Router (Deprecated)

Deprecated

The @walkeros/transformer-router package has been removed. Conditional routing is now built directly into the next and before config properties using the same Route[] syntax.

Migration

Replace the router transformer with Route[] on the source's next property (or any step's next/before).

Before (transformer-router)

{
  "sources": {
    "express": { "package": "@walkeros/server-source-express", "next": "router" }
  },
  "transformers": {
    "router": {
      "package": "@walkeros/transformer-router",
      "config": {
        "settings": {
          "routes": [
            { "match": { "key": "path", "operator": "prefix", "value": "/gtag" }, "next": "gtag-parser" },
            { "match": "*", "next": "default-parser" }
          ]
        }
      }
    },
    "gtag-parser": { "package": "..." },
    "default-parser": { "package": "..." }
  }
}

After (native routing)

{
  "sources": {
    "express": {
      "package": "@walkeros/server-source-express",
      "next": [
        { "match": { "key": "ingest.path", "operator": "prefix", "value": "/gtag" }, "next": "gtag-parser" },
        { "match": "*", "next": "default-parser" }
      ]
    }
  },
  "transformers": {
    "gtag-parser": { "package": "..." },
    "default-parser": { "package": "..." }
  }
}

The next property now accepts three forms:

Form	Example	Description
string	"enricher"	Single transformer, walks transformer.next links
string[]	["a", "b", "c"]	Explicit chain, executed in order
Route[]	[{ match, next }]	Conditional routing based on ingest data

Route syntax

Each route has a match expression and a next target:

interface Route {
  match: MatchExpression | '*';  // Condition or wildcard
  next: string | string[] | Route[];  // Chain target (supports nesting)
}

Routes are evaluated in order. The first match wins. Use '*' as a catch-all wildcard at the end.

Match operators, logical combinators (and/or), and negation (not: true) work exactly as before. See the match expression reference for details.

Where routing works

Conditional Route[] routing works on:

• source.next: route events before the collector based on ingest data (path, method, headers)
• transformer.next: route after a transformer based on ingest data
• destination.before: route before a destination based on ingest data

Nested routes

Routes can nest to any depth:

{
  "next": [
    {
      "match": { "key": "ingest.path", "operator": "prefix", "value": "/api" },
      "next": [
        { "match": { "key": "ingest.method", "operator": "eq", "value": "POST" }, "next": "api-writer" },
        { "match": "*", "next": "api-reader" }
      ]
    },
    { "match": "*", "next": "default" }
  ]
}

Performance

Routes are compiled to closures at init time. Regular expressions are compiled once. Runtime evaluation uses short-circuit logic for and/or combinators.