public ALB + wildcard DNS *.qa.domain → host‑header rules → Target Groups.
ECS: one cluster; Fargate launch type for previews (and optionally prod).
Logs: CloudWatch log groups per app (/ecs/cazvid-web, /ecs/cazvid-api).

Environments

Production: ECS services web-prod, api-prod.
Previews (per PR): web-pr-<iid>, api-pr-<iid> + ALB host rules:
- https://web-pr-<iid>.qa.domain
- https://api-pr-<iid>.qa.domain
Staging (optional): fixed service from main with feature flags.

Day‑0 → Day‑2 Rollout

Day 0

Create monorepo & import histories.
Add web preview pipeline + wildcard DNS *.qa.domain → ALB.
Deploy a sample PR; verify URL.

Day 1

Add API preview pipeline; set FE API_BASE_URL to matched API preview.
Add TTL cleanup schedule.

Day 2

Flip team PRs to monorepo; old repos read‑only.
Adopt Conventional Commits & tag on main merges.
(Optional) Move shared types into packages/contracts.

Outcome: Monorepo + only‑main + Fargate previews ⇒ fastest path to “fix → preview URL → QA → ship.”