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Stoma

Shadow Release

Use Case

Section titled “Use Case”

Mirror production traffic to a new upstream version without affecting user responses.

Recipe

Section titled “Recipe”
{
  path: "/v1/orders/*",
  methods: ["GET", "POST", "PUT"],
  pipeline: {
    policies: [
      trafficShadow({
        target: "https://orders-v2.internal.example.com",
        percentage: 10,
        methods: ["POST", "PUT"],
        timeout: 3000,
      }),
    ],
    upstream: {
      type: "url",
      target: "https://orders-v1.internal.example.com",
    },
  },
}

Why it works

Section titled “Why it works”
  • Primary responses still come from stable v1.
  • v2 receives realistic traffic for verification.
  • Shadow failures do not impact users.

Operational tip

Section titled “Operational tip”

Use the adapter waitUntil capability in Cloudflare (cloudflareAdapter({ executionCtx })) so shadow requests continue even after the primary response is returned.