schema_version: 1
diagram_type: sequence
meta:
  title: Cache Miss Request Sequence
  output: examples/sequence-cache-miss-request.html
  viewBox: [1080, 580]
  column_fit: spread
  animation: trace
  quality_profile: showcase
participants:
  - id: user
    type: external
    label: User
    sublabel: browser session
  - id: web
    type: frontend
    label: Web App
    sublabel: React UI
  - id: api
    type: backend
    label: API
    sublabel: request handler
  - id: auth
    type: security
    label: Auth
    sublabel: JWT verify
  - id: redis
    type: database
    label: Redis
    sublabel: cache
  - id: db
    type: database
    label: Postgres
    sublabel: source of truth
  - id: trace
    type: messagebus
    label: Trace
    sublabel: async event
segments:
  - from: 150
    to: 250
    label: Request
  - from: 260
    to: 370
    label: Fallback
  - from: 380
    to: 480
    label: Response + trace
messages:
  - id: open-page
    from: user
    to: web
    y: 160
    label: open page
    variant: default
  - id: dashboard-request
    from: web
    to: api
    y: 185
    label: GET /dashboard
    variant: emphasis
  - id: verify-jwt
    from: api
    to: auth
    y: 210
    label: verify JWT
    variant: security
  - id: auth-claims
    from: auth
    to: api
    y: 238
    label: claims ok
    variant: return
  - id: cache-read
    from: api
    to: redis
    y: 270
    label: read cache
    variant: default
  - id: cache-miss
    from: redis
    to: api
    y: 298
    label: miss
    variant: return
  - id: profile-query
    from: api
    to: db
    y: 330
    label: query profile + metrics
    variant: emphasis
  - id: profile-rows
    from: db
    to: api
    y: 358
    label: rows
    variant: return
  - id: cache-write
    from: api
    to: redis
    y: 390
    label: set cache
    variant: dashed
  - id: trace-emit
    from: api
    to: trace
    y: 418
    label: emit trace
    variant: dashed
  - id: dashboard-response
    from: api
    to: web
    y: 443
    label: 200 JSON
    variant: return
  - id: page-render
    from: web
    to: user
    y: 468
    label: render
    variant: return
activations:
  - participant: web
    from: 180
    to: 474
    type: frontend
  - participant: api
    from: 185
    to: 450
    type: backend
  - participant: auth
    from: 205
    to: 244
    type: security
  - participant: redis
    from: 265
    to: 304
    type: database
  - participant: db
    from: 325
    to: 364
    type: database
  - participant: trace
    from: 413
    to: 449
    type: messagebus
cards:
  - dot: emerald
    title: Happy Path
    items:
      - The main request is Web App -> API -> data source -> response
      - Return messages are quieter than forward calls
      - Activation bars make ownership duration visible
  - dot: rose
    title: Policy + Fallback
    items:
      - JWT verification is colored as a security interaction
      - Cache miss is visible without overpowering the main path
      - Database access only appears after cache fallback
  - dot: orange
    title: Async Trace
    items:
      - Trace emission is dashed and secondary
      - It does not block the response path
      - The diagram separates user-facing latency from observability