version: 1
id: gateway-canary-split
title: Plan Gateway Canary Traffic Splits
summary: Design an HTTPRoute weight split between stable and canary Services, plus a rollback checklist.
difficulty: intermediate
estimatedMinutes: 25
prerequisites: [gateway-api-http-route, observability-metrics-alerts]
image: alpine:3.21
shell: /bin/sh
setup:
  - "mkdir -p /workspace/gateway /workspace/docs"
  - "printf 'Ticket: canary payments-api at 10%% weight.\\nNeed weighted backendRefs and a rollback checklist.\\n' > /workspace/gateway/TICKET.md"
tasks:
  - id: weighted-route
    title: Author weighted HTTPRoute
    description: 'Create /workspace/gateway/canary-route.yaml with kind: HTTPRoute, metadata.name payments-api-canary, hostnames including api.payments.example, and backendRefs for payments-api (weight 90) and payments-api-canary (weight 10). Include both Service names and both weights literally.'
    hints:
      - 'Tip code WEIGHT_SPLIT: backendRefs weights should sum to 100 for a clean canary.'
      - 'Tip code CANARY_NAME: keep canary Service distinct (payments-api-canary).'
      - 'Include weight: 90 and weight: 10.'
    checks:
      - type: file
        name: Canary route present
        path: /workspace/gateway/canary-route.yaml
        value: "kind: HTTPRoute"
      - type: file
        name: Route named
        path: /workspace/gateway/canary-route.yaml
        value: payments-api-canary
      - type: file
        name: Stable service present
        path: /workspace/gateway/canary-route.yaml
        value: payments-api
      - type: file
        name: Canary service present
        path: /workspace/gateway/canary-route.yaml
        value: payments-api-canary
      - type: file
        name: Host configured
        path: /workspace/gateway/canary-route.yaml
        value: api.payments.example
      - type: command
        name: Stable weight 90
        command: "grep -Eq 'weight:[[:space:]]*90' /workspace/gateway/canary-route.yaml"
      - type: command
        name: Canary weight 10
        command: "grep -Eq 'weight:[[:space:]]*10' /workspace/gateway/canary-route.yaml"
  - id: rollback-checklist
    title: Write canary rollback checklist
    description: 'Write /workspace/docs/CANARY.md with headings Metrics, Promote, and Rollback. Metrics must mention error rate or latency. Promote must mention 100% or weight 100. Rollback must mention weight 0 or remove canary. Write /workspace/gateway/STATUS.txt containing CANARY_OK.'
    hints:
      - 'Tip code CANARY_METRICS: watch error rate/latency before promoting weights.'
      - 'Tip code CANARY_ROLLBACK: rollback is weight 0 (or detach) on the canary backendRef.'
      - 'STATUS.txt should include CANARY_OK.'
    checks:
      - type: file
        name: Metrics section present
        path: /workspace/docs/CANARY.md
        value: Metrics
      - type: file
        name: Promote section present
        path: /workspace/docs/CANARY.md
        value: Promote
      - type: file
        name: Rollback section present
        path: /workspace/docs/CANARY.md
        value: Rollback
      - type: command
        name: Metrics mention SLIs
        command: "grep -A3 '^#* *Metrics' /workspace/docs/CANARY.md | grep -Eqi 'error rate|latency'"
      - type: command
        name: Promote mentions full weight
        command: "grep -A3 '^#* *Promote' /workspace/docs/CANARY.md | grep -Eqi '100%|weight 100|100'"
      - type: command
        name: Rollback mentions zeroing canary
        command: "grep -A3 '^#* *Rollback' /workspace/docs/CANARY.md | grep -Eqi 'weight 0|remove canary|detach'"
      - type: file
        name: Canary status ok
        path: /workspace/gateway/STATUS.txt
        value: CANARY_OK
limits: {cpus: "0.5", memory: 128m, pids: 64, timeout: 1800, network: false}